1 foot (RTHM) : the between foot and ground foot should access test battery temperature 10 k Ω thermistors. The resistance of thermistors varies exponentially throughout the operating temperature range. In order to properly sample the battery temperature, the change in thermistor resistance will cause the internal 2.3v reference voltage to vary by -3.9mv / ℃. 2-pin (VLO GIC) : precision reference voltage with a value of 5V ± 1%. 0.1 F capacitance shall be connected between the foot and the grounding foot. GND: grounding pin, which is the reference point for the internal reference voltage and all threshold voltages. The emitter of the collector open output transistor is connected to the pin. Pin 4 (VCC) : power supply voltage input pin of the chip. The operating voltage range of the chip is 7. 5 ~ 40V. Between the foot and the 3 feet shall be connected with 1 shunt capacitor. 5 feet (OU T) : output foot of PWM driver. The charging current of the collector open output transistor is 100mA. 6 pin (STAT1) : transistor open collector output terminal, which is the second decoder of charging state. The relationship between charging state and STAT0 and STAT1 is listed in table 1. Table 1 decoding table 7 (STAT0) : transistor open collector output terminal. For logic level 0, the output voltage of the foot is 0.27 v, and the output end is the first decoding point of the charging state. 8 - pin (STATLV) : the charger is at high level in the floating charge state. 9 feet (OVCTAP) : input foot of overcharge current detection comparator.