SGM41526_技术文档

SGM41526/SGM41527

1.6MHz Synchronous Li-Ion and Li-Polymer

Stand-Alone Battery Chargers

with Automatic Power Path Selector

● High Accuracy

FEATURES

 ±0.4% Charge Voltage Regulation

 ±5% Charge Current Regulation

 ±4% Input Current Regulation

● Safety

● 4A Synchronous 1.6MHz PWM Charger

 Cycle-by-Cycle Current Limit

 Integrated 24V Switching MOSFETs

 Integrated Bootstrap Diode

 Digital Soft-Start

 Thermal Regulation (Current Limit for T_J= +120℃)

 Thermal Shutdown

● Up to 95.2% Charge Efficiency

 Battery Thermistor Sense Hot/Cold Charge Suspend

● 30V Absolute Maximum Input Voltage Rating with

Adjustable Over-Voltage Threshold

 Input Under-Voltage Lockout (UVLO)

 Input Over-Voltage (ACOV) Protection

● 4.5V to 22V Input Operating Voltage Range

● Automatic Power Path Selector (Battery/Adapter)

● Dynamic Power Management (DPM)

● Battery Charge Voltage

APPLICATIONS

Tablet PCs

 SGM41526: Select 2-, 3-, or 4-Cell with 4.2V/Cell

 SGM41527: Adjustable Charge Voltage

● 18μA Battery Current (No Adapter)

Portable Terminals and Printers

Portable Medical Equipment

Battery Backup Systems

● 1.3mA Input Current (Charge Disabled)

TYPICAL APPLICATION

R_AC

10mΩ

Q1

Q2

I_IN

V_IN

I_OUT

12V

Adapter

Input

V_SYS

System

R_IN

2Ω

C₁₁

0.1μF

C₄

10μF

C₁₂

0.1μF

ACN PVCC

nBATDRV

R₁₂

4.02kΩ

ACP

CMSRC

C_IN

2.2μF

R₁₄1kΩ

Q3

R₁₁

4.02kΩ

L

R_SR

10mΩ

ACDRV

3.3μH

V_BAT

C₁₀

R₆1MΩ

SW

OVPSET

R₇

100kΩ

R₁10Ω

C₉

C₅

0.047μF

D1

C₈

0.1μF

SGM41526

D4

10μF 10μF

D2

V_BAT

BTST

AVCC

C₁

1μF

I_BAT

REGN

C₆

V_REF

1μF

VREF

ISET

R₄

R₂

232kΩ

PGND

100kΩ

C₇

0.1μF

R_T

R₃

103AT

SRP

SRN

32.4kΩ

V_REF

R₈

5.23kΩ

ACSET

CELL

C₂

1μF

R₅

22.1kΩ

Floating

TS

R₁₀

1.5kΩ

C₃

0.1μF

R₉

30.1kΩ

Thermal

Pad

TTC

STAT

(AGND)

D3

Figure 1. SGM41526 Typical Application Circuit (with a 2-Cell Battery)

SG Micro Corp

MARCH 2023 – REV. A. 2

www.sg-micro.com

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

GENERAL DESCRIPTION

The SGM41526 and SGM41527 are stand-alone Li-Ion and

Li-polymer battery chargers. The PWM switches are integrated

inside and they can automatically select the power path. They

also include gate drivers for external power path selector

MOSFETs. The synchronous PWM controller runs at a fixed

frequency (1.6MHz) and is capable of providing accurate

regulation of charge voltage, charge current and input current.

They are capable of providing continuous battery pack

temperature monitoring in which the charge is only allowed

when the temperature is within the desired range. The

SGM41526 can charge 2-, 3- or 4-cell (selected by CELL pin);

while the SGM41527 has an adjustable charge voltage for up

to 4 cells. In the SGM41527, the FB pin is used for charge

voltage regulation (feedback) using an internal 2.1V reference

and comparator.

The SGM41526 and SGM41527 use dynamic power

management (DPM) to prevent overload of the input source

(AC adaptor). With DPM, the output charge current is reduced

if the input power limit is reached. The input current is sensed

and controlled by a precision current-sense amplifier to limit the

input power.

Gate driver outputs are provided for power path selection that

can be achieved by three external switches. Two N-type

back-to-back MOSFETs (Q1, Q2) are used as input pair

(adapter power in and reverse blocking control) along with a

P-type (Q3) that is used to control the battery connection to the

system bus. The system is powered from adapter by Q1 and

Q2 on if a qualified adapter is present. Otherwise, the system is

connected to the battery by Q3. And with power path control,

the battery cannot feed back to the input.

Typically, a full battery charging cycle has three consequent

phases: pre-conditioning, constant current and constant

voltage. The charge current is small during the pre-conditioning

phase in which battery is heavily depleted. When the battery

voltage exceeds a threshold voltage, the charge current

increases to its maximum (fast charge current) until the battery

voltage reaches its regulation level. Then the voltage is

regulated and charge current drops. The starting phase is

determined by the initial battery voltage. In constant voltage

condition, the charge current drops automatically. When it

decreases below 10% of the fast charge value, charging is

terminated. A programmable safety charge timer is provided to

prevent prolonged charging if it is not naturally terminated for

any reason. When the battery voltage falls below recharge

threshold, charge cycle is automatically started (or restarted).

The SGM41526 and SGM41527 can charge the battery from a

DC source with a voltage up to 22V. This range covers

common adapter voltages and the car battery voltage. The

qualified adapter range is adjustable by OVPSET pin. If the

input voltage is out of the range, Q1 and Q2 will not be turned

on.

For 1-cell applications (only applicable to SGM41527), when

the battery is not removable, the design can be simplified by

direct connection of the battery to the system. Therefore, when

the input source is overloaded, the battery can help power the

system automatically.

The SGM41526 and SGM41527 are available in a Green

TQFN-5.5×3.5-24L package. It can operate over an ambient

temperature range of -40℃ to +85℃.

If the input voltage falls below the battery voltage, the device

enters sleep mode. In sleep mode, the quiescent current is

very low.

SG Micro Corp

www.sg-micro.com

MARCH 2023

2

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

PACKAGE/ORDERING INFORMATION

SPECIFIED

TEMPERATURE

PACKAGE

DESCRIPTION

ORDERING

NUMBER

PACKAGE

MARKING

PACKING

OPTION

MODEL

RANGE

SGM41526

YTQQ

XXXXX

SGM41526 TQFN-5.5×3.5-24L

SGM41527 TQFN-5.5×3.5-24L

-40℃ to +85℃

SGM41526YTQQ24G/TR

Tape and Reel, 3000

SGM41527

YTQQ

XXXXX

SGM41527YTQQ24G/TR

MARKING INFORMATION

NOTE: XXXXX = Date Code, Trace Code and Vendor Code.

X X X X X

Vendor Code

Trace Code

Date Code - Year

Green (RoHS & HSF): SG Micro Corp defines "Green" to mean Pb-Free (RoHS compatible) and free of halogen substances. If

you have additional comments or questions, please contact your SGMICRO representative directly.

OVERSTRESS CAUTION

ABSOLUTE MAXIMUM RATINGS

Stresses beyond those listed in Absolute Maximum Ratings

may cause permanent damage to the device. Exposure to

absolute maximum rating conditions for extended periods

may affect reliability. Functional operation of the device at any

conditions beyond those indicated in the Recommended

Operating Conditions section is not implied.

AGND Referenced Voltages

PVCC............................................................... -0.3V to 24V

AVCC, ACP, ACN, ACDRV, CMSRC, STAT...... -0.3V to 30V

BTST................................................................ -0.3V to 30V

nBATDRV, SRP, SRN ...................................... -0.3V to 24V

SW ...................................................................... -2V to 24V

FB (SGM41527)............................................... -0.3V to 24V

CELL (SGM41526), OVPSET, REGN, TS, TTC

ESD SENSITIVITY CAUTION

........................................................................... -0.3V to 7V

VREF, ISET, ACSET ....................................... -0.3V to 3.6V

PGND ............................................................. -0.3V to 0.3V

Differential Voltages

This integrated circuit can be damaged if ESD protections are

not considered carefully. SGMICRO recommends that all

integrated circuits be handled with appropriate precautions.

Failureto observe proper handlingand installation procedures

can cause damage. ESD damage can range from subtle

performance degradation tocomplete device failure. Precision

integrated circuits may be more susceptible to damage

because even small parametric changes could cause the

device not to meet the published specifications.

SRP-SRN, ACP-ACN........................................ -0.5V to 0.5V

Package Thermal Resistance

TQFN-5.5×3.5-24L, θ_JA........................................... 37.4℃/W

Junction Temperature.................................................+150℃

Storage Temperature Range.......................-65℃ to +150℃

Lead Temperature (Soldering, 10s)............................+260℃

ESD Susceptibility

DISCLAIMER

HBM.............................................................................2000V

CDM ............................................................................1000V

SG Micro Corp reserves the right to make any change in

circuit design, or specifications without prior notice.

RECOMMENDED OPERATING CONDITIONS

Input Voltage Range, V_IN......................................4.5V to 22V

Output Voltage, V_BAT.............................................18V (MAX)

Output Current Range (R_SR= 10mΩ), I_OUT.............0.6A to 4A

Maximum Differential Voltage

SRP-SRN, ACP-ACN................................ -200mV to 200mV

Operating Temperature Range ......................-40℃ to +85℃

SG Micro Corp

www.sg-micro.com

MARCH 2023

3

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

PIN CONFIGURATION

(TOP VIEW)

SW

24

1

PGND

BTST

REGN

PVCC

AVCC

ACN

2

3

4

5

6

23

22

21

20

19 nBATDRV

18 OVPSET

ACP

AGND

CMSRC

ACDRV

STAT

7

8

9

17

16

15

ACSET

SRP

SRN

TS 10

11

EP

14 CELL/FB

TTC

12

13

VREF

ISET

TQFN-5.5×3.5-24L

PIN DESCRIPTION

NAME

TYPE

FUNCTION

1, 24

SW

P

Switching Node. Connect SW pin to the output inductor and also to a bootstrap capacitor from BTST pin.

Charger Input Voltage. Decouple with at least 10μF ceramic capacitor from PVCC pin to PGND as close

to IC as possible.

2, 3

4

PVCC

AVCC

P

IC Supply Power. Place an RC filter (10Ω-1μF) with ceramic capacitor from input power to AVCC pin to

AGND and place capacitor close to the IC. For 5V input, a minimum 5Ω resistor is recommended. The

device under-voltage lockout (UVLO) is sensed on AVCC pin (typically 3.3V rising with 0.21V hysteresis).

Input Current Sense Resistor Negative Input. Connect a 100nF ceramic capacitor from ACN to ACP for

differential-mode filtering. Connect a 100nF ceramic capacitor from ACN to AGND for common-mode

filtering.

5

6

7

ACN

ACP

I

Input Current Sense Resistor Positive Input. Connect a 100nF ceramic capacitor from ACN to ACP for

differential-mode filtering. Connect an optional 100nF ceramic capacitor from ACP to AGND for

common-mode filtering.

