BQ24210: BQ24210 not charging lipo battery

Daniel Berenguer

Part Number: BQ24210

I've built the following circuit based on the BQ24210 IC in order to charge a lipo battery from USB (~5VDC) or a solar panel. I'm first trying to make the circuit work from VBUS (USB) = 5VDC, what is actually injecting 4.75VDC on the VBUS pin.

EN_SOLAR (EN pin) is pulled low all the time by the MCU. VBUS_RDY is also read by the MCU and it stays at 0V when both the USB cable and the battery are connected to the board. However CHG always stays high (D6 OFF), which means that the charger is not charging the battery. I then thought that R8 (R_VDPM) was maybe too low so I removed the resistor for battery tracking mode but the problem persists. The circuit seems to never charge the battery.

Thanks in advance for your help.

over 7 years ago

0 Daniel Berenguer over 7 years ago

Expert 2185 points

I forgot to say that my battery nominal voltage is 3.7V.

Thanks again.

0 Bill Johns over 7 years ago in reply to Daniel Berenguer

TI__Guru* 75806 points

Hello
Are you seeing any current going into the battery? Check voltage on ISET, it is an indication of current to battery.
Other thing to check is the voltage at TS, should be around 0.8V.
Is PG going low?

0 Daniel Berenguer over 7 years ago in reply to Bill Johns

Expert 2185 points

Thanks Bill,

V_ISET is 3.6 mV and V_TS is 0.594 V. Should I resize my resistors?

V_PG is 22 mV with battery and USB power in place.

0 Bill Johns over 7 years ago in reply to Daniel Berenguer

TI__Guru* 75806 points

Sorry for the late reply.
V_TS at 0.594V the NTC should not be a problem.
V_ISET at 3.6mV this would indicate no current going to battery
V_PG at 22mV this looks good and would indicate that input power is OK.

The /CHG pin can be tricky, it will indicate fast charge but will not indicate a recharge event.

Have you looked at voltage and current going to the battery with a scope when power is applied? This may indicate the mode unit is going into.

Power management

Power management forum

BQ24210: BQ24210 not charging lipo battery