SGM41524 [SGMICRO]
Compact Switch Li+/Poly Battery Charger Safe and Reliable Charging;
| 型号： | SGM41524 |
| 厂家： | 
Shengbang Microelectronics Co, Ltd |
| 描述： | Compact Switch Li+/Poly Battery Charger Safe and Reliable Charging 电池 |
| 文件： | 总16页 (文件大小：828K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SGM41524
Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
GENERAL DESCRIPTION
FEATURES
The SGM41524 is a compact and efficient Lithium ion
(Li+) or Lithium ion polymer (Li+/polymer) battery
charger. It can provide power and charge the single cell
battery of a system typically found in compact portable
device. An internal switching buck converter regulates
the supply input for charging the battery and powering
the system even if the battery is absent. The converter
can also operate as a simple pass-through switch with
no switching if the load and input voltages are close.
● Constant Current, Constant Voltage (CCCV)
Charging with Floating Time-Out Timer
● Constant Current Pre-charge
● Maximum 2.3A Charging for 4.2V to 4.5V Battery
● 1.34MHz Switching Frequency
● Programmable Charge Voltage and Current
● 4.15V Input Voltage Regulation
● Output Voltage Fold-Back Charge Retaining
● Thermal Regulation Options
SGM41524: +115℃
A typical application circuit is shown in Figure 2. The
SGM41524 features resistor programmable constant
current and constant voltage charging capability plus a
charge limiting timer and operates in compliance with
the BAJ/JEITA safety guide. An NTC (β = 3950K) can
be used for battery temperature sensing on top of the
internal junction temperature monitoring. The IND
status output pin can be connected to LEDs to indicate
the operating conditions, such as power input ok (POK),
in charging (CHG), VIN over-voltage (POK and CHG
alternate blinking) and no power/disabled (OFF).
Voltage fold-back on the output is provided to power the
system from the input while retaining battery charge
and preventing overcharge. Input under-voltage
regulation is implemented by reducing the load current
such that VIN stays above a minimum when the source
is weak. Similarly, the die temperature can be regulated
and limited by reducing output power to avoid device or
the circuit board being overheated.
SGM41524C: +55℃
● Typical Peak Efficiency of 92% at 1.5A, VIN = 5V
● -40℃ to +85℃ Operating Temperature Range
● Available in a Green TDFN-2×3-8BL Package
APPLICATIONS
Powering and Charge Control of Systems with 500mAh
to 6000mAh Li+/Polymer Batteries
These features simplify the system design and ensure
safe and reliable operation as well as improved user
experience.
The SGM41524 is delivered in a Green TDFN-2×3-8BL
package. The device operates in -40℃ to +85℃ with
two thermal regulation options for +55℃ or for +115℃.
SG Micro Corp
NOVEMBER 2020 – REV. A. 1
www.sg-micro.com
Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
SGM41524
PACKAGE/ORDERING INFORMATION
SPECIFIED
TEMPERATURE
RANGE
PACKAGE
DESCRIPTION
ORDERING
NUMBER
PACKAGE
MARKING
PACKING
OPTION
MODEL
CBA
XXXX
TDFN-2×3-8BL
TDFN-2×3-8BL
SGM41524YTDC8G/TR
SGM41524CYTDC8G/TR
Tape and Reel, 3000
Tape and Reel, 3000
-40℃ to +85℃
-40℃ to +85℃
SGM41524
CG1
XXXX
MARKING INFORMATION
NOTE: XXXX = Date Code and Trace Code.
Serial Number
Y Y Y
X X X X
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
Voltage Range (with Respect to GND)
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.
VIN (VVBAT = 4V)................................................................6V
VBAT (VIN Open) ................................................................6V
CC, CV, IND, NTC, SW...................................... -0.3V to 6V
Package Thermal Resistance
TDFN-2×3-8BL, θJA.................................................. 90℃/W
Junction Temperature.................................................+150℃
Storage Temperature Range.......................-65℃ to +150℃
Lead Temperature (Soldering, 10s)............................+260℃
ESD Susceptibility
ESD SENSITIVITY CAUTION
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.