I/P

O

Common Source of the ACFET and RBFET. Connect with a 4.02kΩ resistor to the common source of the

input MOSFET ACFET (Q1) and RBFET (Q2) to control the turn-on speed and limit inrush current. An

external minimum 500kΩ resistor between ACDRV pin and CMSRC pin is essential.

CMSRC

Gate Driver Output for Input Switches. A 4.02kΩ resistor is placed to the common gate of the external

N-channel ACFET and RBFET power MOSFETs. Connect both FETs as common source. It has

break-before-make logic with respect to the nBATDRV and acts asymmetrical, allowing quick turn-off and

slow turn-on.

8

9

ACDRV

STAT

O

Open-Drain Charge Status Output Pin with 10kΩ External Pull-Up to the Power Rail. It can be connected

to LED to show the charging status or it can directly communicate with the host. The STAT pin acts as

follows:

During charge: low (LED ON).

Charge completed, charger in sleep mode or charge disabled: high (LED OFF).

Charge suspend (in response to a fault): 1Hz, including battery detection, charge suspend, input

over-voltage, battery over-voltage, and timer fault. (LED BLINKS).

SG Micro Corp

www.sg-micro.com

MARCH 2023

4

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

PIN DESCRIPTION (continued)

NAME

TYPE

FUNCTION

Temperature Sense Voltage Input. Connect to a negative temperature coefficient (NTC) thermistor that

can sense the battery temperature. The actual hot and cold temperature can be set by a resistor divider

from VREF to TS to AGND. It is recommended to use a 103AT type thermistor for battery pack

temperature sensing.

10

TS

I

Safety Timer (Fast Charge) and Termination Control. Pre-charge timer is fixed inside the device (30min

typically). Fast charge safety timer is determined by the capacitor from this pin to AGND (5.6min/nF).

Safety timer is disabled by pulling this pin low or high, but charge termination is disabled only when it is

pulled low.

11

12

TTC

I

3.3V Voltage Reference Output Internally Powered from AVCC Pin. Connect a 1μF ceramic capacitor to

AGND as close to IC as possible. It is usually connected to the resistor divider of ISET, ACSET and TS

pins. It can also be connected to STAT and CELL pins as pull-up rail.

VREF

P

Program Pin for Charge Current Settings. The voltage on this pin and the charge shunt resistor R_SR

determine the fast charge current. V_ISETvoltage can be set by a resistor divider (VREF-ISET-AGND).

V

ISET

I_CHG

=

13

14

ISET

I

20×R_SR

The pre-charge and termination currents are equal and determined by I_CHGas a ratio of 10%.

The charger disables when ISET voltage is pulled below 30mV and enables if it exceeds 120mV.

CELL

(SGM41526)

Cell Selection Pin for SGM41526. Set it low for 4-cell battery, floating for 2-cell, and set it high for 3-cell

battery. Cell voltage regulation is fixed at 4.2V per cell.

Feedback Pin for Regulating the Charge Voltage in SGM41527 in the Constant-Voltage Mode. A resistor

divider from battery terminal (V_BAT) to FB (V_FB) to AGND sets the charge voltage. And the internal

voltage reference is 2.1V.

FB

(SGM41527)

Charge Current Sense Resistor, Negative Input. A shunt resistor is connected between SRN pin and

SRP pin to sense charge current. Connect a 100nF ceramic capacitor between SRN pin and SRP pin

for differential-mode filtering. Connect an optional 100nF capacitor between SRN and AGND for

common-mode filtering.

15

16

SRN

SRP

I

Charge Current Sense Resistor, Positive Input. Connect a 100nF ceramic capacitor between SRN pin

and SRP pin for differential-mode filtering. Connect another 100nF ceramic capacitor between SRP pin

and AGND for common-mode filtering.

I/P

Program Pin to Set Input Current Limit for Dynamic Power Management. A voltage divider from VREF to

ACSET to AGND can be used to set this parameter along with the input shunt resistor R_AC

:

17

18

ACSET

I

V_ACSET

I_DPM

=

20×R_AC

Program Pin for Input Over-Voltage Detection. The input voltage can be sensed by a resistor voltage

divider from input to OVPSET to AGND so that the ACOV and ACUV can be realized by setting proper

resistor. An input over-voltage (ACOV) is detected if OVPSET voltage exceeds the internal 1.6V

reference. A voltage below 0.494V indicates an input under-voltage (ACUV). If either of the two cases

happens, both of the ACFET and RBFET will be turned off. If it is in charging process, the charge will

terminate. Then the LED that is connected to STAT pin will blink at 1Hz to indicate a fault.

OVPSET

Gate Driver Output for External P-Type Power MOSFET (Battery Discharge Path). Use a 1kΩ resistor to

connect this pin to the gate of the BATFET (Q3) to control the turn-on speed. The source of the BATFET

connects to the system and the drain connects to the battery positive terminal. In order to decrease

inrush current, the internal gate driver is designed with quick turn-off and slow turn-on functions.

This gate driver has break-before-make logic with respect to the ACDRV gate driver (input switch).

19

nBATDRV

O

5V Internal Supply for the PWM Low-side Switch Driver. Decouple with a 1μF ceramic capacitor from

REGN pin to PGND pin close to the IC. Anode of integrated bootstrap diode is connected to this pin.

20

21

REGN

BTST

PGND

P

High-side Power MOSFET Driver Power Supply. Connect a 47nF bootstrap capacitor from SW to BTST.

Device Power Ground. On the PCB layout, connect this pin directly to ground points of the input and

output capacitors of the charger. PGND connects to AGND only through in one point on thermal pad

under the IC.

22, 23

Exposed Pad Beneath the IC. Always solder thermal pad to the board. Use vias to transfer heat to the

back side and other layers of PCB. Thermal pad acts as AGND and only connects to PGND at one

single point.

EP

AGND

P

NOTE:

1. I = Input, O = Output, P = Power.

SG Micro Corp

www.sg-micro.com

MARCH 2023

5

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

ELECTRICAL CHARACTERISTICS

(T_J= -40℃ to +85℃, 4.5V ≤ V_PVCC, V_AVCC≤ 22V (referred to AGND), typical values at T_J= +25℃, unless otherwise noted.)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Operating Conditions

AVCC Input Voltage Operating Range

during Charging

V_{AVCC_OP}

4.5

22

V

Quiescent Currents

V

_AVCC> V_UVLO, V_SRN> V_AVCC(Sleep),

7.4

18

15

30

T_J= 0℃ to +85℃

Battery Discharge Current

(Sum of Currents into AVCC, PVCC,

ACP, ACN)

BTST, SW, SRP, SRN, V_AVCC> V_UVLO, V_AVCC> V_SRN

V_ISET< 30mV, V_BAT= 12.6V, charge disabled

,

I_BAT

µA

BTST, SW, SRP, SRN, V_AVCC> V_UVLO, V_AVCC> V_SRN

V_ISET> 120mV, V_BAT= 12.6V, charge done

18

30

V

_AVCC> V_UVLO, V_AVCC> V_SRN, V_ISET< 30mV,

_BAT= 12.6V, charge disabled

1.3

1.4

15 ⁽¹⁾

2.0

Adapter Supply Current

(Sum of Currents into AVCC, ACP, ACN)

V_AVCC> V_UVLO, V_AVCC> V_SRN, V_ISET> 120mV,

charge enabled, no switching

I_AC

mA

V_AVCC> V_UVLO, V_AVCC> V_SRN, V_ISET> 120mV,

charge enabled, switching

Charge Voltage Regulation

CELL floating, 2-cell, measured on SRN

CELL to VREF, 3-cell, measured on SRN

CELL to AGND, 4-cell, measured on SRN

Measure on FB

8.4

12.6

16.8

2.1

SRN Regulation Voltage (SGM41526)

V_{BAT_REG}

V

SRN Regulation Voltage (SGM41527)

Charge Voltage Regulation Initial Accuracy

Current Regulation - Fast Charge

ISET Voltage Range

V_{FB_REG}

V

-0.4

0.4

0.8

%

V_ISET

K_ISET

R_SENSE= 10mΩ

0.12

V

Charge Current Set Factor (Amps of

Charge Current per Volt on ISET Pin)

5

A/V

V

_SRP-SRN= 40mV

39.0

19.1

3.8

41.0

20.7

5.4

43.1

22.4

7.1

Charge Current Regulation Initial Accuracy

(with Schottky Diode on SW)

V_SRP-SRN= 20mV

V_SRP-SRN= 5mV

V_ISETfalling

mV

Charge Disable Threshold

Charge Enable Threshold

Leakage Current into ISET

Input Current Regulation

V_{ISET_CD}

V_{ISET_CE}

I_ISET

30

50

mV

nA

V_ISETrising

100

120

100

V_ISET= 2V

Input DPM Current Set Factor (Amps of

Input Current per Voltage on ACSET)

K_DPM

R_SENSE= 10mΩ

5

A/V

V

_ACP-ACN= 80mV

78.3

37.3

17.6

4.2

81.6

41.0

20.7

5.5

84.8

44.7

23.8

6.9

V_ACP-ACN= 40mV

V_ACP-ACN= 20mV

V_ACP-ACN= 5mV

V_ACP-ACN= 2.5mV

V_ACSET= 2V

Input DPM Current Regulation Initial

Accuracy (with Schottky Diode on SW)

mV

nA

1.5

3.0

4.5

Leakage Current into ACSET Pin

I_ACSET

100

SG Micro Corp

www.sg-micro.com

MARCH 2023

6

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

ELECTRICAL CHARACTERISTICS (continued)

(T_J= -40℃ to +85℃, 4.5V ≤ V_PVCC, V_AVCC≤ 22V (referred to AGND), typical values at T_J= +25℃, unless otherwise noted.)

