bq24620 charger for 5 cell LI-poly batteries

swapnil katre

Other Parts Discussed in Thread: BQ24620

i have used the application note of bq24620 and built the pcb for charger. Charger is for VIN=28V, BAT=5-cell Li-Phosphate, Icharge=4A, Ipre-charge=0.125A, Iterm=0.3A.

i have started testing the circuit and observed the STAT and PG led are Glowing, without connecting the Batteries to it. According to datasheet, STAT led should Blink at 0.5hz freq, but it is constantly on.

i have measured the voltages of the Pins which are as follows:-

Power supply of 24.4V is connected with no battery load				Power supply of 24.4V is connected with battery(19.5V) as load



Pin no	name	voltage	unit	Pin no	name	voltage	unit
1	VCC	24.4	V	1	VCC	23.8	V
2	CE	0.2	mV	2	CE	0.1	mV
3	STAT	1.4	mV	3	STAT	0.5	mV
4	TS	0.1	mV	4	TS	0.1	mV
5	PG	0	mV	5	PG	0	mV
6	VREF	0.2	mV	6	VREF	0.2	mV
7	ISET	20.2	mV	7	ISET	32.2	mV
8	VFB	13.5	mV	8	VFB	17	mV
9	SRN	2.9	mV	9	SRN	23.4	mV
10	SRP	3.3	mV	10	SRP	11.2	mV
11	GND	0	mV	11	GND	0	mV
12	REGN	0.5	mV	12	REGN	1.9	mV
13	LODRV	7.9	mV	13	LODRV	0.9	mV
14	PH	2.1	mV	14	PH	6	mV
15	HIDRV	0	mV	15	HIDRV	0	mV
16	BTST	1.1	mV	16	BTST	0.9	mV
	PowerPad				PowerPad