HBM, Any Pin to Ground and Power ...........................4000V
CDM ............................................................................1000V
Surge Test
Input Surge Discharge (1) .................................................11V
Input Over-Voltage Clamp ...................8V or 50mA, 24 hours
NOTE:
1. Peak current in IEC61000-4-5 1.2μs/50μs 2Ω waveform.
DISCLAIMER
SG Micro Corp reserves the right to make any change in
RECOMMENDED OPERATING CONDITIONS
Supply Voltage Range ........................................3.5V to 5.5V
CC, CV, IND, NTC ............................................ -0.3V to 5.5V
Charge Current Setting Range ...........................0.3A to 2.3A
Operating Junction Temperature Range......-40℃ to +125℃
Environmental Temperature Range ...............-40℃ to +85℃
circuit design, or specifications without prior notice.
SG Micro Corp
www.sg-micro.com
NOVEMBER 2020
2
Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
SGM41524
PIN CONFIGURATION
(TOP VIEW)
SW
IND
CV
1
2
3
4
GND
VIN
8
7
6
5
EP
NTC
VBAT
CC
TDFN-2×3-8BL
PIN DESCRIPTION
PIN
1
NAME
SW
TYPE
O
FUNCTION
Buck Converter Switching Node. Connect to the output inductor.
Status Indication Output. It can source or sink constant current when powered (charging or
not charging). It can only sink current if no power is applied.
2
IND
O
Charge Voltage Programming Input Pin. Connect a resistor between this pin and ground to
select one of the seven charging voltages.
3
4
5
CV
CC
I
I
I
Charge Current Programming/Charge-Inhibit Input Pin. Connect a resistor between this pin
and GND to program the constant charge current ICC, (RCCSET = K/ICC). Pull up this pin to a
voltage higher than VINH to inhibit and stop charging.
VBAT
Battery Voltage Sense Input.
NTC Temperature Sensing Input. Connect to an NTC thermistor (β = 3950K) with other
6
NTC
I
end grounded and biased to VIN by a 1.5 × RNTC25 resistor. Ground this pin if NTC is not
℃
used.
7
8
VIN
GND
EP
P
G
Power Input Pin.
Ground Reference Pin.
Exposed
Pad
Exposed Pad. Thermal pad is internally grounded and must be connected to the PCB GND
plane.
IC
NOTE:
I = Input, O = Output, G = Ground, P = Power for the Circuit, IC = Internal Connection.
SG Micro Corp
www.sg-micro.com
NOVEMBER 2020
3
Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
SGM41524
ELECTRICAL CHARACTERISTICS
(VVIN = 5V, VVBAT = 3.8V, Full = -40℃ to +85℃, typical values are at TJ = +25℃, unless otherwise noted.)