PARAMETER

Current Regulation - Pre-Charge

Pre-Charge Current Set Factor

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

K_IPRECHG

Percentage of fast charge current

V_SRP-SRN= 4mV

10 ⁽²⁾

4.6

%

3.4

1.3

5.7

3.8

Pre-Charge Current Regulation Initial Accuracy

mV

V_SRP-SRN= 2mV

2.5

Charge Termination

Termination Current Set Factor

K_TERM

Percentage of fast charge current

V_SRP-SRN= 4mV

10 ⁽²⁾

3.9

%

2.9

0.9

4.8

2.7

Termination Current Regulation Initial Accuracy

mV

V_SRP-SRN= 2mV

1.8

Deglitch Time for Termination (Both Edges)

Termination Qualification Time

t_{TERM_DEG}

t_QUAL

100

250

ms

V_SRN> V_RECHand I_CHG< I_TERM

Discharge current once termination is

detected

Termination Qualification Current

I_QUAL

2

mA

Input Under-Voltage Lockout Comparator (UVLO)

AC Under-Voltage Rising Threshold

AC Under-Voltage Hysteresis, Falling

V_UVLO

V_{UVLO_HYS}

Measure on AVCC

2.9

3.3

3.8

V

210

mV

Sleep Comparator (Reverse Discharging Protection)

Sleep Mode Threshold

V_SLEEP

V_AVCC- V_SRNfalling

V_AVCC- V_SRNrising

90

210

1

280

mV

ms

Sleep Mode Hysteresis

V_{SLEEP_HYS}

Sleep Deglitch to Disable Charge

Sleep Deglitch to Turn Off Input FETs

t_{SLEEP_FALL_CD}V_AVCC- V_SRNfalling

t_{SLEEP_FALL_FETOFF}V_AVCC- V_SRNfalling

5

Deglitch to Enter Sleep Mode, Disable VREF

and Enter Low Quiescent Mode

Deglitch to Exit SLEEP Mode, and Enable

VREF

t_{SLEEP_FALL}

V_AVCC- V_SRNfalling

100

30

ms

t_{SLEEP_PWRUP}V_AVCC- V_SRNrising

ACN-SRN Comparator

Threshold to Turn On BATFET

Hysteresis to Turn Off BATFET

Deglitch to Turn On BATFET

Deglitch to Turn Off BATFET

Battery LOWV Comparator

V_ACN-SRN

V_ACN-SRNfalling

180

110

2

400

mV

ms

µs

V_{ACN-SRN_HYS}V_ACN-SRNrising

t_{BATFETOFF_DEG}V_ACN-SRNfalling

t_{BATFETON_DEG}V_ACN-SRNrising

50

CELL floating, 2-cell

CELL to VREF, 3-cell

CELL to AGND, 4-cell

5.7

8.4

5.8

8.7

6.1

9.1

Measure on SRN

(SGM41526)

Pre-Charge to Fast Charge Transition

Fast Charge to Pre-Charge Hysteresis

V_LOWV

V

11.1

1.42

11.7

1.46

400

600

800

100

25

12.2

1.50

Measure on FB (SGM41527)

CELL floating, 2-cell

CELL to VREF, 3-cell

CELL to AGND, 4-cell

Measure on SRN

(SGM41526)

V_{LOWV_HYS}

mV

Measure on FB (SGM41527)

Delay to start fast charge current

Delay to start pre-charge current

V_LOWVRising Deglitch

V_LOWVFalling Deglitch

t_PRE2FAS

ms

t_FAST2PRE

25

SG Micro Corp

www.sg-micro.com

MARCH 2023

7

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

ELECTRICAL CHARACTERISTICS (continued)

(T_J= -40℃ to +85℃, 4.5V ≤ V_PVCC, V_AVCC≤ 22V (referred to AGND), typical values at T_J= +25℃, unless otherwise noted.)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Recharge Comparator

CELL floating, 2-cell

110

190

280

50

200

300

400

70

290

430

540

90

Recharge Threshold, below Regulation

Voltage Limit,

V_{BAT_REG}- V_SRN(SGM41526),

or V_{FB_REG}- V_FB(SGM41527)

Measure on SRN

(SGM41526)

CELL to VREF, 3-cell

CELL to AGND, 4-cell

V_RECHG

mV

Measure on FB (SGM41527)

V_RECHGRising Deglitch

t_{RECH_RISE_DEG}V_FBdecreasing below V_RECHG

t_{RECH_FALL_DEG}V_FBincreasing above V_RECHG

10

ms

V_RECHGFalling Deglitch

10

Battery Over-Voltage Comparator

As percentage of V_{BAT_REG}(SGM41526)

or V_{FB_REG}(SGM41527)

Over-Voltage Rising Threshold

V_{OV_RISE}

V_{OV_FALL}

104

102

%

As percentage of V_SRN(SGM41526)

or V_{FB_REG}(SGM41527)

Over-Voltage Falling Threshold

Input Over-Voltage Comparator (ACOV)

AC Over-Voltage Rising Threshold to

Turn Off ACFET

V_ACOV

OVPSET rising

OVPSET falling

1.53

1.6

40

1

1.69

V

AC Over-Voltage Falling Hysteresis

V_{ACOV_HYS}

mV

µs

AC Over-Voltage Rising Deglitch to

Turn Off ACFET and Disable Charge

AC Over-Voltage Falling Deglitch to

Turn On ACFET

t_{ACOV_RISE_DEG}OVPSET rising

t_{ACOV_FALL_DEG}OVPSET falling

30

ms

Input Under-Voltage Comparator (ACUV)

AC Under-Voltage Falling Threshold to

Turn Off ACFET

V_ACUV

OVPSET falling

OVPSET rising

0.44

0.494

80

0.55

V

AC Under-Voltage Rising Hysteresis

V_{ACUV_HYS}

mV

µs

AC Under-Voltage Falling Deglitch to

Turn Off ACFET and Disable Charge

AC Under-Voltage Rising Deglitch to

Turn On ACFET

t_{ACOV_FALL_DEG}OVPSET falling

t_{ACOV_RISE_DEG}OVPSET rising

1

30

ms

Thermal Regulation

Junction Temperature Regulation Accuracy

Thermal Shutdown Comparator

Thermal Shutdown Rising Temperature

Thermal Shutdown Hysteresis

Thermal Shutdown Rising Deglitch

Thermal Shutdown Falling Deglitch

Thermistor Comparator

T_{A_REG}

V_ISET> 120mV, charging

120

℃

T_SHUT

Temperature rising

Temperature falling

150

20

℃

T_{SHUT_HYS}

T_{SHUT_RISE_DEG}Temperature rising

T_{SHUT_FALL_DEG}Temperature falling

100

10

µs

ms

Cold Temperature Threshold, TS Pin

Voltage Rising Threshold

Charger suspends charge,

as percentage of V_VREF

V_LTF

72.1

73.6

75.2

%

Cold Temperature Hysteresis, TS Pin

Voltage Falling

Hot Temperature TS Pin Voltage Rising

Threshold

Cut-Off Temperature TS Pin Voltage

Falling Threshold

Deglitch Time for Temperature out of

Range Detection

V_{LTF_HYS}

V_HTF

As percentage of V_VREF

0.68

47.3

44.6

20

1.45

48.8

45.7

%

As percentage of V_VREF

45.8

43.2

V_TCO

As percentage of V_VREF

%

t_{TS_CHG_SUS}

V_TS> V_LTF, or V_TS< V_TCO, or V_TS< V_HTF

ms

Deglitch Time for Temperature in Valid

Range Detection

V_TS< V_LTF- V_{LTF_HYS}or V_TS> V_TCO

or V_TS> V_HTF

,

t_{TS_CHG_RESUME}

400

ms

SG Micro Corp

www.sg-micro.com

MARCH 2023

8

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

ELECTRICAL CHARACTERISTICS (continued)

(T_J= -40℃ to +85℃, 4.5V ≤ V_PVCC, V_AVCC≤ 22V (referred to AGND), typical values at T_J= +25℃, unless otherwise noted.)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX UNITS

Charge Over-Current Comparator (Cycle-by-Cycle)

Charge Over-Current Rising Threshold,

V_SRP> 2.2V

V_{OCP_CHRG}

V_{OCP_MIN}

V_{OCP_MAX}

Current as percentage of fast charge current

180

%

Charge Over-Current Limit Min, V_SRP< 2.2V

Measure V_SRP-SRN

46

77

mV

Charge Over-Current Limit Max, V_SRP> 2.2V

HSFET Over-Current Comparator (Cycle-by-Cycle)

Current Limit on HSFET

I_{OCP_HSFET}

Measure on HSFET

Measure on V_SRP-SRN

Measure on SRN

10

5

A

Charge Under-Current Comparator (Cycle-by-Cycle)

Charge Under-Current Falling Threshold

Battery Short Comparator

Battery Short Falling Threshold

Battery Short Rising Hysteresis

Deglitch on Both Edges

Charge Current during BAT_SHORT

VREF Regulator

V_UCP

1

12

mV

V_BATSHT

2

200

1

V

mV

µs

%

V_{BATSHT_HYS}Measure on SRN

t_{BATSHT_DEG}

V_BATSHT

Percentage of fast charge current

10 ⁽²⁾

VREF Regulator Voltage

VREF Current Limit

V_{VREF_REG}

I_{VREF_LIM}

V_AVCC> V_UVLO, no load

3.24

20

3.3

5.0

3.36

80

V

V_VREF= 0V, V_AVCC> V_UVLO

mA

REGN Regulator

REGN Regulator Voltage

REGN Current Limit

V_{REGN_REG}

I_{REGN_LIM}

V_AVCC> 10V, V_ISET> 120mV

4.8

20

5.2

V

V_REGN= 0V, V_AVCC> 10V, V_ISET> 120mV

100

mA

TTC Input

Pre-Charge Safety Timer

Fast Charge Timer Range

Fast Charge Timer Accuracy

Timer Multiplier

t_PRECHRG

t_FASTCHRG

Pre-charge time before fault occurs

T_CHG= C_TTC× K_TTC

1800

s

hr

1

10

-10

%

K_TTC

V_{TTC_LOW}

I_TTC

5.6

0.33

50

min/nF

V

TTC Low Threshold

TTC falling

TTC Source/Sink Current

TTC Oscillator High Threshold

TTC Oscillator Low Threshold

Battery Switch (BATFET) Driver

BATFET Turn-Off Resistance

BATFET Turn-On Resistance

45

55

µA

V

V_{TTC_OSC_HI}

V_{TTC_OSC_LO}

1.5

1.0

V

R_{DS_BAT_OFF}V_AVCC> 5V

200

10

Ω

R_{DS_BAT_ON}

V_{BATDRV_REG}

t_{BATFET_DEG}

V_AVCC> 5V

kΩ

V_{BATDRV_REG}= V_ACN- V_BATDRVwhen V_AVCC> 5V

and BATFET is on

BATFET Drive Voltage

5.1

6.4

V

BATFET Power-Up Delay to Turn Off

BATFET after Adapter is Detected

30

ms

AC Switch (ACFET) Driver

ACDRV Charge Pump Current Limit

Gate Drive Voltage on ACFET

I_ACFET

V_ACDRV- V_CMSRC= 5V

160

5.6

µA

V

V_{ACDRV_REG}V_ACDRV- V_CMSRCwhen V_AVCC> V_UVLO

R_{ACDRV_LOAD}

5.4

20

Maximum Load between ACDRV and CMSRC

kΩ

SG Micro Corp

www.sg-micro.com

MARCH 2023

9

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

ELECTRICAL CHARACTERISTICS (continued)

(T_J= -40℃ to +85℃, 4.5V ≤ V_PVCC, V_AVCC≤ 22V (referred to AGND), typical values at T_J= +25℃, unless otherwise noted.)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

