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BQ25887: Start of charge

Part Number: BQ25887

Hello,

I'm using BQ25887 charger in my application. I saw condition, when the charger can't start the charge. The only symptom - bit "PowerGood" changes from  0 to 1 and back to 0. It can stay in that condition more than 10 min.

I do the next steps: 

1. Disable watchdog, set IINDPM to 2000mA, and some other minor changes, you can see it in log file. PSEL pin connected to GND, resistor from ILIM to GND are 470Ohm.

2. I'm using 5V, 2A power supply(Rigol DP832). Total resistance from power supply to BQ25887 are quite high, about 800mOhm. 

3. When I connect VBUS to power supply, IINDPM changes to 3000mA, and BQ25887 can't start the charge. I tried to disable ICO. Also, I see voltage drop in VBUS line, about 1.5V for 30uS,  every 30-60mS. It happens only when battery voltage below 6.2V. From datasheet, I see that in that condition ICO starts from IINDPM.

3. When I set IINDPM to 500mA, charge starts, and only after that I can set it back to 3000mA for ICO to optimize current. All working great from that moment.

My question:

Can I use any settings to prevent this situation? Or I need to manually(I2C) change IINDPM when I see that condition?

Thanks!

Best regards,

Ivan Suvorov

BQ25887start.log
Fri Apr 02 18:15:50 MSK 2021

Device Name = bq25887
Firmware Version = 1.00


Sample,DateTime,ElapsedTime,REG00,REG01,REG02,REG03,REG04,REG05,REG06,REG07,REG08,REG09,REG0A,REG0B,REG0C,REG0D,REG0E,REG0F,REG10,REG11,REG12,REG13,REG14,REG15,REG16,REG17,REG19,REG1B,REG1D,REG1F,REG21,REG23,REG25,REG26,REG28,REG29,REG2A,REG2B,REG2C,LogRowTime(ms),LogStatus
1,2021-04-02 18:15:54,4.010,A0,5E,00,2F,70,8D,7B,02,03,F6,00,00,00,00,00,00,00,00,70,00,00,B0,00,0003,0000,02FF,1788,0C18,026B,002B,29,0B61,EA,FF,C0,00,00,568,SUCCESS
2,2021-04-02 18:15:58,8.012,A0,5E,00,39,70,8D,7B,02,03,F6,19,00,30,00,00,01,92,00,70,00,00,B0,00,004F,0000,1365,1774,0C25,026C,002A,29,0B63,EA,FF,C0,00,00,581,SUCCESS
3,2021-04-02 18:16:02,12.012,A0,5E,00,39,70,8D,7B,02,03,F6,00,00,B2,00,00,01,82,00,70,00,00,B0,00,004C,0000,1376,1788,0C21,026D,002A,29,0B5F,EA,FF,C0,00,00,598,SUCCESS
4,2021-04-02 18:16:06,16.027,A0,5E,00,39,70,8D,7B,02,03,F6,19,00,B2,00,00,01,82,00,70,00,00,B0,00,004A,0000,136B,1781,0C20,026D,002A,29,0B61,EA,FF,C0,00,00,583,SUCCESS
5,2021-04-02 18:16:10,20.043,A0,5E,00,39,70,8D,7B,02,03,F6,19,03,30,00,00,01,82,00,70,00,00,B0,00,004E,0000,1368,1788,0C18,026E,002B,29,0B5F,EA,FF,C0,00,00,582,SUCCESS
6,2021-04-02 18:16:14,24.052,A0,5E,00,39,70,8D,7B,02,03,F6,00,00,B2,00,00,01,82,00,70,00,00,B0,00,0046,0000,136B,1781,0C19,026F,002A,29,0B5F,EA,FF,C0,00,00,574,SUCCESS
7,2021-04-02 18:16:18,28.067,A0,5E,00,20,70,8D,7B,02,03,F6,00,43,B4,00,00,41,82,00,70,00,00,B0,00,01C0,0149,1254,17D8,0C55,026E,002B,29,0B87,EA,FF,C0,00,00,574,SUCCESS
8,2021-04-02 18:16:22,32.074,A0,5E,00,20,70,8D,7B,02,03,F6,00,43,B4,00,00,00,00,00,70,00,00,B0,00,01C0,0149,1254,17E1,0C48,026E,002C,29,0B8D,EA,FF,C0,00,00,583,SUCCESS
9,2021-04-02 18:16:26,36.082,A0,5E,00,20,70,8D,7B,02,03,F6,00,43,B4,00,00,00,00,00,70,00,00,B0,00,01C0,014A,1251,17E1,0C40,026D,002C,29,0B8F,EA,FF,C0,00,00,575,SUCCESS