PARAMETERS
SYMBOL
CONDITIONS
TEMP
+25℃
Full
MIN
5.51
5.49
3.90
3.85
TYP
5.67
5.67
4.04
4.04
15
MAX
5.84
5.85
4.17
4.20
20
UNITS
Over-Voltage Protection Threshold
VOVP
VBAT open, VVIN = 5V to 6V
V
+25℃
Full
Minimum Input Operation Voltage
VIN Supply Current
VCHGm
VBAT open, VVIN = 5V to 4V
V
+25℃
Full
IND open, fold-back mode, RCV = 1kΩ,
set VVBAT = 4.17V, no switching
IQ
μA
μA
μA
15
21
0.1
1.4
+25℃
Full
Fold-back mode, RCV = 1kΩ,
set VVBAT = 4.17V, no switching
ILKGFLD
0.1
1.5
Leakage Current into the VBAT (1)
0.1
1.4
+25℃
Full
ILKG
VIN open, VVBAT = 3V to 4.5V
CV pin connected to GND
0.1
1.5
Charge Loop
4.175
4.145
4.20
4.20
50
4.225
4.255
+25℃
Full
Charge Output Regulation Voltage
Charge Voltage Step
VCHG
V
VSTEP
Full
mV
mV
LDO charge mode, input voltage is
greater than VCHGm
VDROPm
Full
Full
2
20
40
The Minimum Voltage Drop between
VIN and VBAT Required for Switch
Charging
Switch charge mode, input voltage is
greater than VCHGm
VDROPM
120
170
230
mV
mV
Charge Voltage Fold-Back when NTC
Temperature is out of 10℃ to 45℃
Range
Compare with VCHG in 10℃ to 45℃
NTC temperature range
VDEG
Full
50
28
27
30
30
32
33
+25℃
Full
Charge Current Decrease at NTC
Temperature Regulation (1)
As percentage of ICC in 10℃ to 45℃
IDEG
DT1
DT2
DT3
DT4
VFLT
FR
%
%
NTC temperature range
62
63
65
+25℃
Full
5℃ Threshold (1)
As percentage of VVIN
As percentage of VVIN
As percentage of VVIN
As percentage of VVIN
As percentage of VCHG
As percentage of VCHG
As percentage of VCHG
VVIN = 5V, VVBAT < 60% × VCHG
As percentage of VCHG
61
63
66
56
58
59
+25℃
Full
10℃ Threshold (1)
%
55
58
60
21
23
24
+25℃
Full
45℃ Threshold (1)
%
20
23
25
16
17
18
+25℃
Full
55℃ Threshold (1)
%
15
17
19
96.5
96.4
96.8
96.7
94.0
93.9
67
98.0
98.0
97.1
97.1
95.5
95.5
97
99.4
99.5
97.5
97.7
97.0
97.1
128
130
63
+25℃
Full
Floating Charge Timer Start Threshold
Fold-Back Retaining Output Voltage
Recharge Threshold
%
+25℃
Full
%
+25℃
Full
VRR
%
+25℃
Full
Battery Precondition Charge Current
Battery Precondition Threshold Voltage
IPRE
mA
%
65
97
57
60
+25℃
Full
VPRE
56
60
65
NOTE: 1. Parameters guaranteed by product characterization.
SG Micro Corp
www.sg-micro.com
NOVEMBER 2020
4
Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
SGM41524
ELECTRICAL CHARACTERISTICS (continued)
(VVIN = 5V, VVBAT = 3.8V, Full = -40℃ to +85℃, typical values are at TJ = +25℃, unless otherwise noted.)
PARAMETERS
SYMBOL
CONDITIONS
TEMP
MIN
TYP
300
MAX UNITS
Load Pre-charge Current
ILOADPRECHG When power-up at VVBAT < 60% × VCHG
Full
mA
4.23
4.05
9450
9150
5.00
5.00
5.77
ms
+25℃
Full
Load Pre-charge Period
tLOADPRECHG
5.83
10000 10500
10000 10800
+25℃
Full
Charge Current Setting Ratio
Charge Inhibition Voltage Threshold
Fast Charge Current
K
RCC = 10kΩ, K = ICC × RCCSET
V
V
A
Voltage forcing on the CC pin to inhibit
charging
VINH
1.5
0.945
0.915
95
1
1.050
1.080
175
+25℃
Full
ICC
RCC = 10kΩ, VVBAT = 3.8V, VVIN = 5V
1
140
140
92
+25℃
Full
Charge Termination Current Threshold
Floating Charge Termination Time
Input Voltage Regulation Threshold
Thermal Regulation Threshold (1)
IRES
mA
min
V
85
190
77
107
+25℃
Full
tFCOT
74
92
108
4.00
3.98
4.15
4.15
55
4.30
4.32
+25℃
Full
VVBAT = 3.8V, VIN for making charge
current to 0
VINREG
TOTR
TOTR
SGM41524C
℃
℃
℃
℃
SGM41524
115
155
20
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
TSHUT
Temperature increasing
TSHUT_HYST
162
155
192
192
140
140
120
120
3.2
1.34
1.34
222
224
170
200
150
180
+25℃
Full
BAT Voltage Monitoring Period before
Turning into Fold-Back Switch Operation
tMON
ms
+25℃
Full
High-side Switch MOSFET
On-Resistance between VIN and SW
RDS(ON)-H
mΩ
+25℃
Full
Low-side Switch MOSFET
On-Resistance between SW and GND
RDS(ON)-L
IPEAK
fS
mΩ
A
Peak Current Limit
Full
1.13
1.08
1.55
1.56
+25℃
Full
PWM Switching Frequency
Indication Driving
MHz
0.7
0.4
0.6
0.4
162
155
1.3
1.3
1.3
1.3
192
192
1.9
2.5
2.0
2.5
222
224
+25℃
Full
IND Sink Current (1)
IINDSNK
IINDSRC
tBLINK
VVIN = 5V
mA
mA
ms
+25℃
Full
IND Source Current (1)
IND Blink Period
VVIN = 5V
+25℃
Full
Input OVP state
NOTE: 1. Parameters guaranteed by product characterization.