AC/BAT Switch Driver Timing

Dead time when switching between ACFET

and BATFET

Driver Dead Time

t_{DRV_DEAD}

10

µs

Battery Detection

Wake Timer

t_WAKE

I_WAKE

t_DISCH

I_DISCH

I_FAULT

Max time charge is enabled

R_SENSE= 10mΩ

500

250

1

ms

mA

s

Wake Current

100

400

Discharge Timer

Max time discharge current is applied

Discharge Current

Fault Current after a Time-Out Fault

9.5

2

mA

Wake Threshold with Respect to V_REGto

Detect Absent during Wake

Discharge Threshold to Detect Battery

Absent during Discharge

V_WAKE

V_DISCH

Measure on SRN (SGM41526)

100

2.9

mV/cell

V/cell

Internal PWM

PWM Switching Frequency

f_SW

1200

1600

30

1800

kHz

ns

Dead time when switching between LSFET

and HSFET no load

Driver Dead Time ⁽¹⁾

t_{SW_DEAD}

High-side MOSFET On-Resistance

Low-side MOSFET On-Resistance

R_{DS_HI}

R_{DS_LO}

V_BTST- V_SW= 4.5V

29

33

55

65

mΩ

V

_BTST- V_SWwhen low-side refresh pulse is

2.8

requested, V_AVCC= 4.5V

Bootstrap Refresh Comparator Threshold

Voltage

V_{BTST_REFRESH}

V

V_BTST- V_SWwhen low-side refresh pulse is

requested, V_AVCC> 6V

Internal Soft-Start (8 Steps to Regulation Current I_CHG

)

Soft-Start Steps

SS_STEP

t_{SS_STEP}

8

step

ms

Soft-Start Step Time

1.6

3

Charger Section Power-Up Sequencing

Delay from ISET above 120mV to Start

Charging Battery

t_{CE_DELAY}

1.5

s

Integrated BTST Diode

Forward Bias Voltage

V_F

V_R

0.85

V

I_F= 120mA at +25℃

I_R= 2μA at +25℃

Reverse Breakdown Voltage

Logic IO Pin Characteristics (STAT, CELL)

STAT Output Low Saturation Voltage

21

V_{OUT_LO}

V_{CELL_LO}

Sink current = 5mA

0.6

2.5

V

CELL Pin Input Low Threshold, 4-Cell

(SGM41526)

CELL Pin Input Mid Threshold, 2-Cell

(SGM41526)

CELL pin voltage falling edge

0.3

2.7

V_{CELL_MID}

V_{CELL_HI}

CELL pin middle level voltage

CELL pin voltage rising edge

0.7

V

CELL Pin Input High Threshold, 3-Cell

NOTES:

1. Specified by design.

2. The minimum current is 250mA on 10mΩ sense resistor.

SG Micro Corp

www.sg-micro.com

MARCH 2023

10

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

TYPICAL PERFORMANCE CHARACTERISTICS

Efficiency vs. Charge Current

100

95

90

85

80

75

70

100

95

90

85

80

75

70

V_IN= 15V, 3 Cells, V_BAT= 11.4V

_IN= 15V, 2 Cells, V_BAT= 7.6V

V_IN= 5V, 1 Cell, V_BAT= 3.8V

V_IN= 9V, 1 Cell, V_BAT= 3.8V

V

0

1000

2000

3000

4000

0

1000

2000

3000

4000

Charge Current (mA)

Power-Up

Current Soft-Start

V_IN= 15V, 2 Cells, V_BAT= 0V, V_ISET= 0V

V_IN= 15V, 2 Cells, V_BAT= 7.6V

V_AVCC

V_SW

V_VREF

V_ACDRV

I_CHG

STAT

Time (20ms/div)

Time (5ms/div)

Charge Enable by ISET

Charge Disable by ISET

V_IN= 15V, 2 Cells, V_BAT= 7.6V

V_ISET

V_REGN

STAT

V_SW

I_L

Time (200ms/div)

Time (2µs/div)

SG Micro Corp

www.sg-micro.com

MARCH 2023

11

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

TYPICAL PERFORMANCE CHARACTERISTICS (continued)

Continuous Conduction Mode Switching

Discontinuous Conduction Mode Switching

V_IN= 15V, 2 Cells, V_BAT= 7.6V, I_CHG= 2A

V_IN= 15V, 2 Cells, V_BAT= 9V, I_CHG= 0.15A

V_SW

I_L

V_SW

I_L

Time (200ns/div)

BATFET to ACFET Transition During Power-Up

System Load Transient (Input Current DPM)

V_IN= 15V, 2 Cells, V_BAT= 0V

V_IN= 20V, 1 Cell, V_BAT= 3.8V

V_AVCC

I_IN

V_ACDRV

V_SYS

I_SYS

I_CHG

V_BATDRV

Time (10ms/div)

Time (100µs/div)

Battery-to-Ground Short Protection

Battery-to-Ground Short Transition

V_IN= 15V, 3 Cells, V_BAT= 11.4V

V_SRN

V_SW

I_L

Time (2ms/div)

Time (10µs/div)

SG Micro Corp

www.sg-micro.com

MARCH 2023

12

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

TYPICAL PERFORMANCE CHARACTERISTICS (continued)

Battery Insertion and Removal

V_IN= 15V, 3 Cells, V_BAT= 11.4V

V_SRN

V_SW

I_L

Time (500ms/div)

SG Micro Corp

www.sg-micro.com

MARCH 2023

13

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

FUNCTIONAL BLOCK DIAGRAM

VREF

12

Thermal PAD

CE

VREF

LDO

REGN

LDO

4

AVCC

20

REGN

3.3V

+

UVLO

21

2

BTST

PVCC

Refresh

V_SRN+ 90mV

SLEEP

6

3

ACP

+

20×

20 × I_AC

+

5

ACN

17

ACSET

1

SW

EA &

PWM Control

Driver

Fast/Pre-

CHRG

24

13

ISET

I_{BAT_REG}

Selection

LOWV

+

22

23

PGND

16

15

SRP

SRN

+

20×

20 × I_CHG

Thermal

Regulation

SRN

CELL

(SGM41526)

FB

2.1V

SGM41526

SGM41527

14

+

OCP

UCP

OTP

(SGM41527)

+

BAT_OVP

2.184V

Charge

20 × I_CHG

1.36V

Termination

+

10% × V_ISET

+

LOWV

SLEEP

UVLO

2V

2.03V

+

BAT_SHORT

RECHG

V_SRN

VREF

Battery

Detection

Timer Fault

Charge

Control

Logic

Safety Timer

11

TTC

+

ACOV

ACUV

SUSPEND

OVPSET 18

+

10

TS

1.6V

V_ISET

120mV

+

0.494V

CE

+

9

STAT

ACDRV

Charge Pump

8

7

ACDRV

CMSRC

SLEEP

ACN-SRN

UVLO

V_SRN+ 180mV

V_ACN

+

System

Power

Selector

Control

ACOV

SGM41526

SGM41527

19 nBATDRV

ACUV

Figure 2. Functional Block Diagram

SG Micro Corp

www.sg-micro.com

MARCH 2023

14

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

DETAILED DESCRIPTION

The SGM41526 and SGM41527 are Li-Ion and Li-polymer

fixed-frequency synchronous PWM battery chargers with

integrated switching power MOSFETs. Using external

switches, power path management is provided along with

accurate regulation of the input current, charge current and

battery voltage. The internal block diagram is given in Figure 2.

adjustable charge current is 4A, and with a 20mΩ resistor, it is

2A. If V_ISET= 0.5V and R_SR= 10mΩ, the fast charge current is

I_CHG= 2.5A.

Pulling the ISET voltage down to ground (below 30mV)

disables the charger. To enable the charger, the ISET voltage

should exceed 120mV. The minimum charge current is limited

by the 120mV threshold level. For example, when R_SR

=

Battery Voltage Regulation

10mΩ, the minimum fast charge current is no less than 600mA.

An accurate PWM voltage regulator is used for charge

voltage regulation. For the SGM41526, the number of battery

cells depends on the CELL pin. Two (CELL = floating), three

(CELL = VREF) or four (CELL = AGND) cells can be

connected in series with a fixed nominal voltage of 4.2V per

cell. Table 1 shows the charge regulation voltage in each

case.

As a protective feature, if the device junction temperature

exceeds +120 ℃ , the charge current folds back and is

internally reduced to keep the junction temperature below

+120℃.

Pre-Charge Phase

If the battery voltage is lower than V_LOWVwhen the device is

powered up, the charge will start with a small pre-charge

current to safely recover the battery from deep discharge

state. If the battery voltage still does not exceed the V_LOWV

threshold after 30 minutes, charging will stop, and fault status

will be declared by the status pins. V_LOWVis typically 2.9V/cell

for SGM41526 and 1.46V on FB pin for SGM41527. The

pre-charge current is determined by the fast charge current

as a ratio of 10%:

Table 1. Defining Number of Battery Cells for SGM41526

CELL Pin Voltage

Floating

Charge Regulation Voltage

8.4V (2 Cells)

VREF

12.6V (3 Cells)

AGND

16.8V (4 Cells)

For the SGM41527, the regulation voltage is adjustable. The

FB voltage is compared to an internal 2.1V voltage reference

like a conventional voltage regulator. The regulation voltage

can be adjusted by using an external resistor divider on the

battery voltage (output voltage). Connect the center point of

the resistor divider to the FB pin. The battery regulation

voltage (V_BAT) in the SGM41527 is calculated by Equation 1:

V

ISET

(3)

I_PRECHARGE

=

200×R_SR

The deglitch time of fast charge and pre-charge transition is

25ms.





R

Typical Charge Cycle



¹

(1)

V_BAT= 2.1V × 1+

R₂





Figure 3 shows a complete charge cycle profile (battery

voltage and current versus time) with all the three phases

followed by a typical discharge and auto recharge. The

charge is started assuming that the battery is in a deep

discharge state (low battery voltage). After termination and

stopping the charge, the battery is normally discharged by

system loads. When the voltage falls below the recharge

threshold, another cycle is initiated from fast charge, to bring

the battery back to the full charge state. A new charging cycle

begins when any of the following conditions is met:

where

• R₁is connected between the battery positive terminal and

FB.

• R₂is connected between FB and AGND.

Battery Current Regulation

The maximum charging current for fast charge is set by the

ISET input. Connect battery current sense resistor (R_SR

)

between SRP and SRN. The equation for charge current is

given by:

• The SRN pin voltage falls below the recharge threshold (V_RECH).

• A power-on-reset (POR).

V

ISET

(2)

I_CHG

=

• Disable and enable charge by pulling ISET pin below 30mV

and then above 120mV, respectively.

20×R_SR

The maximum of the full-scale SRP-SRN differential voltage

is 40mV, and it determines the maximum charge current

selected by ISET. The maximum valid input voltage of ISET is

0.8V. For example, with a 10mΩ sense resistor, the maximum

Depending on the battery voltage, the charge is started with

the proper phase. Charge sequence details will be explained

in the next sections.

