BQ25606: BQ25606 work abnormal

Rachel,

Please provide your battery voltage.

Looking at your schematic, your TS pin is configured incorrectly. Please refer to section 8.3.6.4 for proper configuration and substitute the thermistor with a 10k if you do not desire JEITA.

Also, please replace C32 with a 4.7uF capacitor.

Thanks,

Ricardo

Hi Ricardo

I replace the capacitor an the TS pin resistor but the output still abnormal.

1.My battery voltage=4V.

2.If the schematic is incorrect,why can I use a DC source instead of a battery to work normally.

3.I connect the  BAT to the VSYS directly,it seems to work normal，does it cause anyother problem?

Regards,

Hi, please see my comments below:

I am using BQ25606, but it seems to work abnormal.

1.When I only connect battery to BQ25606 but no load in VSYS,VSYS is normal;

2.But when I connect a 100mA load at VSYS,VSYS has no output;

Your 100mA load may have overshoot that triggers protection when load is connected. Can you use a resistor as load and try again?

3.I connect a VBUS input to BQ25606,the VSYS is normal again.However, at this time, if I remove VBUS, the VSYS output is still there. 

This is normal.

4.Then I remove the VBUS input and use a DC power instead of battery,VSYS is normal whether the load is connect or not.

Check if your battery pack protection is triggered. What kind of load do you have? E-load and pure resistor load?

What can cause this issue?

I connect the  BAT to the VSYS directly,it seems to work，does it cause anyother problem?

Battery must be connected to BAT pin to charge.

Thank you!

Hi Hong Mao

1.the battery pack protection is not triggered.Battery voltage is still 4V but the VSYS has no output.

2.The load is pure resistor.

3.What if I connect the battery to the BAT pin and connect the  BAT to the VSYS directly,does it cause anyother problem?

Regards

Hi,

How much capacitance on SYS pin ? and BAT pin?

No, you cannot connect BAT to SYS pin. Those 2 pins must be separated.

Regards,

Hong

Hi 

The capacitors are 20uF on SYS pin and 10uF on BAT pin.

Thanks

Hi everything looks OK. If DC power supply at BAT works but battery does not work. I suspect the battery. Could you compare the waveforms at BAT and SYS when load is added or battery is plugged in? If you connect your load to the battery directly, what is the battery voltage?

What is your load resistance on SYS? How do you connect your load to SYS? If you connect your load on SYS and then apply battery, do you have problem?

Hi, HongMao

Thanks for your patient reply

Here's the waveforms(CH1 for BAT and CH2 for SYS)

1.BAT and SYS when load is added(Powered by DC power supply)

2.BAT and SYS when load is added(Powered by battery)

3.BAT and SYS when battery is plugged in

4.BAT and SYS when connect the load to the battery directly

5.The load resistance on SYS is about 50 Ohm.

6.There is no problem if I connect the load on SYS and then apply battery.

7.The battery has no battery protection board.

Thanks

And I’m using a MOSFET to connect the load to SYS

For #3, the load is connected before insert battery? If yes, I think there is surge current somehow when load is connected to SYS. Do you have a way to measure current from SYS to load when load is connected. From #1 and #2, there is voltage spike observed which should be caused by the surge current.

Hi, HongMao

1.In #3,the load is not connected.That's just the waveform of BAT and SYS when battery is plugged in.

2.I put a 0.01Ohm series resistor between SYS and the load to measure current.Here's the waveform.

SYS current waveform when load is added(Powered by battery)

Is the current 12A according to the waveform? In this case, the BATFET OCP is triggered and turned off.

What can cause the surge current?What can I do to prevent the surge current or turn on the BATFET again?

If it is caused by the surge current,then why do I use DC power supply is no problem?