SG Micro Corp
www.sg-micro.com
NOVEMBER 2020
5
Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
SGM41524
TYPICAL PERFORMANCE CHARACTERISTICS
VVIN = 5V, VVBAT = 3.8V, TJ = +25℃, unless otherwise noted.
DCM Mode Switch Waveform
CCM Mode Switch Waveform
VSW
VSW
IL
IL
Time (500ns/div)
Time (500ns/div)
Start-up Charge by VIN, with 3.7V Battery at BAT
Start-up Charge by VIN, with10Ω Resistor at BAT
VBAT
VSW
VBAT
VSW
IL
IL
VIN
VIN
Time (5ms/div)
Time (1ms/div)
Forcing CC = 2V to Disable Charge
Recovery Charge by Release CC
VBAT
VSW
VBAT
VSW
IL
IL
VCC
VCC
Time (50μs/div)
Time (20μs/div)
SG Micro Corp
NOVEMBER 2020
www.sg-micro.com
6
Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
SGM41524
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VVIN = 5V, VVBAT = 3.8V, TJ = +25℃, unless otherwise noted.
Efficiency vs. Charge Current
Charge Current vs. RCC
98
96
94
92
90
88
86
84
2500
2000
1500
1000
500
VBAT = 3.8V
VBAT = 3.8V
500
0
0
1000 1500 2000 2500 3000
Charge Current (mA)
0
0.05
0.1
0.15
0.2
0.25
1/RCC (kΩ)
Battery Precondition Charging
Load Pre-charge
Fast Charging with
Constant Current
Voltage Fold-
Back Retaining
Charging for Constant Voltage
VCHG
98% × VCHG
Floating Charging
Timer Starts
Fast Charge Current
Current
Voltage
Current Falls below
the Termination Level
or Floating Time-Out
60% × VCHG
CHG Indication Stops
Load Current
Curve with Less Load Current
Curve with More Load Current
Load Pre-charge (~300mA)
IRES (Termination Current)
IPRE (Precondition Charge Current)
Figure 1. Charging Voltage/Current Profile
SG Micro Corp
www.sg-micro.com
NOVEMBER 2020
7
Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
SGM41524
TYPICAL APPLICATION
RCHG
CIN
RPOK
L1 2.2μH
System
Load
SW
IND
CV
GND
VIN
1
2
3
4
8
7
6
5
BAT
COUT
5.5V
NTC
VBAT
RB
15kΩ
CC
SGM41524
RNTC
RCV
RCC
10kΩ (β = 3950K)
Figure 2. Typical Application Circuit
FUNCTIONAL BLOCK DIAGRAM
L
2.2μH
SGM41524
IND
SW
System
Load
1
5
2
D
GIS:1
CS
RB
15kΩ
TOTR
VBAT
BAJ/
JEITA
State
Machine
NTC
GM
6
7
RCHG
~5.5V Operation
RPOK
COUT
CCCV Modulator
BAT
VIN
QR
QH
RCV
CV
CC
RNTC
10kΩ
3
4
CIN
QL
ICCI
(β = 3950K)
Reverse Block
GND
RCC
8
Figure 3. Block Diagram
ESSENTIAL SEQUENCE
VVIN normal
VVIN over-voltage
VCHGhys
Charge resumes
Stop blinking
Start to blink
VCHGm
Charge starts
Load pre-charge
before normal charge
Charge stops
IND stops
VINDM
tON_D
Switching stops for over-voltage
VCHGm
tNOR
tret
Figure 4. Essential On/Off Timing
SG Micro Corp
NOVEMBER 2020
www.sg-micro.com
8
Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
SGM41524
FUNCTION DESCRIPTION AND APPLICATION
The SGM41524 is a general purpose stand-alone
switch mode charger device designed for powering
systems using Li+/poly rechargeable batteries. Several
features are provided including charge voltage and
current programming and status indication. Input
voltage and die temperature are constantly monitored
to prevent output power failure. If the input supply
voltage drops too low, the device reduces the output
power to reduce loading on the input and prevent
further drop and power failure. Similarly, if the junction
is overheated by heavy load, the output power is
reduced to prevent thermal shutdown and system
power failure. It is also capable for various charging
Charging Profile and Fold-Back Retaining
The charging profile is shown in Figure 1. When the