SG Micro Corp

www.sg-micro.com

MARCH 2023

15

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

DETAILED DESCRIPTION (continued)

Pre-Charge Current

Regulation Phase

Fast Charge Current

Regulation Phase (CC)

Fast Charge Voltage

Regulation Phase (CV)

Termination

Discharge

Auto Recharge

V_REG

I_CHG

V_RECH

Charge

Current

Battery

Voltage

V_LOWV

10%I_CHG

Fast Charge Safety Timer

One Complete Charge Cycle

Pre-Charge

Timer

Termination

Discharge

Auto Recharge

Figure 3. Typical Charge and Discharge Profile

Regulation of the Input Current

cycle will be terminated if the battery is fully charged that is

detected when charge voltage exceeds recharge threshold

(V_RECH) and charge current falls below termination current

threshold (I_TERM). Charge voltage is sensed on the SRN pin of

the SGM41526 and on the FB pin of the SGM41527.

Recharge voltage threshold (V_RECH) is a little bit lower than

the regulation voltage and the termination current threshold

(I_TERM) is equal to 10% of the programmed fast charge current

as given in Equation 5:

The input current is used to power the system and to charge

the battery. System current may vary from zero to maximum

load. With dynamic power management (DPM) capability, the

adapter does not need to be designed for maximum power

demand for both charge and system at the same time.

Otherwise it will lead to a bulky AC adapter and relatively

higher cost. With DPM, the charge current is reduced when

the system has high demand for power, such that the input

current is regulated to a predefined maximum. Therefore, the

AC adapter can be designed for lower power that results in

smaller adapter size and cost.

V

ISET

(5)

I_TERM

=

200×R_SR

For battery safety, prolonged charging must be avoided, so

time limits are considered for charge phases. For pre-charge

phase, a fixed 30-minute safety timer is employed. For the

fast charge phase, an adjustable timer is used. This timer can

be programmed by a capacitor (C_TTC) connected between the

TTC and AGND pins based on Equation 6:

Input current regulation level of DPM is programmed by the

voltage on ACSET pin and the input shunt resistor R_AC, as

given in Equation 4:

V_ACSET

(4)

I_DPM

=

20×R_AC

t_TTC(min) = C_TTC(nF) × K_TTC(min/nF)

(6)

The sense voltage across R_AC(typically 10mΩ) is sent to ACP

and ACN pins. The regulation accuracy can be improved with

larger sense resistor but at the cost of lower efficiency.

where K_TTCis a constant typically equal to 5.6min/nF.

Connecting TCC pin to AGND disables both termination and

fast charge timers. Connecting TCC pin to VREF disables the

safety timer only and termination timer remains functioning.

Termination, Recharge and Timers

In the constant voltage charging phase, the device also

detects the charging current and battery voltage. The charge

SG Micro Corp

www.sg-micro.com

MARCH 2023

16

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

DETAILED DESCRIPTION (continued)

Device Power-Up

• REGN and VREF pins are at their normal voltage levels

without overloading.

The device power pin (AVCC) can be supplied by the battery

or the adapter. If AVCC voltage falls below UVLO threshold,

the device remains disabled. If AVCC voltage exceeds UVLO

threshold, the device is enabled and another comparator

(charger sleep comparator) checks the AVCC voltage to

identify the power source. If the adapter is detected and the

AVCC voltage exceeds the SRN voltage (battery voltage), the

charger exits the sleep mode and can be enabled for

charging. If the AVCC voltage is lower than SRN, the charger

enters the low quiescent current sleep mode to minimize

power taken from the battery. In the sleep mode, the STAT pin

goes to high-impedance state and VREF output is turned off.

The device remains charging until the battery is fully charged

(normal termination), unless the charge is disabled when

V_ISET< 30mV or when any of the above conditions is not

fulfilled during the charge.

Power Path Selection

The SGM41526 and SGM41527 can automatically select the

input adapter or battery as power source for the system. By

default, the system is powered from the battery during device

power-up or in sleep mode. The device can exit sleep mode if

a qualified adapter is plugged in. Then the BATFET is turned

off and the back-to-back MOSFET pair on the power input is

turned on with a protective break-before-make logic so that

system is connected to adaptor. The ACFET turns on after

10μs dead time when BATFET is turned off, so that it avoids

direct input to battery short that can cause over-current

through the selector switches.

AVCC Input Under-Voltage Lockout (UVLO)

Usually the system cannot properly operate if AVCC voltage

is too low (under-voltage). Therefore the device is enabled

until AVCC voltage exceeds a minimum level (UVLO). All

circuits on the IC are disabled if AVCC falls below UVLO

threshold, regardless of the source of power.

Both gates of the back-to-back MOSFET pair on the power

input are driven by the ACDRV pin. The sources are

connected together to the CMSRC pin (Figure 1). The drain of

the RBFET (Q2) is connected to the ACP pin. Q2 is for

reverse discharge protection to avoid current flow from the

battery to the input source. Low R_DS(ON)switches are

recommended for Q1 and Q2 to minimize conduction losses

and heat generation. ACFET (Q1) can control the connection

of adapter to system and battery. This switch also limits the

inrush current rise/fall rate (di/dt) when input adapter is

connected to the system by controlling the turn-on time.

Input Over-Voltage/Under-Voltage Protection

The SGM41526 and SGM41527 provide over-voltage (OV)

and under-voltage (UV) protections to avoid system damage

due to high or low input supply voltage. The input is qualified

if input voltage is within the UV and OV window. The ACOV

and ACUV comparators monitor the OVPSET voltage. If it

exceeds 1.6V (for OV) or falls below 0.494V (for UV), the

charge will be disabled and both input switches (Q1 and Q2)

will be turned off to disconnect the system from the power

supply. A resistor divider from input source can be used to

define the input qualification window. Unlike UVLO that acts

on AVCC (powered from input supply or battery), the OV and

UV protections act only on the input power supply.

The BATFET (P-channel, Q3) controls the connection of

battery and system. Its gate is driven by nBATDRV pin and its

source is connected to system.

The ACFET remains off, as long as a qualified voltage is not

detected, by applying zero gate-source voltage. ACFET

separates the adapter from system.

Charge Enable and Disable

If all following conditions are fulfilled, a charge will be started:

• V_ISET> 120mV (enable charge).

If the device is not in UVLO and system voltage is at most

0.18V above the battery, the BATFET remains on by applying

-5.9V to the gate-source through the nBATDRV pin (gate

voltage clamps to ground if the system voltage is less than

5.9V). The conditions can be represented as:

• V_AVCC> V_UVLO(device not in UVLO).

• V_AVCC> V_SRN(charger not in sleep mode).

• 0.494V < V_OVPSET< 1.6V (qualified power input).

• Not in Thermal Shutdown (T_SHUT).

• No TS fault (battery temperature not too hot or cold).

• Detect battery presence.

• V_AVCC> V_UVLO(not in UVLO).

• V_ACN< V_SRN+ 180mV.

• ACFET is turned on.

• TTC or pre-charge timers are not expired.

The source pin of the BATFET is connected to the system,

ACN pin and PVCC.

SG Micro Corp

www.sg-micro.com

MARCH 2023

17

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

DETAILED DESCRIPTION (continued)

If the input voltage is qualified and AVCC voltage is at least

0.21V above SRN (battery), the device can exit the sleep

mode and transfer the system from battery to adapter. With

the break-before-make logic, there is a 10μs dead time

between input MOSFET pair and BATFET. At first the

BATFET is turned off to disconnect battery from system by

pulling up the nBATDRV voltage to ACN pin. Then the ACFET

is turned on with a 5.6V gate drive voltage between the

Internal Charge Current Soft-Start

The charge current automatically soft starts when fast charge

mode begins to limit the stress on the converter components

due to the current overshoots. During the soft-start, a total of

8 current levels are available for the programmed regulation

current with an evenly spaced step. Each step lasts almost

1.6ms, for a typical soft-tart rise time of 12.8ms. This function

is designed inside the device and no external components are

required.

ACDRV and CMSRC pins, which is provided by an internal

charge pump. The conditions for connecting the adapter to

the system can be represented as follows:

Charge Over-Current Protection

The high-side MOSFET current in the converter is always

monitored by a sense FET and if it exceeds the MOSFET

current limit (typically 10A), the high-side MOSFET is turned

off until the next cycle.

• V_ACUV< V_OVPSET< V_ACOV.

• V_AVCC> V_SRN+ 210mV.

When any of above conditions is no longer valid, ACFET is

turned off and the device enters the sleep mode. BATFET

remains off until the system voltage falls close to SRN

(battery voltage). Then the BATFET turns on and connects

the battery and system. An internal regulator drives

nBATDRV pin to ACN - 5.9V to turn on BATFET.

There is another over-current protection for charge current.

When it exceeds 180% of the programmed value, the

high-side MOSFET is also turned off until the current falls

below the threshold.

Asymmetrical gate driving is used for fast turn-off and slow

turn-on of the ACFET and BATFET. This will allow smooth

transitions and soft connection of the system to the supply

line. Turn-on delay can be increased by adding capacitance

between the gate and source of the switches.

Charge Negative Current Protection

When the battery is charged, the inductor current reduces

and may become negative. This negative current means that

the battery feeds energy to input through converter (it is

called Boost effect). The Boost effect can cause over-voltage

on the input circuit and AVCC, which can damage the input

components, device itself and the system. To prevent the

boosting and negative charge current, the low-side switch

should be turned off before the current drops to zero. The

device senses the charge current by the voltage of the

SRP-SRN, and if it falls below 5mV, the low-side switch is

turned off for the rest of the switching cycle. This leads to

discontinuous conduction mode (DCM) operation of the

converter. Keeping low-side switch off limits the charging of

bootstrap capacitor that feeds the high-side switch gate driver.

A comparator always checks the high-side driver supply

voltage, and if it falls below 2.8V the low-side switch is turned

on for a short period to refresh and recharge the bootstrap

capacitor voltage. This protection overrides the negative

charge current protection.

Charge Converter

The charge converter in SGM41526/7 is a 1.6MHz PWM

step-down regulator. The fixed switching frequency makes

the filter design simple under all input/output or temperature

conditions. Pulse skipping occurs if the duty cycle is

approximately 97%. A type III compensation network is

designed inside so that the use of low ESR ceramic

capacitors on the output is allowed. The compensated error

amplifier output is compared with 1.6MHz sawtooth ramp

voltage to generate PWM wave. The sawtooth amplitude is

proportionally adjusted to the AVCC voltage (input

feedforward) to compensate the impact of the input voltage

variations on the loop gain and simplify the loop

compensation.

SG Micro Corp

www.sg-micro.com

MARCH 2023

18

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

DETAILED DESCRIPTION (continued)

Battery Detection

SRN voltage falls below recharge threshold. If the battery

voltage does not fall below the battery LOWV threshold in 1s,

the battery is detected as present so the 9.5mA sink is turned

off and the charge starts. During the 1s period, the 9.5mA

discharge current is disabled as long as the battery voltage

falls below battery LOWV threshold. Then the converter

generates a small charge current to charge the SRN pin. The

charge current is 250mA typically with 10mΩ sense resistor.

