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The module supports current sensing fuel gauge by default, and conducts current sampling through a
20 mΩ sampling resistor R2.
3.1.3. Reference Design for Power Supply
The power design is very important for the performance of the module. The power supply of the module
should be able to provide sufficient current of 3 A at least. If the voltage difference between the input
voltage and the power supply of the voltage is not very large, it is suggested to use an LDO to supply
power to the module, but the thermal power consumption of the LDO itself needs to be considered. If
there is a big voltage difference between the input voltage and the desired output (VBAT), a buck
converter is recommended.
The following figure illustrates a reference design for +5 V input power source.
VCC_5 V
D1
C1
470 μF
NOTE
1. It is recommended to switch off the power supply when the module is in abnormal state, and then
switch on the power to restart the module.
2. The module supports battery charging function by default. If the above power supply design is
adopted, please make sure the charging function is disabled by software, or connect VBAT to a
Schottky diode in series to avoid the reverse current to the power supply IC.
3.1.4. Voltage Stability Requirements
The recommended power supply voltage of the module is 3.8 V. The power supply performance, such as
load capacity, voltage ripple, etc. will directly influence the module's performance and stability. Under
ultimate conditions, the module may have a transient peak current of up to 3 A. If the power supply
capability is not sufficient, there will be voltage drops. If the voltage drops below 3.25 V, the module will
power down. Therefore, make sure the input voltage VBAT never drops below 3.25 V even when the
current of module reaches 3 A.
SC200K_Series_Hardware_Design
R3
51K
C2
C3
10 μF
100 nF
Q1
R1 4.7K
3V8_EN
R2 47K
Figure 4: Reference Design of Power Supply
L1 2.2 μH
U1
SW
PGND
PGND
SW
AGND
SW
PVIN
VOS
PG
PVIN
FB
PVIN
EN
FSW
SS/TR
DEF
GND
C6
3.3 nF
Smart Module Series
R4
100K
R5
75K
C4
C5
22 μF
100 nF
R6
20K
DC_3V8
35 / 105
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