battery voltage is less than 0.6VCHG, the output current
is regulated to a low and safe preconditioning level
(IPRE). On the other hand when the input supply is
present and charge is complete, the output goes to the
safe voltage fold-back mode for powering the load. In
this mode, the output current is limited to less than
peak switch current limit (IPEAK) and not to the
programmed charge current limit. Figure 5 shows the
load transient response of the evaluation board circuit
whose charge current is programmed for less than the
load current.
modes
like
constant-current,
constant-voltage,
VBAT
constant-current pre-charging, and trickle charging
(when input source is weak).
This device does not have a separate battery switch to
connect or disconnect the battery from the system
(load). However, it uses voltage fold-back retaining for
battery safety and lifetime extension when the battery is
fully charged and input power is present. With this
method, battery energy loss is lower because there is
no switch in the discharge path. The only disadvantage
is that if the battery voltage is excessively low, then
start the system instantly is not possible because
charge path cannot be separated and it may take a few
minutes to charge the battery and reach to an adequate
voltage level to start the load system.
IBAT
Time (500μs/div)
Figure 5. Load Transient Response in Fold-Back Supply
The input voltage is monitored during charging. If the
source is weak and cannot maintain its voltage under
heavy load, the charging current is reduced to avoid
system power collapse due to input voltage drop.
Power-Up with Low/No Battery
If the battery is not attached or its voltage is less than
60% of VCHG (VVBAT < 0.6VCHG), the device feeds the
VBAT with a current limited to less than 300mA for
about 5ms to pre-charge the battery and system load
before it goes into battery precondition charging state.
This pre-charge period can increase the voltage of a
500μF capacitor (between VBAT and GND) for up to 3V
before the device starts to deliver the lower
preconditioning current (almost 97mA).
The charge is considered full if the battery voltage
exceeds the floating voltage VFLT and the charge
current drops below the end of charge current (IRES) or
if the floating charge timer runs out of time (tFCOT).
When the full charge status is detected, the output will
drop to the fold-back voltage specified by fold-back
retaining output voltage ratio (FR ratio is typically 97.1%
of VCHG as specified in the EC table) and converter
continues to work but indicator shows "not charging". If
the battery voltage is higher than fold-back level, the
switching will stop. VBAT is monitored periodically and
if it drops below that level the buck converter starts to
operate and regulate the output to the fold-back level.
The full charge state is continued until the input power
is recycled or if the battery voltage drops below the
recharge voltage level (VRR).
If the load is started before fast charge phase, the
supply capacity will be limited to the precondition
charge current for a relatively long time. The initial 5ms
pre-charge period can quickly bring the device to the
fast charge or even fold-back phase when there is no
battery attached and provide enough power for the
system operation in a short time.