Now, if 0.5s timer times out and the battery voltage exceeds

the recharge threshold, the detection is no-battery and the

process will restart from beginning to detect insertion of the

battery. If after the 0.5s period, the voltage does not exceed

the recharge voltage threshold, the battery is detected as

present and the proper charging phase will start.

Battery presence detection is important and specially needed

for the applications with removable batteries. The SGM41526

and SGM41527 use a reliable detection method for battery

absence, battery insertion and battery removal. This detection

procedure runs during power-up or when the battery voltage

is lower than the recharge threshold. A low voltage on SRN

pin (that connects to battery) can be detected due to battery

discharge or battery removal. The detection process is

designed such that the large capacitors on the charger output

are not detected as battery. The detection flow chart is given

in Figure 4.

Battery detection starts by applying a 9.5mA sink current

though the SRN pin to the battery at power-up or when the

POR or Recharge

Apply 9.5mA discharge

current, start 1s timer

V_FB< V_LhWV

NO

1s timer expired

YES

NO

YES

Disable 9.5mA

discharge current

Battery Present,

Begin Charge

Enable 250mA charge

current, start 0.5s timer

0.5s timer expired

Battery Present,

Begin Charge

V_FB> V_RECH

NO

YES

Disable 250mA

charge current

Battery Absent

Figure 4. SGM41526 and SGM41527 Battery Detection Flow Chart

Battery

Absent

Battery

Absent

V_{BAT_REG}

V_RECH

Battery

Present

V_LOWV

Figure 5. Timing of the Battery Insertion Detection

SG Micro Corp

www.sg-micro.com

MARCH 2023

19

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

DETAILED DESCRIPTION (continued)

Note that the total output capacitance that appears parallel to

the battery should not be too large such that with the applied

sink or charge currents and timing the no-battery voltage

changes fast and passes the detection thresholds within 1s or

0.5s periods. Equations 7 and 8 can be used to calculate the

maximum output capacitances:

AGND. The charge will be disabled if the over-voltage

condition is not cleared for more than 30ms.

Battery Temperature Qualification

Battery temperature is continuously monitored by measuring

the voltage between the TS pin and AGND that is sensed by a

NTC (negative temperature coefficient) thermistor attached to

the battery pack. A resistor divider from VREF is used to

adjust the temperature limits. The voltage of TS pin is

compared with internal thresholds and charge process will not

begin until the TS pin voltage (which indicates battery

temperature) is within the V_LTFto V_HTFwindow. If during

charge the battery get too hot or too cold and temperature

goes out of the allowed range, the charge will suspend by

turning off PWM switches. The charge resumes automatically

if the temperature returns to the allowed window.

I_DISCH× t_DISCH

C_MAX

=

(for SGM41526)

(7)

(8)

4.1V - 2.9V ×N

(

)

Cell

I_DISCH× t_DISCH

C_MAX

=

(for SGM41527)





R

¹

2.03V -1.46V × 1+

(

)



R₂





where

_MAX= maximum output capacitance.

C

I_DISCH= discharge current.

t_DISCH= discharge time.

Figure 6 illustrates the temperature qualification function and

the thresholds for the charge initiation, suspension and

recovery.

N_Cell= number of cells in the battery.

R₁and R₂: FB pin feedback resistors from the battery.

Temperature Range to

Initiate Charge

Temperature Range during

a Charge Cycle

Example:

VREF

For a 3-cell Li+ charger (12.6V battery voltage regulation),

with R₁= 500kΩ, R₂= 100kΩ, I_DISCH= 9.5mA and t_DISCH= 1s,

the maximum allowed capacitance is:

Charge Suspended

Charge at full C

Charge Suspended

Charge at full C

V_LTF

V_LTFH

V_LTF

V_LTFH

9.5mA ×1s

C_MAX

=

= 2.8mF

(9)

500kΩ

100kΩ







0.57V × 1 +







V_HTF

Therefore, the total capacitance on the battery node should

V_TCO

be less than 2800μF.

Charge Suspended

AGND

Battery Short Protection

Figure 6. Battery Temperature Qualification Function and

Thresholds on the Sensed TS Pin Voltage

During charge, if the battery voltage sensed on the SRN pin

falls below 2V threshold, the battery is considered in short

condition. The charge will quickly stop for a 1ms period

followed by a soft-start toward the pre-charge current level to

prevent over-current and saturation of the inductor. In battery

short condition, the charger operates in nonsynchronous

mode.

The TS pin resistor divider (Figure 7) can be calculated based

on the hot and cold temperature levels recommended for the

battery by Equation 10 and Equation 11:













1

V_VREF× R_THCOLD× R_THHOT

×

-

V_LTFV_TCO

(10)

R_T2

=

Battery Over-Voltage Protection

















V_VREF

V_TCO

V_VREF

V_LTF

R_THHOT

×

- 1 - R

×

- 1



THCOLD

Battery voltage is continuously monitored for over-voltage

protection. If the sensed voltage exceeds 104% of the

regulation voltage, the converter high-side switch remains off.

This protection reacts in one cycle. The over-voltage may

occur due to a battery disconnection or load removal. The

stored energy in the output capacitors is discharged by

sinking a total of 6mA current through SRP and SRN pins to



V_VREF

V_LTF

-1

1

(11)

R_T1

=

1

+

R_T2

R_THCOLD

SG Micro Corp

www.sg-micro.com

MARCH 2023

20

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

DETAILED DESCRIPTION (continued)

Using a 103AT type NTC thermistor in the battery pack and

selecting T_COLD= 0℃ and T_HOT= 45℃ range for Li-Ion or

Li-polymer battery, and recalling the NTC resistances at

temperature limits from datasheet:

Recovery from Timer Fault

If a charge timer fault occurs, the device recovery process will

depend on the battery voltage as follows.

Case 1: If V_BATexceeds the recharge threshold when the

time-out fault occurs, the charge will be suspended firstly.

When the battery voltage falls below recharge threshold, the

battery detection begins again, and then the timer fault is

cleared. The fault will also clear by a power-on-reset (POR) or

by pulling the ISET voltage below 30mV.

R_THCOLD= 27.28kΩ (103AT NTC resistance at 0℃)

R_THHOT= 4.911kΩ (103AT NTC resistance at 45℃)

The resistors can be calculated as:

R_T1= 5.29kΩ

R_T2= 32.12kΩ

Case 2: If V_BATfalls below the recharge threshold when the

timer fault occurs, a small charge current is applied to detect

the battery removal at first. The small charge current is not

removed until V_BATexceeds the recharge threshold. Then the

small charge current is disabled. The rest of recovery process

is as explained in case 1.

The actual temperature range can be calculated based on the

selected standard resistor values and NTC actual

characteristics.

VREF

Design of the Inductor, Capacitor and

Sense Resistor

R_T1

SGM41526/7

For the charger internal compensation, the best stability is

achieved if the LC filter resonant frequency (f_O) given in

Equation 12 is approximately between 15kHz and 25kHz:

TS

1

R_TH

103AT

R_T2

(12)

f_O

=

2π LC

Some typical LC values for various charge currents are given

in Table 2.

Figure 7. Battery Pack Temperature Sensing Network

Table 2. LC Typical Values vs. Designed Charge Current

Charge Current

Output Inductor L

Output Capacitor C

1A

2A

3A

4A

MOSFET and Inductor Protection in Short

Circuit Condition

6.8µH

10µF

3.3µH

20µF

3.3µH

20µF

2.2µH

30µF

The SGM41526 and SGM41527 provide cycle-by-cycle short

circuit protection by monitoring the voltage drop across R_DS(ON)

of the MOSFETs. If a short is detected, the charger will be

latched off, which means the Buck converter is disabled but

the ACFET will not be turned off, and system is still connected

to the adaptor. Latch-off state can only be removed by

unplugging and re-plugging the input power (adapter). The

LED connected to STAT pin blinks at this condition.

STAT Charge Status Output

STAT is an open-drain output that indicates the charger status

as explained in Table 3. This pin can be used for driving LEDs

or informing the host about charge status.

Table 3. STAT Output Pin States

Charge State

STAT Transistor

Thermal Regulation and Shutdown

Charge in Progress (including Recharging)

Charge Completed, Sleep Mode, Charge Disabled

ON

The low thermal impedance of the TQFN package provides

good cooling for the silicon. When the junction temperature

exceeds +120℃, the thermal regulation is triggered. Then the

device will decrease charge current to reduce internal heat

generation. Moreover, if the junction temperature exceeds the

shutdown level (T_SHUT= +150℃), charger is turned off and

will not resume until T_Jfalls below +130℃.

OFF

Charge Suspend, Input Over-Voltage, Battery

Over-Voltage, Timer Fault, Battery Absent

BLINK

SG Micro Corp

www.sg-micro.com

MARCH 2023

21

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

DETAILED DESCRIPTION (continued)

Device Functional Modes

The SGM41526 and SGM41527 can operate independently.

However, some pin settings can be adjusted by an external

controller (like ISET or ACSET). This allows the

implementation of ″battery learn mode″ for applications with

dynamic charging conditions.

The SGM41526 and SGM41527 are stand-alone switching

chargers and power path selectors. They operate from a

qualified adapter or DC supply system. This device is capable

of providing dynamic power management (DPM mode) to

reduce the input loading by sharing the load with the battery

on the peak system demands. Because of DPM capability,

the adaptor size and power rating can be reduced effectively

for the systems with highly dynamic loads.

Figure 8 shows the typical efficiency of a 4A charger for a

2-cell application.

100

V_IN= 15V, 2 Cells

V

_BAT= 7.6V

The gate drive pins for power path selector switches (ACDRV

and CMSRC) control the input NMOS pair, ACFET (Q1) and

RBFET (Q2). The nBATDRV pin controls the gate of the

battery connection PMOS switch (Q3). If the input (adapter) is

qualified, system will be connected to the input by turning Q1

and Q2 on. Otherwise, Q3 will be turned on then the system

is powered from battery. Moreover, the battery cannot feed

back to the input with power path selection control.

95

90

85

80

75

70

DPM capability is included in the SGM41526 and SGM41527

to limit maximum power taken from the input (adapter) by

reducing the charge current when the system power demand

is high. Input current is accurately sensed to monitor power

usage. Without DPM, the adapter must be designed to

provide maximum charge power plus maximum system power.

However, with DPM, the adapter can be designed for

significantly lower power rating that reduces the size and cost

of the adapter.

0

1000

2000

3000

4000

Charge Current (mA)

Figure 8. Typical Charge Efficiency

SG Micro Corp

www.sg-micro.com

MARCH 2023

22

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

APPLICATION INFORMATION

SGM41526 and SGM41527 can be used in portable

applications with up to 4-cell Li-Ion or Li-polymer batteries.

The SGM41526 accurately regulates the battery voltage at a

fixed 4.2V/cell value (minimum 2 cells) and with low leakage

from battery. Number of cells is programmable by CELL pin.

