MP2617AGL_技术文档

MP2617A, MP2617B

3A Switching Charger with NVDC

Power Path Management

For Single Cell Li+ Battery

DESCRIPTION

FEATURES

The MP2617A / MP2617B is a monolithic

switch mode battery charger with power path

management for single-cell Li-ion batteries in a

wide range of tablet and other portable devices.

It integrates a synchronous BUCK regulator to

provide regulated voltage for powering the

system output and at the same time charging

the battery. This device supports both USB and

high power DC adapter input. In USB mode, the

input current limit can be programmed to

450mA or 825mA via the logic pins to cover the

USB2.0 and USB3.0 specifications. When the

adapter input is present, the input current can

also be limited in order to avoid overloading of

the DC adapter. Input current limit can be

programmed up to 3A.



4V to 10V Operating Input Voltage

Smart Power Path Management

Five Control Loops: Input Current Limit,

Input Voltage Limit, Constant Charge

Current, Terminal Battery Control and

Thermal Fold-Back.

1.6MHz Switching Frequency

Programmable Input Current Limit

Programmable Charge Current



Single Input for USB and AC adapter

Cover

Specification

Fully Integrated Power Switches

USB2.0

and

USB3.0

Input



No External Blocking Diode and Sense

Resistor Required

Charging Operation Indicator

Built-in Programmable Charging Timer

Thermal Limiting Regulation on Chip

Battery Temperature Monitor



The smart power path management allows

MP2617A and MP2617B to regulate the system

voltage for powering an external load and

charging the battery independently and

simultaneously. This allows immediate system

operation even under missing or deeply

discharged battery. When the input current limit

is reached, the system load is satisfied in

priority, then the charger will take the remaining

current to charge the battery. Additionally, the

smart power path control allows an internal

connection from battery to the system in order

to supplement additional power to the load in

the event the system power demand increases

over the input limited power or the input is

removed.

Tiny Package Features Small Size.

APPLICATIONS



Smart Phone

E-Book

GPS

Portable Media Player

Portable Hand-held Solution

Tablet PC

All MPS parts are lead-free, halogen free, and adhere to the RoHS

directive. For MPS green status, please visit MPS website under Quality

Assurance.

“MPS” and “The Future of Analog IC Technology” are Registered

Trademarks of Monolithic Power Systems, Inc.

The MP2617A / MP2617B features high

integration with all the power switches integrate

inside. No external MOSFET, blocking diodes,

or current sense resistor is required.

Two status monitor output pins are provided to

indicate the battery charge status and power

source status. Other features include trickle

charge, battery temperature monitoring, timer

and thermal limiting regulation on chip.

The MP2617A / MP2617B is available in QFN

3mmx4mm package.

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

TYPICAL APPLICATION

ON

OFF

AC adapter

/USB input

VILIM

M0

M1

EN

L

SYS Load

SW

IN

R3

R4

C1

C3

C_SYS

CHGOK

BST

SYS

ACOK

VCC

R1

SYSFB

PGND

R_T1

C_IN

C2

NTC

R2

I_CHG

BATT

vBATT

TMR

AGND

R_T2

C_BATT

C_TMR

R_NTC

ISET

ILIM

MP2617A/B

R_ISET

R_ILIM

0

MP2617A

MP2617B

MP2617 Family Table

Features

Battery Charge Full Voltage

MP2617A

4.35V

MP2617B

4.2V

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

ORDERING INFORMATION

Part Number

MP2617AGL*

MP2617BGL

Package

QFN-20 (3mmx4mm)

Top Marking

MP2617A

MP2617B

* For Tape & Reel, add suffix –Z (e.g. MP2617AGL–Z);

PACKAGE REFERENCE

TOP VIEW

20 19 18 17

1

2

3

4

5

6

16

BST

NTC

15 ISET

SW

IN

14 BATT

13

SW

PGND

SYS

SYSFB

12

11

AGND

EN

7

8

9

10

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

PIN FUNCTIONS

Package

Pin #

Name Description

Bootstrap. A capacitor is connected between SW and BST pin to form a floating supply

across the power switch driver to drive the power switch’s gate above the supply voltage.

1

BST

3

2,4

5

IN

Power input of the IC from adapter or USB.

SW

Switch output.

PGND Power ground.

_____

Function logic control pin of the IC. Logic low to enable the part and logic high to disable the

part.

6

EN

7

8

M0

M1

Mode Select Input Pin, in combination with M1 pin, setting the input current limit mode.

Mode Select Input Pin, in combination with M0 pin, setting the input current limit mode.

_____________

Open drain output. It is pulled low during charging. And it is pulled high through an external

resistor to VCC to indicate charge completed.

9

CHGOK

Open drain output. It is pulled low to indicate the presence of a valid input power supply.

Otherwise, it is pulled high through an external resistor to VCC to indicate invalid input or

removed input.

__________

10

ACOK

11

12

AGND Analog ground.

SYS voltage program pin. Connect a resistor divider from the pin to SYS and AGND to

SYSFB

program the system output voltage. Leave the pin float to disable the function.

13

14

SYS DC-DC regulator output to power the system load and charge the battery.

BATT Positive battery terminal.

Charge current program pin. A resistor from the pin to AGND can program the charge

current during CC charge. Float the pin will disable the charge function.

15

16

17

ISET

Thermistor input. Connect a resistor from this pin to VCC and the thermistor from this pin to

ground. The thermistor is usually inside the battery pack.

NTC

Input current limit program pin. A resistor from the pin to AGND can program the input

current limit with adapter input.

ILIM

18

19

20

TMR Set timer out period. Connect TMR pin to AGND to disable the internal timer.

VLIM Input voltage clamp program pin.

VCC Supply voltage of the IC.

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

ABSOLUTE MAXIMUM RATINGS ⁽¹⁾

IN, SW ........................................ -0.3V to +20V

BATT, SYS .................................... -0.3V to +6V

BST ............................................. -0.3V to +26V

All Other Pins................................. -0.3V to +6V

Thermal Resistance ⁽⁴⁾

QFN-20 (3mmx4mm) ............. 48...... 11... C/W

θ_JAθ_JC

Notes:

1) Exceeding these ratings may damage the device.

2) The maximum allowable power dissipation is a function of the

maximum junction temperature T_J(MAX), the junction-to-

ambient thermal resistance θ_JA, and the ambient temperature

T_A. The maximum allowable continuous power dissipation at

any ambient temperature is calculated by P_D(MAX) = (T_J

(MAX)-T_A)/θ_JA. Exceeding the maximum allowable power

dissipation will cause excessive die temperature, and the

regulator will go into thermal shutdown. Internal thermal

shutdown circuitry protects the device from permanent

damage.

(2)

Continuous Power Dissipation (T_A= +25°C)

QFN20 3mmx4mm ....................................2.6W

Junction Temperature..............................150C

Lead Temperature ...................................260C

Storage Temperature.................–65°C to 150°C

Recommended Operating Conditions ⁽³⁾

Supply Voltage V_IN.......................... 4.0V to 10V

Operating Junction Temp. (T_J)....-40°C to +125°C

3) The device is not guaranteed to function outside of its

operating conditions.