SG Micro Corp
www.sg-micro.com
NOVEMBER 2020
9
Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
SGM41524
FUNCTION DESCRIPTION AND APPLICATION (continued)
55℃), the device stops charging and when it is too low
(less than 5℃), only the small precondition current is
charged.
If the voltage drop between the input and output (VDROP
)
is small and less than VDROPm, the device goes into
forward diode state and stops switching. Switching is
resumed if the VDROP exceeds VDROPM level. The CHG
indication will turn off if the time of VDROP < VDROPm is
longer than the retaining time (tRET).
Table 2. Temperature Related Charging Control
Charging
Voltage
Charging
Current
Temperature Range
Low range, < 5℃.
V
CHG - 50mV
CHG - 50mV
IRES
Charge Current Programming and Turn Off
Charge current is programmed by RCCSET resistance by
RCCSET = K/ICC where the K is charge current setting
ratio which is typically 10000V as specified in the EC
table.
V
70% ICC
Low charging range, 5℃ to 10℃
Recommended charging range,
10℃ to 45℃
VCHG
ICC
V
CHG - 50mV
70% ICC
0
High charging range, 45℃ to 55℃
High range, > 55℃
—
Pulling the CC pin to a voltage level higher than VINH
turns the device off (disabled). When this pin is
released the device resumes the status before being
inhibited.
NOTE: The VCHG and the ICC (charging voltage and current)
are selected in accordance with the battery's specification.
If NTC feature is not used, connect the NTC pin to
ground. The device checks for grounded NTC pin once
during the start-up when the input voltage is exceeding
2.7V.
Charge Voltage Programming
Charging voltage can be programmed in one of the 7
preset values by setting a voltage on CV pin. A 50μA
current source is internally connected to CV pin.
Programming can be done by directly applying a
voltage to the CV pin, or by connecting a resistor to
GND that results in the same voltage as shown in Table
1.
Indication and Status Reading
The IND output can have 4 states to show different
conditions: (1) Low (sink current) to indicate the input
power is available (or not charging); (2) High (source
current) to indicate the device is in charging; (3) Hi-Z
(open) for indicating no power is available (when VIN
<
Table 1. Conditions for Selecting a Charging Voltage
V
CHGm) or when it is turned off by pulling the CC pin
Charging
Voltage
(V)
4.2
4.25
4.3
Forcing
Voltage
(V)
GND
0.6
Separation
Thresholds
(V)
Grounding
Resistance
(kΩ)
voltage up; and (4) blinking or alternatingly Low and
High (sinking and sourcing current) if an input
over-voltage occurs. IND voltage can be used as a
signal for the host or other circuit for status detection.
< 0.4
Short
12
0.4 to 0.8
0.8 to 1.2
1.2 to 1.6
1.6 to 2.0
2.0 to 2.4
> 2.4
1.0
20
4.35
4.4
1.4
28
Note that in the high impedance state (Hi-Z), the POK
LED and CHG LED are forward biased by the input
voltage (all in series) and they can turn on depending
on the drive current determined by the LED forward
voltages and series resistances.
1.8
36
4.45
4.5
2.2
44
Open
Open
NOTE: Sourcing current out of the CV is 50μA typically.
BAJ/JEITA Charging Extending and Safety
This device implements the battery temperature related
charging control in compliance with the BAJ/JEITA
guide on safe use of secondary Lithium ion batteries.
An NTC (β = 3950K) can be used as shown in Figure 2
(or Figure 3) for battery temperature sensing.
Input Voltage Regulation and Thermal
Regulation
To prevent power shutdown, the output current is
gradually reduced if VIN drops close to the minimum
(VCHGm). Output current eventually reaches to zero
when VIN falls to VCHGm level. Similarly, if the junction
temperature increases close to its maximum (TOTR), the
output current is progressively reduced and will reach
As specified in Table 2, the charging voltage and
current are reduced when the sensed battery
temperature is out of the preferred charging range (10℃
to 45℃). When the temperature is too high (above
to zero when the temperature reaches to TOTR
.
