BQ24780S: Can not see gate driver PWM's-BQ24780S

Alihan Seker

Part Number: BQ24780S

Hello,

I have designed a circuit that includes BQ24780S IC. My schematic design is almost same with evm module but according to TI Forum I have changed somethings like BATFET and RBFET. TI supporters said these are any effect on working. When I plugged the DC Power supply, I can communicate with IC via SMBUS. My measured values are valid according to evm. But when I set the ChargerVoltage() and ChargerCurrent, There are no gate drive pwm. Both side, HIGH SIDE MOSFET and LOW SIDE MOSFET. HISIDE MOSFET gate is always 0.8V and LOSIDE MOSFET is always LOW(0 Volts). Why I can not see gate driver PWM's? My Charger out is the same with HISIDE MOSFET GATE Signal, 0.8V.

over 1 year ago

0 Alihan Seker over 1 year ago

Prodigy 30 points

0 Pengzhao Zhu over 1 year ago in reply to Alihan Seker

TI__Genius 11385 points

Hi Alihan,

That is a big change because you eliminated the BATFET and the ACFET. It is not a typical application for BQ24780S.

As it is not a typical application for this part, I recommend testing an EVM (modify the EVM to your current design) first to ensure it performs properly in your system.

For your design, trying putting a 1000k resistor from CMSRC and ACDRV and see if it works. However, regardless of result, please check performance first with modified EVM before prototype/mass production commitment.

Thanks,

Peng

0 Alihan Seker over 1 year ago in reply to Pengzhao Zhu

Prodigy 30 points

I solved the problem thank you, Problem is no CMSRC input to start charge. When I connected CMSRC to VIN with 4.7k resistor then I can see the PWM and Vout.

Power management

Power management forum

BQ24780S: Can not see gate driver PWM's-BQ24780S