4) Measured on JESD51-7, 4-layer PCB.

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

ELECTRICAL CHARACTERISTICS

V_IN= 5.0V, T_A= 25C, unless otherwise noted.

Parameters

Symbol Condition

Min

Typ

Max Units

Input Power (IN)

IN Operating Range

V_IN

4.0

3.65

3.35

240

40

10

V

Rising

Falling

Rising

Falling

3.8

3.5

280

70

3.95

3.65

320

120

IN Under Voltage Lockout

Threshold

V

mV

IN vs. BATT Threshold

Rising

V_BST-V_SW

2.55

2.9

150

1.6

3.25

V

BST Voltage Threshold

Switching Frequency

Hysteresis

mV

MHz

1.4

1.8

USB2.0 Mode

400

750

450

825

500

900

mA

USB3.0 Mode

Default Mode

1840 2000 2160 mA

Programmable Mode, R_ILIM=23k

(MP2617B)

1840 2000 2160 mA

Input Current Limit

I_IN

Programmable Mode, RILIM=22.47k

(MP2617A)

1840 2000 2160 mA

Programmable Mode,

RILIM=48k (MP2617A)

900

1.1

950

1000 mA

Input Current Limit Reference

Voltage

V_ILIM

1.14

1.18

V

High-side NMOS On Resistance R_{H_DS(ON)}Include the BLOCK FET

Low-side NMOS On Resistance R_L__DS(ON)

120

80

130

100

mΩ

High-side NMOS Peak Current

limit

3.8

4.8

5.8

A

Input Voltage Clamp Threshold

V_VLIM

Voltage on VLIM

1.49

1.52

2.4

2.8

3.8

1.55

V

Charger Enabled, USB2.0 Mode

Charger Enabled, USB3.0 Mode

Charger Enable, Programmable Mode

5

mA

Input Quiescent Current

I_IN

Charger Enabled, Default Mode

Disabled, EN=0V

3.8

3

5

mA

uA

SYS to IN reverse current

blocking

SYS=SW=4.5V,VIN=0V, monitor VIN

leakage

0.01

0.2

uA

SYS Output (MP2617A)

Minimum

Voltage

SYS

Regulation

SYS voltage @ V_BATT≤3.4V, SYSFB

float

V_SYS

3.45

3.6

3.75

V

3.4V<V_BATT≤4.2V, SYSFB float

BATT Float

V_BATT

0.2V

+

3.5

4.63

SYS Regulation Voltage

SYS Reference Voltage

V_SYS

User Programmed by SYSFB

4.22

V

V_{SYS_REF}

1.135 1.152 1.170

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

ELECTRICAL CHARACTERISTICS (continued)

V_IN= 5.0V, T_A= 25C, unless otherwise noted.

Parameters

Symbol Condition

Min

Typ

Max Units

SYS Output (MP2617B)

SYS voltage @ V_BATT≤3.4V,

SYSFB float

Minimum SYS Regulation Voltage

SYS Regulation Voltage

V_SYS

3.45

3.6

3.75

V

3.4V<V_BATT≤4.2V, SYSFB float

BATT Float

V_BATT

0.2V

+

3.5

4.5

4.4

V_SYS

User Programmed by SYSFB

4.08

V

SYS Reference Voltage

Battery Discharge

V_{SYS_REF}

1.135 1.152 1.170

BATT to SYS Resistance

V_IN=0V, I_SYS=200mA, V_BATT=4.2V

V_SYS>V_BATT–800mV, V_BATT=4.2V

SYS short

40

5

50

6

mΩ

A

4

BATT to SYS Current Limit

230

mA

Battery Charger Voltage Spec (MP2617A)

V_BATT>V_RECH, I_CHG≤I_BF,SYSFB float 4.328 4.35 4.372

V

V_SYS

-

Terminal Battery Voltage

V_BATT

V_SYS<4.2V Programmed by

SYSFB Pin

0.04 x

I_BF

SYSFB Float

4.04

3.99

4.14

4.09

85

4.24

4.19

V

Recharge Threshold at V_BATT

V_RECH

SYSFB programmed

Recharge Hysteresis

mV

V

Trickle Charge Threshold

Trickle Charger Hysteresis

3.01

3.11

200

3.21

mV

Battery Charger Voltage Spec (MP2617B)

V_BATT>V_RECH, I_CHG≤I_BF,SYSFB float 4.179

4.2

4.221

V

V_SYS

0.04 x

I_BF

-

Terminal Battery Voltage

V_BATT

V_SYS<4.2V Programmed by

SYSFB Pin

SYSFB Float

3.9

4.0

3.95

85

4.1

V

Recharge Threshold at V_BATT

V_RECH

SYSFB programmed

3.85

4.05

Recharge Hysteresis

mV

V

Trickle Charge Threshold

Trickle Charger Hysteresis

Battery Charger Current Spec

Trickle Charge Current

2.9

5%

3

3.1

200

mV

I_TRICKLE

I_BF

10%

I_CC

Termination Charger Current

15%

200

I_BFMaximum Limit

150

mA

3.02

5

R_ISET=760

2.475 2.75

1.26 1.4

A

Constant Current Mode Charge

Current

I_CC

R_ISET=1.53k

R_ISET=4.6k

1.54

A

0.405 0.450 0.495

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

ELECTRICAL CHARACTERISTICS (continued)

V_IN= 5.0V, T_A= 25C, unless otherwise noted.

Parameters

Symbol Condition

Min

Typ

Max

Units

ISET Reference Voltage

1.1

2.4

2.2

1.15

2.6

1.2

2.8

2.6

V

Rising

Falling

Battery UVLO

2.4

V_BATT

65mV

-

Idea Diode Regulation Voltage

BATT Leakage Current

V_SYS

I_BATT

Supplement Mode

mV

µA

V_BATT=4.2V, SYS float,

V_IN=PGND

20

30

__________ _____________

ACOK, CHGOK

__________ _____________

ACOK, CHGOK Pin Output

Low Voltage

__________ _____________

Sinking 5mA

270

0.1

350

0.5

mV

ACOK,CHGOKPin Leakage

Current

Connected to 3.3V

μA

Timer

Trickle Charge Time

Total Charge Time

C_TMR=0.1µF, I_CHG=1A

45

Min

6.5

Hour

Negative Temperature Coefficient (NTC) Control

NTC Low Temp Rising

Threshold

V_THL

R_NTC=NCP18XH103F 0°C

63

32

65

35

67

35

%V_CC

mV

Hysteresis on Low Temp

Threshold

NTC High Temp Falling

Threshold

V_THH

R_NTC=NCP18XH103F, 50°C

33.5

70

%V_CC

mV

Hysteresis on High Temp

Threshold

VCC Supply

Rising

3.15

2.8

3.35

3

3.55

3.2

V

VCC UVLO

Falling

VCC Output Voltage

0mA<I_VCC<25mA, V_IN=6V

4.3

4.5

40

4.6

V

VCC Output Current Limit

mA

Logic

0.4

8

V

ENInput Low Voltage

ENInput High Voltage

1.5

4

EN=4V

μA

ENInput Current

M0, M1

-0.5

1.5

-0.1

EN=0V

Logic High

Logic Low

V

0.4

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

ELECTRICAL CHARACTERISTICS (continued)

VIN = 5.0V, TA = 25C, unless otherwise noted.