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Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
SGM41524
FUNCTION DESCRIPTION AND APPLICATION (continued)
Equation 4 gives the output capacitor RMS current
Component Selection and Layout
ICOUT when no battery is attached.
Inductor Selection
Small inductors and capacitors can be chosen thanks
to the high operating switching frequency of the
1.34MHz. Select an inductor with a saturation current a
little bit higher than the charging current (ICHG) plus half
the ripple current peak to peak magnitude (IRIPPLE):
IRIPPLE
(4)
ICOUT
=
≈ 0.29×IRIPPLE
2× 3
The RMS ripple voltage in worst case is calculated as:
IRIPPLE
2× π × fS ×COUT
The capacitance should be selected large enough for
meeting the system requirement for acceptable VRPPLE
(5)
VRIPPLE
=
ISAT ≥ ICHG + (1/2) IRIPPLE
(1)
The inductor ripple current depends on the input
voltage (VVBUS), the duty cycle (D = VVBAT/VVBUS), the
switching frequency (fS) and the inductance (L). In CCM
(e.g. full load):
.
In the system design, operation with no battery must be
considered carefully. Typically, the presence of the
battery helps in filtering of the sags and ripples and
provides peak energy demands when load surges
occur. When the battery is absent, a relatively large
capacitor is needed to have proper performance.
VVBUS ×D× 1−D
(
)
(2)
IRIPPLE
=
fS ×L
The maximum inductor ripple current occurs when the
duty cycle (D) is 0.5 or near. Typically, the inductor
ripple is designed in the range between 20% and 40%
of the maximum charging current as a trade-off
between inductor size and efficiency. Smaller inductor
results in higher ripple (AC) current flowing into the
capacitor and switches and can reduce efficiency.
Besides the VRIPPLE requirement, the load starting
inrush current is another factor to consider for output
capacitor selection. If at the beginning the device turns
into fold-back, the converter does not start switching as
the output capacitor holds the voltage higher than the
fold-back retaining voltage. VBAT voltage is monitored
periodically and as long as it is above fold-back voltage,
it is only the output capacitor that powers the system in
the absence of the battery. The capacitance should be
large enough to maintain the VBAT voltage and prevent
dropping below minimum system requirement before
the switching fold-back mode supply operation starts.
The capacitance for fulfilling this requirement is highly
dependent on how the load starts, including its timing,
start current and acceptable voltage drop. Verification
with a prototype is recommended if operation without a
battery is considered.
Input Capacitor
Choose the input capacitance with enough RMS
current rating to decouple input switching AC currents
away from input. Low ESR ceramic capacitor such as
X5R or X7R is preferred for input decoupling. Typically,
10μF capacitance is suitable for 1A to 2A charging
current. Keep the capacitor(s) close to VIN and GND
pins to minimize the parasitic inductance in the input
ripple current circulation path. In the worst-case, the
RMS of the ripple current is half of the DC charging
current (ICHG) when duty cycle is D = 50%. If the
converter does not operate at 50% duty cycle, then the
worst-case occurs when duty cycle is closest to 50%.
The input RMS current (ICIN) can be estimated by
Equation 3.
Layout Guide
1. Place VIN capacitor close to the VIN pin and GND
pin.
2. Place the inductor terminal close to the SW pin and
minimize the copper area of switching node trace. Do
not use multiple layers for this connection.
(3)
ICIN = ICHG × D× 1−D
(
)
Output Capacitor
3. Minimize the return loop area and ripple current path
length through the inductor and the output capacitor(s)
to the device GND pin.
A few factors must be considered to design the output
capacitance. First, the SGM41524 has the internal loop
compensation for the buck converter that is optimized
for ceramic output capacitance larger than 10μF. The
output capacitor (COUT) circulates the output ripple
current and prevents it from going into the battery.
Having AC current in the battery results in extra heating
and lower lifetime.
