2.2 Design Considerations
Auxiliary Power Strategy
With the requests of low current consumption in standby mode and ship mode, this design uses the auxiliary
power strategy shown in Figure 2-2.
BAT+
LM5163
TLV70433 MCU
3.3 V
5 V
5 V
EN
BQ76952
TCAN1044V/TCAN1042HV
RST_SHUT
Figure 2-2. Auxiliary Power Strategy
The design has a 100-V Input, 0.5-A, ultra-low I
Q
synchronous Buck DC/DC converter LM5163 with a low I
Q
LDO TLV704 as the main power source when the system is working in normal mode. The BQ76952 regulator is
configured to 5-V output which is the power source when the system is working in standby mode. The series
diode on the BQ76952 regulator output makes sure all power is from the DC/DC converter in normal mode
preventing the BQ76952 regulator circuits from overheating, so DC/DC output should be designed a little higher
than 5 V, BQ76952 regulator output. Detailed component design guidance is available from the LM5163 and
LM5164 converter quickstart design tool. When the system experiences a serious cell under voltage and must
enter ship mode, the MCU will configure the BQ76952 device to enter shutdown mode through an I2C command
or RST_SHUT PIN and turn off LM5163 output through the EN PIN, which configures the system to very low
current consumption mode. This design supports both charger attach and system detect wake up functions. Both
methods wake up the BQ76952 device and enable normal 5-V regulator output, then the MCU is powered on
and will enable the LM5163 through the EN PIN. The whole system then returns to normal mode.
2.3 Highlighted Products
BQ76952
The BQ76952 device is a highly integrated, high-accuracy battery monitor and protector for 3-series to 16-series
Li-Ion, Li-Polymer, and LiFePO4 battery packs. The device includes a high-accuracy monitoring system, a highly
configurable protection subsystem, and support for autonomous or host controlled cell balancing. Integration
includes high-side charge-pump NFET drivers, dual programmable LDOs for external system use, and a host
communication peripheral supporting 400-kHz I2C, SPI, and HDQ one-wire standards. The BQ76952 device is
available in a 48-pin TQFP package.
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TIDUEY5 – JANUARY 2021
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10s–16s Battery Pack Reference Design With Accurate Cell Measurement and
High-Side MOSFET Control
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