Parameters

Symbol Condition

Min

Typ

Max

Units

Protection

Thermal Limit Temperature

Thermal Shutdown

120

150

°C

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

TYPICAL PERFORMANCE CHARACTERISTICS

V_IN= 5.0V, V_BATT= Full Range, Default Mode, I_INLimit=2A, V_SYS=4.4V, R6 and R7 are float, I_CHG=2A,

V_INClamp=4.5V, L = 1.2 µH, T_A= +25ºC, Test in MP2617B, unless otherwise noted.

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

TYPICAL PERFORMANCE CHARACTERISTICS (continued)

V_IN= 5.0V, V_BATT= Full Range, Default Mode, I_INLimit=2A, V_SYS=4.4V, R6 and R7 are float, I_CHG=2A,

V_INClamp=4.5V, L = 1.2 µH, T_A= +25ºC, Test in MP2617B, unless otherwise noted.

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

TYPICAL PERFORMANCE CHARACTERISTICS (continued)

V_IN= 5.0V, V_BATT= Full Range, Default Mode, I_INLimit=2A, V_SYS=4.4V, R6 and R7 are float, I_CHG=2A,

L = 1.2 µH, T_A= +25ºC, Test in MP2617B, unless otherwise noted.

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

TYPICAL PERFORMANCE CHARACTERISTICS (continued)

V_IN= 5.0V, V_BATT= Full Range, Default Mode, I_INLimit=2A, V_SYS=4.4V, R6 and R7 are float, I_CHG=2A,

L = 1.2 µH, T_A= +25ºC, Test in MP2617B, unless otherwise noted.

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

TYPICAL PERFORMANCE CHARACTERISTICS (continued)

V_IN= 5.0V, V_BATT= Full Range, Default Mode, I_INLimit=2A, V_SYS=4.4V, R6 and R7 are float, I_CHG=2A,

L = 1.2 µH, T_A= +25ºC, Test in MP2617B, unless otherwise noted.

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

OPERATION

BST

IN

HSG

SYSFB1

EAO

EA

3.6V

L

Converter

control

Max(A,B)

SW

SYS

VBATT+200mV

Driver

1

0

M

Input current

limit reference

selector

C

LSG

Iref

M

EAO

SYSFB

VBG

VREF

SYSFB

SYS

SYSFB

EA

ILIM

SYSFB1

VLIM

1.5V

mO

4 0

V_BATx 2

Charge

Pump

VIN

Ideal diode

regulation

VTH

SYS

Battery switch

current limit

BATT

EN

3.5 V coarse

LDO &

EN

3.0 V UVLO

CC/ CV linear

charger

BATTFB

VBG

VREF_CC

VCC

Bandgap

& Bias

VBG

EN

4.5 V LDO

Charger Control & Chip Logic

UVLO

.

V UVLO

3 8

VIN

ISET

CHGOK

ACOK

TMR

NTC

GND

Figure 1—Function Block Diagram

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

the combination of the system load and battery

charger. The regulator contains input current

Introduction

The MP2617A and MP2617B is a switching

charger IC, with integrated smart power path

management for powering the system and

charging a single cell battery simultaneously and

independently.

measurement and control scheme to ensure the

average input current remains below the level

programmed via ILIM pin or logic inputs M0&M1.

This meets the adapter capacity limit or stays in

compliance with USB specification.

The MP2617A and MP2617B includes input DC-

DC step down converter for wide range of DC

sources and USB inputs. It has precision average

input current limit to make maximum use of the

allowable input power. This feature allows fast

charging when powering from an USB port, and

ensures the input current never exceeds the

input power specification especially when the

input power comes from a USB port. Additionally,

the input current limit threshold can be

programmed by logic inputs or a resistor to

ground from the ILIM pin.

When the input voltage is higher than UVLO and

280mV higher than the battery voltage, input

——————

voltage OK signal is active (ACOK turns low) and

the DC-DC converter soft-starts. If the input

power is sufficient to supply the combination of

the system load and battery charger, and the

input current limit loop is not triggered. The

converter output voltage V_SYSwill be regulated:

1) If BATT>3.4V, V_SYSis approximately 0.2V

above the battery voltage to minimize the power

loss of the battery charger during fast charging.

The MP2617A and MP2617B implements an on-

chip 40mΩ MOSFET which works as a full-

featured linear charger with trickle charge, high

accuracy constant current and constant voltage

charge, charge termination, auto recharge, NTC

monitor, built-in timer control, charge status

indication, and thermal protection. The charge

current can be programmed by an external

resistor connected from the ISET pin to AGND.

The IC limits the charge current when the die

temperature exceeds 120°C.

2) If BATT<3.4V, V_SYSis fixed at 3.6V to power

the system immediately even when a drained

battery is inserted to be charged. Figure 2 shows

the relationship of V_SYSvs. V_BATT.

System voltage can also be regulated to any

value between 4.08V to 4.4V in MP2617B (4.22V

to 4.63V in MP2617A) by using a resistor divider

on the SYSFB pin. This is shown as R6 and R7

in Figure 10. If the SYSFB is left floating, the

system program is invalid, and V_SYSis regulated

as Figure 2.

The 40mΩ MOSFET works as an ideal diode to

connecting the battery to the system load when

the input power is not enough to power the

system load. When the input is removed, the

40mΩ MOSFET is turned on allowing the battery

to power up the system.

The converter adopts fixed off-time control to

extend the duty cycle (close to 100%) when the

input of the converter is close to V_SYS.

4.4V

4.2V

With smart power path management, the system

load is satisfied in priority then the remaining

current is used to charge the battery. The

MP2617A and MP2617B will reduce charging

current or even use power from the battery to

satisfy the system load when its demand is over

the input power capacity.

V_SYS

200mV

3.6V

V_BATT

Figure 1 shows the function block diagram of the

MP2617A and MP2617B.

DC-DC Step Down Converter

3.4V

4.2V

The DC-DC converter is a 1.6MHz step-down

switching regulator to provide the input power to

Figure 2 — MP 2617B SYS Regulation

Output

the

SYS,

which

drives

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

Close to 100% duty operation, BST refresh

to control the operation duty. In this mode, the

input voltage will be clamped according to the

value set by the resistor divider. The control to

the system voltage and charge current is the

same as the one explained in the input current

limit. Charge current drops down to satisfy the

system current request first. This feature

provides a second protection to the input power

and ensures the safe operation of the input

adapter. Even if a wrong adapter is inserted, the

MP2617A and MP2617B can continue operation,

providing the maximum power to its load. User

can program the input voltage limit value through

the resistor divider from IN to VLIM to AGND.

operation makes sure the driver voltage of the

HS will be charged by turning on the LS until

negative IL hit a threshold. If the input power is

insufficient to supply the combination of the

system load and battery charger, the DC-DC

converter will limit the total power requirement by

restricting the input voltage, input current and the

peak current through the MOSFET. The power

path management will reduce the charge current

to satisfy the external system load in priority.