4．Use copper plane for power GND and place multiple
via between top and bottom GND plane for better heat
dissipation and noise immunity.
SG Micro Corp
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NOVEMBER 2020
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Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
SGM41524
FUNCTION DESCRIPTION AND APPLICATION (continued)
PCB Layout Example
Top Layer
Bottom Layer
Top Solder
Via
L
BAT
CBAT
GND
SW
IND
CV
1
2
3
4
8
7
6
5
GND
VIN
CIN
VIN
LED LED
R = 15kΩ
NTC
VBAT
CC
TOP VIEW
RNTC
R = 3.3kΩ R = 3.3kΩ
Figure 6. Typical PCB Layout
SG Micro Corp
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NOVEMBER 2020
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Compact Switch Li+/Poly Battery Charger
Safe and Reliable Charging
SGM41524
FUNCTION DESCRIPTION AND APPLICATION (continued)
R3
3.3kΩ
R4
3.3kΩ
C2
10μF
L1 2.2μH
System
Load
SW
IND
CV
GND
VIN
1
2
3
4
8
7
6
5
VIN
5.5V
BAT
C1
10μF
SGM41524
NTC
VBAT
R5
15kΩ
CC
R6
R1
0Ω
R2
6.8kΩ
10kΩ (β = 3950K)
Figure 7. Typical Application Circuit, Programmed for Charge Current of ICC = 1.47A, and Voltage of VCHG = 4.20V
Table 3. Bill of Materials for Typical Application Circuit
Designator
U1
Quantity
Description
Size
Maker
Part Number
1
Switch Li+/Poly Battery Charger
TDFN-2×3-8BL
SGMICRO SGM41524/SGM41524C
Ind, 2.2μH, Irms = 4.3A, Isat = 6.1A,
DCR = 40mΩ
L1
1
4.0*4.0*2.0mm
Sunlord
WPN4020H2R2MT
C1, C2
R1
2
1
1
2
1
1
2
Cap, Cerm, 10μF, 10V, X5R
Res, 0Ω, 1%
0603
0603
0603
0603
0603
0603
0603
SAMSUNG
UniOhm
UniOhm
UniOhm
UniOhm
Sunlord
R2
Res, 6.8kΩ, 1%
R3, R4
R5
Res, 3.3kΩ, 5%
Res, 15kΩ, 1%
R6
NTC, 10kΩ, 1%, β = 3950K
Chip Light Emitting Diode, Blue
SDNT1608X103F3950FTF
FC-DA1608BK-470H10
LED1, LED2
Nationstar
REVISION HISTORY
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
NOVEMBER 2020 ‒ REV.A to REV.A.1
Page
Updated Absolute Maximum Ratings and Recommended Operating Conditions sections ...................................................................................2
Changes from Original (DECEMBER 2019) to REV.A
Page
Changed from product preview to production data.............................................................................................................................................All
SG Micro Corp
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NOVEMBER 2020
13
PACKAGE INFORMATION
PACKAGE OUTLINE DIMENSIONS
TDFN-2×3-8BL
D
e
N5
N8
L
k
E
E1
D1
N1
b
N4
BOTTOM VIEW
TOP VIEW
1.63
0.65
1.75
2.95
A
A1
A2
SIDE VIEW
0.25
0.50
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
0.008 REF
1.950
1.530
2.950
1.650
0.200
2.050
1.730
3.050
1.850
0.300
0.077
0.060
0.116
0.065
0.008
0.081
0.068
0.120
0.073
0.012
D1
E
E1
b
e
0.500 BSC
0.250 REF
0.020 BSC
0.010 REF
k
L
0.300
0.450
0.012
0.018
SG Micro Corp
www.sg-micro.com
TX00141.001
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
TDFN-2×3-8BL
7″
9.5
2.30
3.30
1.10
4.0
4.0
2.0
8.0
Q2
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
7″ (Option)
7″
368
442
227
410
224
224
8
18
SG Micro Corp
www.sg-micro.com
TX20000.000
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