For the applications that need custom battery regulation

voltage or use only one cell, the SGM41527 can be used. In

this variant, the battery regulation voltage is adjustable

through the FB pin similar to a conventional voltage regulator.

Figure 9 shows a typical application circuit of the SGM41526

with a 2-cell battery (8.4V).

Design Requirements

As an example to explain the design procedure, suppose that

a charger is needed with the parameters listed in Table 4.

Table 4. Design Requirements

Parameter

Input Voltage Range

Input Current DPM Limit

Battery Voltage

Example Value

4.5V to 22V

600mA (MIN)

18V (MAX)

Charge Current

4A (MAX)

For power input, an adapter or power supply from 4.5V to 22V

is needed generally. The minimum voltage range depends on

the number of battery cells. Typically, the adapter current

rating should be 500mA and higher.

The maximum battery voltage shows that a 4-cell battery is

considered in the design.

R_AC

10mΩ

Q1

Q2

I_IN

V_IN

I_OUT

12V

Adapter

Input

V_SYS

System

R_IN

2Ω

C₁₁

0.1μF

C₄

10μF

C₁₂

0.1μF

ACN PVCC

nBATDRV

C₁₄

R₁₅

47nF 499kΩ

R₁₂

4.02kΩ

C₁₃

4.7nF

ACP

CMSRC

C_IN

2.2μF

R₁₄1kΩ

Q3

R₁₁

4.02kΩ

L

R_SR

10mΩ

ACDRV

3.3μH

V_BAT

C₁₀

R₆1MΩ

SW

OVPSET

R₇

100kΩ

R₁10Ω

C₉

C₅

0.047μF

D1

D2

C₈

0.1μF

SGM41526

D4

10μF 10μF

V_BAT

BTST

AVCC

C₁

1μF

I_BAT

REGN

C₆

V_REF

1μF

VREF

ISET

R₄

R₂

232kΩ

PGND

100kΩ

C₇

0.1μF

R_T

R₃

103AT

SRP

SRN

32.4kΩ

V_REF

R₈

5.23kΩ

ACSET

CELL

C₂

1μF

R₅

22.1kΩ

Floating

TS

R₁₀

1.5kΩ

C₃

0.1μF

R₉

30.1kΩ

Thermal

Pad

TTC

STAT

(AGND)

D3

NOTE: 12V input, 2-cell battery 8.4V, 2A charge current, 0.2A pre-charge/termination current, 3A DPM current, 17.6V input OVP, 0℃ to 45℃ TS.

Figure 9. Typical SGM41526 Schematic for a 2-Cell Battery Application

SG Micro Corp

www.sg-micro.com

MARCH 2023

23

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

APPLICATION INFORMATION (continued)

Inductor Selection

Input Path Capacitors

Small inductors and capacitors can be used in this design due

to the high switching frequency of the device (f_SW= 1.6MHz).

The inductor should not saturate at the highest current that

occurs at maximum charge current plus half peak value of the

ripple current as given in Equation 13:

The input capacitors carry two types of AC currents: (1) the

converter switching ripple currents and (2) the high frequency

(HF) transient currents of the switching. High frequency

decoupling capacitors are necessary to prevent voltage

ringing due to HF currents. Usually some bulk capacitance is

needed to avoid large input rail voltage ripples. Typically, a

ceramic capacitor placed close to the switching leg (PVCC

and PGND) is sufficient to circulate the switching frequency

and high frequency AC currents. This capacitor needs to have

low ESR and ESL. The capacitor self-resonance frequency

should be selected well above switching frequency.

Otherwise, it will not be able to bypass HF switching transient

currents and large ringing noise may be seen on the PVCC. A

combination of smaller size and larger size capacitors may be

used for better noise suppression. Stable ceramic capacitors

such as X5R or X7R are recommended. All capacitors should

be able to carry the peak RMS current of the ripples. Input

capacitor ripple current (I_CIN) can be calculated from Equation

16:

I_SAT≥ I_CHG+ (1/2)I_RIPPLE

(13)

where I_CHGis the charging current, and I_RIPPLEis the ripple

current magnitude (peak-to-peak of the AC component).

Except for light loads, the inductor current is continuous and

the I_RIPPLEis determined by the following equation:

V ×D 1-D

(

)

IN

(14)

I_RIPPLE

=

f_S×L

where V_INis the input voltage, D = V_OUT/V_INis duty cycle, and

L is the inductance value.

Usually the highest ripple current is generated when duty

cycle is equal to or near 0.5. Inductor current ripple is typically

chosen to be 20% to 40% of the full load DC current to get a

reasonable compromise between inductor size and AC losses.

Higher ripple results in smaller inductor but with lower

efficiency. The highest input voltage and charge current ranges

should be considered for inductor design. Consider 30%

ripple for this design (I_RIPPLE≤ 0.3I_CHG):

I_CIN= I_CHG

× D× 1-D

(

)

(16)

The highest ripple occurs at D = 0.5 and the worst case RMS

ripple current is 0.5I_CHG(2A for this example).

Due to the capacitance drop at higher DC voltage bias and

aging, a good margin should be considered for selection of

the capacitor voltage rating. For a 20V maximum input, a 25V

capacitor works. However, a 35V or higher voltage capacitor

is recommended. For a high current (3A ~ 4A) charger, a

minimum of 20μF input capacitance is recommended. For

lower currents (1A or less), 10μF capacitance is sufficient.

22V ×0.5× 1- 0.5

(

)

0.3× 4A ≥

(15)

1.6MHz ×L

Or L ≥ 2.9μH.

The initial tolerance of the commercial inductors is usually

quite large (typically 10% - 20% and in some cases as high as

30%). The inductance also drops with higher currents

(typically in the order of 20% at maximum current). Therefore,

a good margin must be considered for selection of the

inductor value by consideration of the initial tolerance,

thermal and maximum current drops from the inductor

datasheet. For this example, a 3.3μH inductor is considered.

Output Capacitor Selection

Applying a charge current with high ripple will deteriorate the

battery lifetime and generate extra loss and heat. Therefore, it

is important to bypass the inductor ripple using output

capacitors and to keep the voltage ripple low, allowing only

the DC current to flow and charge the battery. The output

capacitors should have enough RMS current rating to carry

the worst-case current ripples. The output RMS current (I_COUT

can be calculated as:

L = 3.3μH (nominal value of the inductor)

)

The minimum inductor saturation current from Equation 13 is:

1

2





I_SAT≥ 4A +

×0.3× 4A → I_SAT≥ 4.6A

I_RIPPLE









(17)

I_COUT

=

≈ 0.29×I_RIPPLE

2× 3

Inductor core type and form factor can be designed based on

the required size, loss, magnetic noise coupling, cost, stock

availability and reliability considerations.

The output ripple is given by Equation 18:



₂









V_OUT

(18)

∆V_O

=

1-

8LCf_S

V

IN

SG Micro Corp

www.sg-micro.com

MARCH 2023

24

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

APPLICATION INFORMATION (continued)

The ripple can be reduced by decreasing the cut-off

1

equivalent ESR for damping of hot plug-in spikes. R_iand R_a

should have sufficient package size and power rating to

dissipate inrush current losses without overheating. A final test

is recommended to assure all requirements are satisfied in the

worst conditions and to make the necessary adjustments.

frequency of the LC filter (f_r=

). The SGM41526 and

2π LC

SGM41527 internal loop compensator is designed for a

cut-off frequency of 15kHz to 25kHz. Therefore, in order to

achieve good loop stability, select the output capacitor such

that LC filter cut-off frequency is in the specified range. Stable

ceramic capacitors (like X5R or X7R) are recommended with

enough margin for the rated voltage (25V or higher).

Selecting C_OUT= 20μF (two parallel 10μF) will result in f_r=

19.6kHz with the selected L = 3.3μH inductor.

D₁

R_i

2Ω

R_a

4.7Ω ~ 30Ω

(1206)

AVCC

AGND

(2010)

Adapter

Input

C_i

2.2μF

C_a

0.1μF ~ 1μF

Input Filter Design

Most portable applications must be able to handle hot adapter

plug-in and removal. The parasitic line inductance of the

adapter and the input capacitors of the charger form a

Figure 10. Input Filter

second-order LC circuit that may create

a transient

over-voltage on the AVCC and damage the device. So careful

design of the input filter with proper damping is important to

assure the voltage peaks are well below the device limit. A

common method is using a high ESR electrolytic input

capacitor to damp the over-voltage spike. A TVS Zener diode

with high current capability may also be used on the AVCC

pin to clamp the transient peaks. If a more flexible and

compact solution is needed, the input filter shown in Figure 10

can be used. In this network, R_iC_ifilter damps the hot-plug

oscillations and limits the over-voltage spikes to a safe level.

D₁provides reverse voltage protection if a reverse polarity

adapter is mistakenly connected or when the battery is also

feeding AVCC. C_ais the decoupling capacitor of the AVCC that

is placed right beside the AVCC and AGND pins. R_aC_afilter

provides more damping and reduction of the dv/dt and

magnitude of voltage spike. R_aalso serves as a current limiter.

C_ais typically less than the C_i, so R_idominates in the total

Selecting Input Switch Pair (ACFET and

RBFET)

Low R_DS(ON), N-type MOSFETs are used for ACFET(Q1) and

RBFET(Q2) as shown in Figure 11. Due to the relatively large

amount of capacitance on the system power rail, PVCC and

charger output, a large inrush current can flow in the switches

if it is not managed properly. Slow turn-on of Q1 can reduce

the inrush current. MOSFETs with relatively large drain-gate

and gate-source parasitic capacitances (C_GDand C_GS) have

slower turn-on time. External capacitors may be used if Q1

turn-on is not slow enough. As an example, external C_GD

=

4.7nF and C_GS= 47nF can be used across Q1. Current and

power rating of these switches should be selected with good

margin compared to the maximum current from the adapter.

ADAPTER

Q1

Q2

R_SNS

SYS

C_{SY S}

40μF

R_IN

2Ω

C₄

1μF

R_GS

499kΩ

C_GS

R₁₂

4.02kΩ

PV CC

C_GD

C_IN

2.2μF

R₁₁

4.02kΩ

CMSRC

ACDRV

Figure 11. External Capacitors to Slowdown Q1 Turn-On and Limit Inrush Current

SG Micro Corp

www.sg-micro.com

MARCH 2023

25

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

APPLICATION INFORMATION (continued)

Design Examples

R_AC

20mΩ

Q4

I_IN

V_IN

RevFET

20V

Adapter

Input

V_SYSI_OUT

System

C₁₁

0.1μF

C₁₂

0.1μF

ACN PVCC

nBATDRV

C₄

10μF

R₁₂

4.02kΩ

ACP

CMSRC

R₁₁

4.02kΩ

L

R_SR

10mΩ

ACDRV

3.3μH

V_BAT

C₁₀

R₆1MΩ

SW

OVPSET

R₇

78.7kΩ

R₁₁5Ω

C₉

C₅

0.047μF

C₈

0.1μF

SGM41526

D1

10μF 10μF

BTST

AVCC

D2

C₁

1μF

Optional

I_BAT

REGN

C₆

V_REF

1μF

VREF

ISET

R₄

100kΩ

R₂

100kΩ

PGND

C₇

0.1μF

R_T

R₃

103AT

SRP

SRN

32.4kΩ

V_REF

R₈

6.81kΩ

ACSET

CELL

C₂

1μF

R_5B

R_5A

TS

8.06kΩ 32.4kΩ

R₉

133kΩ

R₁₀

1.5kΩ

Thermal

TTC

ILIM_500mA

Pad

STAT

(AGND)

D3

NOTE: Adapter input 20V OVP 22V, up to 4A charge current, 0.4A pre-charge current, 2A adapter current or 500mA USB current,

5℃ to 40℃ TS, system connected before sense resistor.