According to this feature, the USB specification is

always satisfied first. Even if the charge current is

set larger than the USB input current limit, the

real charge current will be reduced as needed.

Peak Current Limit: The peak current of the high

side switch of the DC-DC converter is sensed

during every cycle, it is compared to the

reference 4.8A. If the peak current hits the

threshold, the peak current limit mode is

triggered. The control of the charge current is the

same with the above two limits.

Input Limit State

If the input power is insufficient to supply the

combination of the system load and battery

charger,

the

MP2617A

and

MP2617B

implements three input limit control loops to

reduce the charge current and satisfy the

external system load in priority. The input in this

case might be limited as follows: input current

limit, input voltage limit and DC-DC peak current

limit.

Input Current Limit Setting

The current at ILIM is a precise fraction of the

adapter input current. When a programming

resistor is connected from ILIM to AGND, the

voltage on ILIM represents the average input

current of the PWM converter. And the input

current approaches the programmed limit, ILIM

voltage reaches 1.14V.

Input Current Limit: When the input current is

higher than the programmed input current limit

the input current limit loop takes the control of the

converter and regulates the input current at

constant value. When the battery voltage is over

3.4V, the output voltage (V_SYS) will drop down

according to the increase of the system current,

and the charge current drops down after the

BATT-to-SYS switch (40mΩ MOSFET) is fully on

according to V_SYSdropping down. During this

process, the system voltage is slightly higher

than V_BATT. When the battery voltage is lower

than 3.4V, to maintain the minimum system

voltage and ensure the system operation, the

input current limit control will pull down the

charge current directly to reduce the load of the

converter so that the system current is satisfied

in priority.

The average input current limit can be set

through the resistor connecting from ILIM to

AGND according to the following expression:

40000

I_{IN_LIM}=1.14

(mA)

R_ILIM(kΩ)

When USB input, the input current limit is set

internally and the programmed value is invalid.

The MP2617A and MP2617B provides typical of

450mA input current limit for USB2.0

specification and a typical of 825mA for USB3.0

specification respectively.

Input Voltage Limit: A resistor divider from IN pin

to VLIM pin to AGND is used for the input voltage

limit control. When the voltage on VLIM pin hits

the reference voltage of 1.52V, the output of the

input voltage limit error amplifier will drop in

The user can choose to set the input current limit

through the two logic pins M0 and M1 as shown

in Table 2 according to its input specification.

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

When both M0 and M1 pins are float, they are

pulled to the logic high, under this condition, the

input current is limited to a default value of 2A.

satisfied first over the battery charge current. If

the system load requirement is low, the battery

can be charged at full constant current.

Table 2―Input Current Limit Setting

When the battery voltage reaches the battery full

threshold, the charger enters the “constant

voltage mode” operation.

M0

Low

M1

Low

High

Mode

USB2.0 Mode

USB3.0 Mode

End of Charge (EOC) and Indication

High

Low

Programmable Mode

In constant voltage charge mode, the battery

voltage is regulated at 4.2V (MP2617B) and

4.35V (MP2617A) (when SYSFB is float or SYS

is programmed higher than battery full threshold)

and the charge current decreases naturally.

Once the charge current hits the battery full

threshold I_BF(1/10 programmed charge current),

the battery is fully charged and charge cycle is

terminated.

High/Float High/Float Default Mode

Input Voltage Limit Setting

The input voltage can be limited at a value set by

a resistor divider from IN pin to VLIM pin to

AGND according to the following expression

(Typical Application Circuit):

R1+R2

V_{IN_LIM}=1.52

(V)

If the charge current drops below I_BFbecause of

any limit condition, the MP2617A and MP2617B

will come out of CV mode, and the charge full

detection is invalid.

R2

When the voltage on VLIM pin drops and hits the

reference voltage 1.52V, the input voltage will be

clamped to the setting value.

A safe timer starts at the beginning of each new

charge cycle and it monitors if the whole charge

period is within the programmed time limit. After

each charge cycle, when the battery is indicated

as full, the timer counter will be reset. If the time

is expired while the charging is still on going, the

Battery Charger

The MP2617A and MP2617B completes charge

operation consist of trickle charge, automatic

charge termination, charge status indication,

timer control, NTC indication, automatic recharge,

and thermal limiting.

timer will force the MP2617A and MP2617B to

_____________

terminate charging CHGOK is blinking to indicate

the fault condition.

When the PWM converter is out of soft start, the

battery charge cycle begins, the MP2617A and

MP2617B first determines if the battery is deeply

discharged. If the battery voltage is lower than

the trick charge threshold (typical 3.0V), the

battery charger starts in “trickle charge mode”.

The trickle charge current is limited to 10% of the

programmed charge current until the battery

voltage reaches 3.0V. If the charge stays in the

“trickle charging mode” for longer than ”trickle

If system voltage is programmed lower than 4.2V

(MP2617B) and 4.35V (MP2617A) by the resistor

divider at the SYSFB pin, the battery will be

charged most close to V_SYSuntil the charge

current reaches the I_BFthreshold.

Automatic Recharge

Once the battery charge cycle is completed, the

MP2617A and MP2617B turns off indicating the

battery full status. During this process, the

battery power may be consumed by the system

load or self discharge. If the input power is

always on, to ensure the battery not to be

exhausted, the new charge cycle will

automatically begin when the battery voltage falls

below the auto-recharge threshold V_RCHGwhen

the SYSFB is float, and 50mV lower if the SYSFB

is connected to a resistor divider. The timer will

re-start when the auto-recharge cycle begins.

charge timer period”, the “timer out” condition is

_____________

triggered, the charge is terminated and CHGOK

will start blinking to indicate that the battery is

unresponsive. When the battery voltage is above

3.0V, the charger is operating at “constant

current mode.” The current delivered to the

battery will try to reach the value programmed by

the ISET pin. Depending on the available input

power and system load conditions, the battery

charger may or may not be able to charge at the

full programmed rate. The system load is always

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

During the charge off state when the battery is

V_BATT-40mV

Enable Ideal Diode Mode

Disable Ideal Diode Mode

fully charged, if the input power is recycled, or

the EN signal is refreshed, the charge cycle will

re-start and the timer will refresh even if the

battery voltage is above the auto-recharge

threshold.

V_SYS

V_BATT+40mV

Charge Current Setting

The charge current of the MP2617A and

MP2617B is programmed using a single resistor

from ISET pin to ground. The program resistor

and charge current are calculated using the

following equations:

Figure 3— Ideal Diode Mode Enable/Disable

Logic Control

The MP2617A and MP2617B have two separate

enable control pins.

_____

1800

I_CHG 1.15

(mA)

EN is a logic control pin that controls the

R_SET(k)

_____

operation of the whole IC. When EN is low, the

At either constant current mode or constant

voltage mode, the voltage at the ISET pin is

proportional to the actual charge current

delivered to the battery, I_BATT. The charge current

can be calculated by monitoring the ISET pin

voltage with the following formula:

IC is enabled and the PWM converter output

_____

powers the system and the charger. When EN is

high, both the PWM converter and the charger

are disabled. The BATT to SYS switch turns fully

on to connect the battery to power the system.

