This reference design is a low standby and low ship mode current consumption 16S-17S LiFePO4 Li-ion battery pack design for telecom battery backup and emotorcycles. It was implemented for a 2-layer PCB. The 9S-15S AFE bq76940 monitors the lower 15 cells voltage and a two-channel general purpose amplifier LM2904B monitors the 16th and 17th battery cells voltage. The design protects the battery pack against overvoltage, undervoltage, overcurrent, and overtemperature, and it reduces energy consumption when in standby and shipping mode through a welldesigned auxiliary power supply strategy and a highly efficient, low quiescent current DC/DC converter LM5164, therefore allows longer shipping time and idle time.
Features
- Cost competitive 16S-17S LiFePO4 /Li-ion battery pack solution
- ±5-mV cell voltage sensing accuracy for 16/17S battery cell @ room temperature
- 100-µA current consumption when in standby mode
- 5-µA current consumption when in shipping mode
- Robust and programmable protection, including cell overvoltage and undervoltage, overcurrent discharge, short circuit, overtemperature and undertemperature