Figure 12. Typical Application Schematic with 4-Cell Unremovable Battery (OVP 20V)

R_AC

10mΩ

Q1

Q2

I_IN

V_IN

I_OUT

15V

Adapter

Input

V_SYS

System

R_IN

2Ω

C₁₁

0.1μF

C₄

10μF

C₁₂

0.1μF

ACN PVCC

nBATDRV

C₁₄

R₁₃

47nF 499kΩ

R₁₂

4.02kΩ

C₁₃

4.7nF

ACP

CMSRC

C_IN

2.2μF

R₁₄1kΩ

Q3

R₁₁

4.02kΩ

L

R_SR

10mΩ

ACDRV

2.2μH

V_BAT

R₆499kΩ

SW

OVPSET

R₇

49.9kΩ

R₁₀

49.9kΩ

C₉

C₁₀

C₅

0.047μF

Battery Learn

V_REF

C₈

0.1μF

D4

20μF 10μF

Learn

BTST

R₁₅

599kΩ

FB ₊

R₁

I_BAT

REGN

499kΩ

C₆

1μF

R₁₆

499kΩ

SGM41527

R₂

PGND

100kΩ

C₇

0.1μF

D1

SRP

D2

R₁₇10Ω

V_BAT

AVCC

C₁

1μF

SRN

FB

V_REF

VREF

ISET

R₄

R₁₈

100kΩ

R_T

103AT

R₈

5.23kΩ

100kΩ

R₁₉

32.4kΩ

TS

R₉

30.1kΩ

ACSET

STAT

C₃

0.1μF

C₂

1μF

R₅

32.4kΩ

TTC

R₃

1.5kΩ

Thermal

Pad

(AGND)

D3

NOTE: 15V input, 3-cell battery 12.6V, 4A charge current, 0.4A precharge/termination current, 4A DPM current, 0℃ to 45℃ TS.

Figure 13. A Typical 3-Cell Application Schematic with Battery Learn Function

SG Micro Corp

www.sg-micro.com

MARCH 2023

26

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

APPLICATION INFORMATION (continued)

I_OUT

5V

Adapter

Input

V_SYS

System

I_IN

V_IN

C₄

10μF

ACP

ACN PVCC

nBATDRV

CMSRC

L

ACDRV

R_SR

3.3μH

20mΩ

V_BAT

R₆400kΩ

SW

OVPSET

C₅

0.047μF

R₇

C₉

C₁₀

C₈

0.1μF

SGM41527

D1

100kΩ

10μF 10μF

R₁₁5Ω

BTST

AVCC

VREF

C₁

1μF

D2

R₁

100kΩ

I_BAT

REGN

V_REF

C₆

1μF

R₂

100kΩ

R₄

100kΩ

PGND

Selectable

C₇

Current Limit

0.1μF

ISET

SRP

SRN

V_REF

R_5B

R_5A

R_T

103AT

C₂

1μF

12.1kΩ 12.1kΩ

R₈

5.23kΩ

FB

ILIM_500mA

TS

ACSET

R₉

30.1kΩ

TTC

R₁₀

1.5kΩ

Thermal

Pad

(AGND)

STAT

D3

NOTE: USB with 8V input OVP, 900mA or 500mA selectable charge current limit, 0℃ to 45℃ TS, system connected after sense resistor.

Figure 14. Typical Application Schematic with Single-Cell Unremovable Battery

Layout Guidelines

capacitors at the point of connection to the device (between

sense traces and between one of them and AGND).

A good PCB layout is critical for proper operation of the

switching circuits. A list of important considerations for

SGM41526 and SGM41527 layout design are provided here:

5. Output capacitors should be placed right next to the sense

resistor.

1. The switching node (SW) creates very high frequency

noises several times higher than f_SW(1.6MHz) due to sharp

rise and fall times of the voltage and current in the switches.

To reduce the ringing issues and noise generation, it is

important to minimize impedance and loop area of the AC

current paths. A graphical guideline for the current loops and

their frequency content is provided in Figure 15.

6. Keep input and output capacitor ground returns tied together

and on the same layer before connecting them to the device

PGND. Having all of them connected in a small geometric

area right beside the device is highly recommended.

7. Keep AGND separated from PGND and connect them only

in a single point under the device body and connect it to the

thermal pad. Use AGND copper pour only under the device. A

0Ω resistor can be used for single point connection of AGND

and PGND. Make connections to AGND with star geometry.

2. Input and other decoupling capacitors must be placed as

close to the device pin and ground as possible with the

shortest copper trace and on the same layer of PCB.

8. For proper cooling of the device, use several thermal vias

connecting the thermal pad pour to the GND plane on the

opposite side and other layers of the PCB. Use enough solder

for thermal pad connections. Open via holes allow solder to

penetrate to the other side and provide low thermal resistance.

Apply solder to the opposite side thermal ground for better

connection to the vias and better thermal cooling. Thermal

ground should not be connected to PGND planes.

3. Surface area of the SW node should be minimized to

reduce capacitive HF noise coupling. Use a short and wide

track connection to the inductor on the same layer of PCB.

Keep sensitive and high impedance traces away from

switching node and trace.

4. Place the charge current-sense resistor right next to the

inductor and use the same layer of PCB for routing them to

the device amplifier input while keeping them close together

and away from high current paths.

9. Remember that vias add some parasitic impedance

(resistive/inductive) to the trace. So, it is generally

recommended to avoid vias in the sensitive or high frequency

paths.

Figure 16 shows the proper Kelvin connection of shunt

resistors for accurate current sensing. Use decoupling

SG Micro Corp

www.sg-micro.com

MARCH 2023

27

SGM41526

SGM41527

1.6MHz Synchronous Li-Ion/Li-Polymer Stand-Alone

Battery Chargers with Automatic Power Path Selector

APPLICATION INFORMATION (continued)

(I_AC≈ 0)

L

SW

HF Noise

DC IN

Coupling

Current Path

Containing Very

High Frequency

and Switching

Frequency

Current Path for

Ripple Current

BAT

C

(Switching Frequency

and the Low Order

Harmonics)

C_IN

PGND

Keep these PGND points

close together

Figure 15. Graphical Representation of the Switching and Transient Current Loops, and Capacitive Noise Coupling from

SW Node

Current Direction

R_SNS

Current Sensing Direction

To SRP and SRN Pin

Figure 16. Sensing Resistor PCB Layout

REVISION HISTORY

NOTE: Page numbers for previous revisions may differ from page numbers in the current version.

MARCH 2023 ‒ REV.A.1 to REV.A.2

Page

Changed Pin Description section.....................................................................................................................................................................4, 5

JANUARY 2023 ‒ REV.A to REV.A.1

Page

Added Electrical Characteristics section .................................................................................................................................................... 6, 8, 10

Changes from Original (JULY 2022) to REV.A

Page

Changed from product preview to production data.............................................................................................................................................All

SG Micro Corp

www.sg-micro.com

MARCH 2023

28

PACKAGE INFORMATION

PACKAGE OUTLINE DIMENSIONS

TQFN-5.5×3.5-24L

k

e1

D

N24

N1

N2

N23

D1

E1

E

e

N13

N12

b

L

b1

TOP VIEW

BOTTOM VIEW

4.1

2.7

0.70

2.05

A

6.1

4.7

4.05

A1

0.5

A2

SIDE VIEW

0.25

0.20

1.5

RECOMMENDED LAND PATTERN (Unit: mm)

Dimensions

In Millimeters

Dimensions

In Inches

Symbol

MIN

MAX

0.800

0.050

MIN

0.028

0.000

MAX

0.031

0.002

A

A1

A2

D

0.700

0.000

0.203 REF

0.325 REF

0.008 REF

0.013 REF

3.400

1.950

5.400

3.950

3.600

2.150

5.600

4.150

0.134

0.077

0.213

0.156

0.142

0.085

0.220

0.163

D1

E

E1

k

b

0.200

0.150

0.300

0.250

0.500

0.008

0.006

0.012

0.010

0.020

b1

L

e

0.500 BSC

1.500 BSC

0.020 BSC

0.059 BSC

e1

SG Micro Corp

www.sg-micro.com

TX00122.000

PACKAGE INFORMATION

TAPE AND REEL INFORMATION

REEL DIMENSIONS

TAPE DIMENSIONS

P2

P0

W

Q2

Q4

Q2

Q4

Q2

Q4

Q1

Q3

Q1

Q3

Q1

Q3

B0

Reel Diameter

P1

A0

K0

Reel Width (W1)

DIRECTION OF FEED

NOTE: The picture is only for reference. Please make the object as the standard.

KEY PARAMETER LIST OF TAPE AND REEL

Reel Width

Reel

Diameter

A0

B0

K0

P0

P1

P2

W

Pin1

Package Type

W1

(mm)

(mm) (mm) (mm) (mm) (mm) (mm) (mm) Quadrant

TQFN-5.5×3.5-24L

13″

12.4

3.80

5.80

1.00

4.0

8.0

2.0

12.0

Q1

SG Micro Corp

TX10000.000

www.sg-micro.com

PACKAGE INFORMATION

CARTON BOX DIMENSIONS

NOTE: The picture is only for reference. Please make the object as the standard.

KEY PARAMETER LIST OF CARTON BOX

Length

(mm)

Width

(mm)

Height

(mm)

Reel Type

Pizza/Carton

13″

386

280

370

5

SG Micro Corp

www.sg-micro.com

TX20000.000


型号：	SGM41526
厂家：	Shengbang Microelectronics Co, Ltd
描述：	1.6MHz Synchronous Li-Ion and Li-Polymer Stand-Alone Battery Charger with Automatic Power Path Selector 电池
文件：	总31页 (文件大小：1309K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

SGM41526 [SGMICRO]

相关型号：

SI9130DB

SI9135LG-T1

SI9135LG-T1-E3

SI9135_11

SI9136_11

SI9130CG-T1-E3

SI9130LG-T1-E3

SI9130_11

SI9137

SI9137DB

SI9137LG

SI9122E