The ISET pin can be also used to control the

operation of the charger. Setting ISET pin floating

will disable the charger function while the output

of PWM converter will continue supply power to

system. On the other hand, a resistor from ISET

to AGND will enable the charging at the

programmed charge current.

V

I_BATT

=

^ISET×I_CHG

1.15

Additionally, the actual battery charge current

may be lower than the programmed current due

to limited input power available and prioritization

of the system load.

The logic control of the ISET pin of the MP2617A

and MP2617B can be realized as Figure 4. In this

way, the user can choose logic low to be “off”

signal or logic high to be ”on” signal with a N-

MOSFET.

Battery charge full current threshold I_BFis set

internally at 10% of the programmed charge

current. However, I_BFhas a 150mA maximum

limit which can not be exceeded.

Ideal Diode Mode

If the system current requirement increases over

the preset limit of the PWM converter, the

additional current will be drawn from the battery

via the BATT-to-SYS switch. To avoid very large

currents being drawn from the battery which

might affect the reliability of the device, the

MP2625B controls the charge switch to work at

ISET

OFF ON

R_ISET

Figure 4— ISET Logic Control

__________

the ideal diode mode regulating V_SYSto V_BATT

-

Input Power Status Indication (ACOK)

65mV when V_SYSis 40mV lower than V_BATTis

detected. Only when V_SYSis 40mV higher than

V_BATT, the charger switch exits the ideal diode

mode, and the charge cycle softly restarts.

An internal under voltage lockout circuit monitors

the input voltage and keeps the IC in off state

until the input rises over the rising threshold

(3.8V). When the input voltage decreases below

threshold (3.5V), the IC will turn off, and the

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

Table 2―Charger Status Indication

system load will be powered by the battery

__________

Charger Status

ACOK

low

CHGOK

automatically. ACOK is an open-drain, active-low

In charging, supplement

mode

End of charge, ISET

disable charger only.

output that indicates the status of input power.

The input is considered valid when the input

voltage is over the UVLO rising threshold, and

310mV higher than the battery voltage to ensure

both the converter and the charger can operate

low

high

blinking at

6Hz

NTC fault, timer out

normally. If the input voltage from an adapter or

__________

V_INabsent, EN disable,

thermal shutdown

high

from a USB port is indicated OK, ACOK will turn

low.

_____

Timer Setting

During EN off or thermal shutdown conditions,

__________

The MP2617A and MP2617B uses an internal

timer to terminate charge if the timer times out.

The timer duration is programmed by an external

capacitor at the TMR pin and related to the real

charge current.

the ACOK turns high to indicate no power is

__________

provided by the input to the system. The ACOK

signal indicates if input supplies power to the

system load or not. Any other condition can not

__________

affect the ACOK indication as long as the input

power is present.

The trickle mode charge time is:

C_TMR

t_{Trickle _ TMR} 45

(min) (I_CHG1A)

_____________

0.1μF

Charge Status Indication (CHGOK)

_____________

The total charge time is:

CHGOK is an open-drain, active-low output that

_____________

indicates the status of charge. CHGOK will be

low during normal charging operation, turn high

after charge full, and blink if a fault condition

happens including NTC fault (battery temperature

invalid) and timer out (bad battery).

C_TMR

t_{Total_TMR} 6.5

0.1μF

(hr) (I_CHG1A)

The above equations are based on 1A charge

current. As a result of power path management

control, charge current might vary during normal

operation, under this condition, the MP2617A

and MP2617B automatically takes into account

this variation and adjust the timer period

accordingly.

_____________

In the event of a fault condition, CHGOK

switches at 6Hz with the 50% duty cycle and

enter “blinking” mode. The user should check the

application circuit to find out the root cause of the

fault condition if the “blinking” signal is asserted.

_____________

When the charge current is set larger than 1A,

the safe timer period is reduced accordingly with

the same TMR capacitor. If the charge current is

reduced because of insufficient input power, the

timer period is increased proportionally by the

same rate at which the charge current is reduced.

If charge is stopped due to high system load, the

timer is temporarily suspended.

For no battery condition, CHGOK is blinking

according to the transition between charging and

charge full. The blinking frequency is determined

by the cycle of charge and discharge of the

output capacitor.

When the charge current to the battery is low or

in the event the battery is in supplement mode

_____________

caused by the insufficient input power, CHGOK

keeps low to avoid providing false charge full

indication.

This feature avoids indicating a false trigger

indication for bad battery indication when there is

little charge current delivered to the battery as a

result of the insufficient input power. When the

timer out condition occurs, the MP2617A and

__________

_____________

Table 2 shows the ACOK and CHGOK status

under different charge conditions.

MP2617B terminates the charge at once and

_____________

CHGOK blinks to indicate the fault status. If one

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

150^oC as the IC enters thermal shutdown

protection.

of the following events happens, the timer is

refreshed and the MP2617A and MP2617B re-

starts the charge cycle.

Battery Discharge Protection

When the input power is removed or invalid, the

system load will draw power from the battery via

the battery switch. Under this condition, the

battery switch is fully on to minimize the power

loss. The MP2617A and MP2617B integrates

battery discharge protection. If the battery

discharge current is larger than the discharge

current limit threshold I_DIS(5A), the current will be

regulated at the preset limited value. And if the

current increases further, the SYS voltage starts

to decrease. When V_SYSdrops to about 800mV

lower than V_BATT, SYS short condition is detected.

Under this condition, the discharge current is

limited at 230mA. In the event of a short from

system to GND the discharge current from the

battery to the system is also limited to 230mA.

Furthermore, battery voltage UVLO is always

monitored. If the battery voltage is lower than the

battery UVLO threshold, the battery switch is

turned off immediately. This feature makes sure

the battery from over-discharged.



Input re-startup

_____



Refresh EN /ISET signal

Auto-Recharge

NTC Thermistor

The NTC pin allows MP2617A and MP2617B to

sense the battery temperature using the Negative

Thermal Coefficient (NTC) thermistor usually

available in the battery pack to ensure safe

operating environment of the battery. A resistor

with appropriate value should be connected from

VCC to NTC and the NTC resistor is from NTC

pin to AGND. The voltage on NTC pin is

determined by the resistor divider whose divide

ratio as the different resistance of the NTC

thermistor depends on the ambient temperature

of the battery.

The MP2617A and MP2617B has an internal

NTC voltage comparator to set the upper and

lower limit of the divide ratio. If NTC pin voltage

falls out of this range it means the temperature is

outside the safe operating range,

Dynamic Power Path Management (DPPM)

In the presence of a valid input source, the PWM

converter will supply the current to both the

system and the battery charger.

As a result, the MP2617A and MP2617B will stop

charging and report it on indication pins.

Charging will automatically resume after the

temperature falls back into the safe range.

The voltage V_SYSis regulated based on the value

of the battery voltage. When V_BATTis higher than

3.4V, V_SYSis regulated 200mv above V_BATTto

charge the battery. When V_BATTis lower than

3.4V, to ensure the system can still be powered

up even with a drained battery connected, V_SYSis

regulated at constant 3.6V.

Thermal Protection

The MP2617A and MP2617B implements

thermal protection to prevent the thermal damage

to the IC or surrounding components. An internal

thermal sense and feedback loop will

automatically decrease the charge current when

the die-temperature rises to about 120^oC. This

function is referred as charge current thermal

fold-back. This feature protects the MP2617A

and MP2617B from excessive temperature due

to high power operation or high ambient thermal

conditions. Another benefit of this feature is

charge current can be set according to the

requirement rather than worst-case conditions for

a given application with the assurance of safe

operation. The MP2617A and MP2617B will stop

charging if the junction temperature rises above

When the input source is overloaded, either the

current exceeds the input current limit or the

voltage falls below the input voltage limit, the

MP2617A and MP2617B then reduces the

charge current until the input current falls below

the input current limit and the input voltage rises

above the input voltage limit. If the system

current increases beyond the power allowed by

the input source, additional power will be drawn

from the battery via an on-chip 40mΩ MOSFET

working as an ideal diode.

Additionally, if the input source is removed, the

MP2617A and MP2617B will turn on the 40mΩ

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

Taking the MP2617B for example, Figure 5

shows the operation flow chart of the MP2617B

while Figure 6 shows the operation process.

MOSFET allowing the battery to power the

system load to keep the operation of the portable

device.

Operation Flow Chart

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

Yes

Clamp DC-DC

EAOto regulate

the part

Any Limit condition

triggered?

at the limit state

No

V_BATT<3.4V?

V_BATT>3.0V?

Yes

No

Yes

No

Trickle Charge

I_CHG=10%I_CC

V_SYSdrops down,

Charge switch

is fully on

Decrease I_CHG

Keep V_SYS=3.6V

,

CC/CV Charge

Yes

No

Satisfy System current

Charge the battery with

remaining current

No

Limit condition

Removed?

I_CHG=I_BF

?

No

Yes

Disable

Ideal Diode Mode

Charge in

CV mode and

I_CHG<I_BF?

No

Charge Full, EOC=1

TMR off,

Yes

I_CHG=0?

Yes

clear the counter

DC-DC keeps work

Yes

No

V_SYS>V_BATT+40mV?

V_SYS<V_BATT-40mV?

Yes

V_SYS<V_BATT-40mV?

No

Yes

V_BATT>V_{BATT_UVLO}

?

No

Yes

V_BATT<V_RCHG

?

Ideal Diode Mode:

V_SYS=V_BATT-65mV,

Enable discharge

current limit

Battery switch shuts down,

DC-DC in over load

condition,

V_SYSdrops down

Figure 5— MP2617B Operation Flow Chart under No Fault Condition

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

Normal

operation

voltage

UVLO

Threshold-Hys

UVLO

Thresohold

V_IN

0

Power Path Management

Battery

Supplement

Mode

I_SYS

0

CV Charge

CC Charge

Trickle Charge

Battery

Full

I_BATT

0

I_SYS-I_{IN_LIM}

Input Power

Current Limit

I_{IN_LIM}

I_{IN_AVE}

0

Supplement

Mode-

Discharging

Auto-

Recharging

Self-

discharging

Power off-

discharging

Charging

V

_BATT=4.0V

V_SYS

V_BATT

V_BATT=3.4V

V

_BATT=3.0V

0

Figure 6— MP2617B Operation Process under No Fault Condition

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

For example, if the typical I_CHGis designed as

APPLICATION INFORMATION

COMPONENT SELECTION

Setting the Input Current Limit

2A, then the R_SETis calculated at 1.05kΩ. The

tolerance of the I_CHGsetting is ±10%. If the

minimum or maximum charge current is

required, first the typical value should be

calculated according to the tolerance. After that,

calculate the resistor according to formula (2).

1% accuracy resistor is used for this setting.

First the input current limit can be set by the M0

and M1 pins refer to the Table 1, the exact

current value in minimum, typical and maximum

is listed in the EC table.

For a given setting resistor, the charge current

can be calculated by the same way did in the

input current limit setting. Usually in USB mode,

the charge current is always set over the USB

input limit specification. Then the MP2625

regulates the input current constant at the

limitation value. Thus the real CC charge

current is not the setting value, it varies with

different input and battery voltages.

Under program mode, connect a resistor from

the ILIM pin to AGND to program the input

current limit for different input ports. The

relationship between the input current limit and

setting resistor is as Equation (1) which is

shown in following again:

40000

(1)

I_{IN_LIM}=1.14

(mA)

R_ILIM(kΩ)

For MP2617A/B, IILIM is not over 3A.

The tolerance is ±8% of the input current limit

setting.

The maximum CC charge value can be

calculated as:

V I_ILIM

IN

I_{CC _ MAX}



(A)

(3)

So for a required minimum input current limit

value, just calculate its typical value first, then

calculate the setting resistor based on Equation

(1). Also the maximum value can be calculated

V_TC

Where VTC is trickle charge threshold (3V) and η

is the current charge efficiency. Assume

VIN=5.5V, IILIM=1A, suppose η=83%, thus

ICC_MAX=1.52A.

Figure 7 shows a calculating charge current

curve by limiting the input current limit.

according to the tolerance.

1% accuracy

resistor is used for this setting. Also, for a given

resistor of R_ILIM, the input current limit can be

calculated. Following table is an example:

Table 3: Example of R_ILIMsetting

I

l

i

m

=

1

.

4

2A

1A

4

R_ILIM

(kΩ)

54.9

I_{IN_LIM}

(mA)

A

Resistor

8%

-8%

I

l

i

m

=

1

A

Typ.

Min.

Max.

830.601 897.049 764.153

I

l

i

m

54.351 838.991 906.11 771.872

55.449 822.377 888.168 756.587

=

0

.

8

2

5

A

Therefore, if customer selected a 54.9k in 1%

accuracy resistor for the input current limit

setting, then the typical input current limit value

is 830.6mA, the minimum is 756.6mA and the

maximum is 906mA.

3V

4.2V

Battery Voltage

Figure 3—I_CHGVariation with Different Input

Current Limit

Setting the Charge Current

Setting the Input Voltage Limit

R_ISETconnecting from the ISET pin to AGND

sets the charge current (ICHG). The relationship

between the charge current and setting resistor

is as Equation (2) which is shown in following

again:

The input clamp voltage is set using a resistive

voltage divider from the input voltage to VLIM

pin. The voltage divider divides the input

voltage down to the limit voltage by the ratio:

R2

1800

(4)

(2)

V_VLIM= V

×

(V)

I_CHG 1.15

(mA)

IN_LIM

R1+R2

R_SET(k)

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

Thus the input voltage is:

Selecting the Inductor

Inductor selection trades off among cost, size,

and efficiency. A lower inductance value

corresponds to a smaller size, but results in

higher ripple currents, higher magnetic

R1+R2

R2

V

_{IN_LIM}= V_VLIM

×

(V)

(5)

The voltage clamp reference voltage V_VLIMis

1.52V, and a typical value for R2 can be 10kΩ.

With this value, R1 can be determined by:

hysteretic

losses,

and

higher

output

capacitances. From a practical standpoint, the

inductor ripple current does not exceed 30% of

the maximum load current under worst cases

conditions. For example, if the I_CHGis setting to

3A in MP2617B, then, ΔI_Lis general set at 0.9A.

V

_{IN_LIM}- V

R1=R2×

^VLIM(V)

(6)

V_VLIM

For example, for a 4.65V input limit voltage, R2

is 10kΩ, and R1 is 20.6kΩ.

However, for the light load condition, the

inductor ripple current will be very small which

may cause unstable operation due to the peak

current mode control of the IC. For stable

operation, the experienced minimum limit value

for inductor current ripple is 0.5A. Therefore, the

inductor current ripple is the maximum one of

30% times I_CHGand 0.5A.

The minimum value and the maximum value of

the input voltage limit can be calculated

according to the accuracy of the resistor and

the tolerance of V_VLIM. 1% accuracy resistors

are used for R1 and R2.

Setting the System Voltage

The system voltage can be regulated to any

value between 4.08V to 4.4V (MP2617B) by the

resistor divider on SYSFB pin as R6 and R7 in

Figure 10.

And the inductance can be calculated according

to Equation (9):

R6 R7

V_SYS V_{SYS_REF}



(7)

V V_SYS

I_{L _MAX}V f_S(MHz)

The peak current of the inductor is calculated

as Equation (10):

V_SYS

IN

R7

L 

(H)

(9)

Where V_{SYS_REF}is 1.152V, the reference voltage

of SYS. With a typical value for R7, 10kΩ, R6

can be determined by:

IN

V_SYS V

%ripple

R6  R7

^SYS_REF(V)

(8)

I_PEAK I_LOAD(MAX)(1

)

(mA)

(10)

2

V_{SYS_REF}

Where VIN, VSYS, and fS are the typical input

voltage, the output voltage, and the switching

frequency, respectively.

For example, for a 4.2V system voltage, R7 is

10kΩ, and R6 is 26.5kΩ. 1% resistors are

selected for the R5 and R6.

Following Table 4 provides the selection guide

of the inductance based on different input

voltage.

Be noted that, the minimum V_SYSis limited to be

higher than the maximum value of the auto-

recharge threshold which is 4.05V.

Table 4: Inductance Selection Guide under different Input Voltage

Inductance Selection

SPEC

V_IN

L_MIN

(μH)

L_MAX

L

Saturation

DCR

V V_SYS

V_SYS

IN

Package

(μH) (μH) Current (A)⁽⁵⁾(mΩ)

L 

I_L

V f_S(MHz)

IN

Application

Required

5V

9V

0.367 1.25

1.0

2.2

>3.95

<50

ΔI_L=max (0.3*I_CHG,0.5A)

ΔI_LMIN=0.5A

Application

Required

1.5 2.8

ΔI_LMAX=0.9A

NOTE:

5) Saturation Current of the inductor should be higher than the IPEAK, add 0.5A margin here.

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

Selecting the Input Capacitor

the system load to ensure it properly absorbs

the ripple current.

The input capacitor C1 from the typical

application circuit absorbs the maximum ripple

current from the PWM converter, which is given

by

Use a ceramic capacitor because it has lower

ESR and smaller size that allows us to ignore

the ESR of the output capacitor. Thus, the

output voltage ripple is given by:

V_TC(V

 V_TC)

IN_MAX

(A) (11)

I_{RMS _MAX} I_{CC _MAX}



V

V_SYS

IN_MAX

1

V_SYS

V_SYS

V

IN

For ICC_MAX=2A, VTC=3V, VIN_MAX=10V, the

maximum ripple current is 1A. Select the input

capacitors so that the temperature rise due to

the ripple current does not exceed 10°C. Use

ceramic capacitors with X5R or X7R dielectrics

because of their low ESR and small

temperature coefficients.

(12)

r 



%

2

8C2 f_SL

In order to guarantee the ±0.5% system voltage

accuracy, the maximum output voltage ripple

must not exceed 0.5% (e.g. 0.1%). The

maximum output voltage ripple occurs at the

minimum system voltage and the maximum

input voltage.

For most applications, use a 10µF capacitor.

Besides, usually a small cap with at least 1uF

(C1) from IN to GND is required to be put as

much close as possible to the IC. For the input

voltage is high to 10V, consider the spike when

input insert, select the input capacitors (both the

22uF and 1uF) in 25V rating.

The output capacitor can be calculated with

Equation (13):

V_{SYS _MIN}

1

V

IN

(13)

C_SYS



2

8 f_SL r

When SYSFB pin is floating, output voltage

ripple is the main concern to select the output

capacitor (C_SYS), refer to Table 5 for detail

selection guide about the SYS capacitance

selection under typical inputs.

Selecting the Output Capacitor

The output capacitor C_SYSfrom the typical

application circuit is in parallel with the SYS

load. C_SYSabsorbs the high-frequency switching

ripple current and smoothes the output voltage.

Its impedance must be much less than that of

Table 5: SYS Capacitance Selection Guide

SPEC

V_IN

SYS Capacitance (C_SYS) Selection

C_{SYS_MIN}(μF) ⁶⁾

When SYSFB is

Floating

C_{SYS_MIN}(μF) ⁶⁾

When SYSFB

is Programmed

V_SYS

Temperature

Characteristic

1

Package

V

IN

C_SYS



2

8 f_SL r

Application

Required

5V

9V

13.6

20

X5R;X7R

Δr=0.1%

L=1μH @V_IN=5V

L=2.2μH @V_IN=9V

Application

Required

13.3

20

NOTE:

6) For different voltage rating, capacitance will have different DC bias characteristic. Suppose a general condition, capacitance drops

40% under V_SYS=4.4V under 10V rating, and 50% at 6.3V rating.

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

When SYSFB is programmed using external

it has the following electrical characteristic:

At 0°C, R_{NTC_Cold}= 27.445kΩ;

resistors, the control loop function is changed.

A zero point is added around the cross over

frequency of the DC gain, and this may result in

the phase margin varied a lot, which may cause

the unstable operation. To avoid this condition,

a minimum capacitance requirement should be

satisfied to make the pole point to compensate

the zero point. This minimum capacitance is

20uF for a general application.

At 50°C, R_{NTC_Hot}= 4.1601kΩ.

The following equations are derived assuming

that the NTC window is between 0°C and 50°C.

According to the above equations to calculate

R_T1=7.15kΩ and R_T2=25.5kΩ.

So, for the SYSFB programmed condition, the

C_SYSshould be selected as max (C_{SYS_MIN}

,

20uF), C_{SYS_MIN}is calculated from the formula of

equation (13), as shown in Table 5. For better

stability margin, select

a

47uF ceramic

capacitor with 6.3V and above voltage rating as

the output capacitor in this case.

Resistor Choose for NTC Sensor

Figure 8 shows an internal resistor divider

reference circuit to limit the low temperature

threshold and high temperature threshold at

65%·VCC and 33.5%·VCC, respectively. For a

given NTC thermistor, select appropriate R_T1

and R_T2to set the NTC window:

Figure 4—NTC Function Block

PCB Layout Guideline

It is important to pay special attention to the

PCB layout to meet specified noise, efficiency

and stability requirements. The following design

considerations can improve circuit performance:

R_T2//R_{NTC_Cold}

R_T1 R_T2//R_{NTC_Cold}VCC

R_T2//R_{NTC_Hot}

R_T1 R_T2//R_{NTC_Hot}VCC

V_THL

(14)



 65%

1) Route the power stage adjacent to their

grounds. Aim to minimize the high-side

switching node (SW, inductor), trace lengths in

the high-current paths and the current sense

resistor trace.

V_THH

(15)



 33.5%

R_{NTC_Hot}is the value of the NTC resistor at high

temperature of the required temperature

operation range, and R_{NTC_Cold}is the value of

the NTC resistor at low temperature.

Keep the switching node short and away from

all small control signals, especially the feedback

network.

The two resistors, R_T1and R_T2, allow the high

temperature limit and low temperature limit to

be programmed independently. With this

feature, the MP2625B can fit most type of NTC

resistor and different temperature operation

range requirements.

Place the input capacitor as close as possible

to the IN and PGND pins.

Place the output inductor close to the IC and

connect the output capacitor between the

inductor and PGND of the IC.

R_T1and R_T2values depend on the type of the

NTC resistor:

2) For high-current applications, the balls for the

power pads (IN, SW, SYS, BATT and PGND)

should be connected to as much copper in the

board as possible. This improves thermal

performance because the board conducts heat

away from the IC.

0.3 R_{NTC_Cold}R_{NTC_Hot}

(16)

R_T2



0.1225R_{NTC_Cold}- 0.4225R_{NTC_Hot}

0.3R_{NTC_Hot}R_{NTC_Cold}

(17)

R_T1



0.2275(R_{NTC_Cold}R_{NTC_Hot}

)

For example, for the thermistor NCP18XH103,

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

3) The PCB should have a ground plane

connected directly to the return of all

components through vias (two vias per

capacitor for power-stage capacitors, one via

per capacitor for small-signal components). It is

also recommended to put vias inside the PGND

pads for the IC, if possible. A star ground

design approach is typically used to keep circuit

block currents isolated (high-power/low-power

small-signal) which reduces noise-coupling and

ground-bounce issues. A single ground plane

for this design gives good results. With this

small layout and a single ground plane, there is

no ground-bounce issue, and having the

components segregated minimizes coupling

between signals.

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

TYPICAL APPLICATION CIRCUITS

ON

OFF

VILIM

M0

M1

EN

5V Input

L

SYS Load

SW

IN

1.0uH

2k

R3

R4

C1

1uF

C3

100nF

CHGOK

C_SYS

BST

SYS

R1

21k

ACOK

VCC

22uF

MP2617B

SYSFB

PGND

R_T1

C_IN

10k

NTC

10uF

C2

R2

I_CHG

10k

BATT

R_T2

10k

1uF

vBATT

TMR

AGND

C_BATT

C_TMR

100nF

ISET

ILIM

22uF

R_ISET

1.05k

R_ILIM

30.9k

0

Figure 9: Typical Charge Application Circuit for 5V input with NTC Resistor Fixed

Table 6: The Key BOM of Figure 9.

Qty

Ref

Value

Description

Package Manufacture

Ceramic Capacitor;10V;

X5R or X7R

1

C_IN

10μF

1206

0603

Any

Ceramic Capacitor;10V;

X5R or X7R

1

C1

C2

1μF

Ceramic Capacitor;6.3V;

X5R or X7R

1μF

0603

Any

Ceramic Capacitor;16V;

X5R or X7R

Ceramic Capacitor;6.3V;

X5R or X7R

1

C3

100nF

0603

Any

C_TMR

Ceramic Capacitor;10V;

X5R or X7R

2

1

C_SYS,C_BATT

R_T1,R_T2

L1

22μF

10k

1206

0603

SMD

Any

Film Resistor;1%

Inductor;1.0uH;Low

DCR;I_SAT>2.8A

1.0μH

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

TYPICAL APPLICATION CIRCUITS

ON

OFF

R5 100k

VILIM

M0

M1

EN

9V Input

L

SYS Load

SW

IN

2.2uH

C3

2k

R3

R4

C1

1uF

BST

SYS

CHGOK

C_SYS

100nF

R1

21k

ACOK

VCC

22uF

C4

R6

26.5k

R7

4.7uF

MP2617B

SYSFB

PGND

R_T1

C_IN

10k

NTC

22uF

C2

R2

I_CHG

10k

BATT

R_T2

10k

1uF

vBATT

TMR

AGND

C_BATT

22uF

C_TMR

100nF

ISET

ILIM

R_ISET

1.05k

R_ILIM

30.9k

0

Figure 10: Typical Charge Application Circuit for 9V Input and 1.5A Input Current Limit

Table 7: The Key BOM of Figure 10.

Qty

Ref

Value

Description

Package Manufacture

Ceramic Capacitor;16V;

X5R or X7R

1

C_IN

22μF

1206

0603

Any

Ceramic Capacitor;16V;

X5R or X7R

1

C1

C2

1μF

Ceramic Capacitor;

6.3V; X5R or X7R

1μF

0603

Any

Ceramic Capacitor;25V;

X5R or X7R

1

2

C3

C4

100nF

4.7μF

100nF

22μF

0603

1206

Any

Ceramic Capacitor;

10V; X5R or X7R

Ceramic Capacitor;

6.3V;X5R or X7R

Ceramic Capacitor;10V;

X5R or X7R

C_TMR

C_SYS,C_BATT

1

3

R6

26.5k

10k

Film Resistor;1%

0603

Any

R_T1,R_T2,R7

Inductor;2.2μH;Low

DCR;I_SAT>6A

1

L1

2.2μH

SMD

Any

MP2617A, MP2617B Rev. 1.23

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MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

PACKAGE INFORMATION

QFN-20 (3mmX4mm)

PIN 1 ID

MARKING

PIN 1 ID

0.10 X 45?TYP

PIN 1 ID

INDEX AREA

TOP VIEW

BOTTOM VIEW

SIDE VIEW

0.10 X 45?

NOTE:

1) ALL DIMENSIONS ARE IN MILLIMETERS.

2) EXPOSED PADDLE SIZE DOES NOT INCLUDE

MOLD FLASH.

3) LEAD COPLANARITY SHALL BE0.10

MILLIMETERS MAX.

4) JEDEC REFERENCE IS MO-220.

5) DRAWING IS NOT TO SCALE.

RECOMMENDED LAND PATTERN

NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third

party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not

assume any legal responsibility for any said applications.

MP2617A, MP2617B Rev. 1.23

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型号：	MP2617AGL
厂家：	MONOLITHIC POWER SYSTEMS
描述：	3A Switching Charger with NVDC Power Path Management For Single Cell Li Battery 电池
文件：	总32页 (文件大小：1824K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

MP2617AGL [MPS]

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