BQ76942: CHARGE PUMP NOT WORKING

DILEEP SINGH

Part Number: BQ76942

I am not getting why charge pump fail & IC is not operable. Neither communication is working nor charge Pump. Reg1 is also not giving output voltage to drive MCU. It happens randomly. Another IC is working while the same IC is not. Please help me to resolve this issue.

over 4 years ago

0 Luis H. S. over 4 years ago

TI__Mastermind 42060 points

Hello Dileep,

Did the part work initially, or has it always failed? Are you experiencing issues with just this one IC, or have you tried with multiple ICs? If so, how many?

It could be possible that your IC is broken. Could you share your schematic to make sure that everything is okay?

Best Regards,

Luis Hernandez Salomon

0 DILEEP SINGH over 4 years ago in reply to Luis H. S.

Intellectual 340 points

Hi Luis,

I have faced this issue in multiple ICs, even in fresh IC. And sometimes IC stopped working after an restart.

0 Luis H. S. over 4 years ago in reply to DILEEP SINGH

TI__Mastermind 42060 points

Hello Dileep,

Could you share your schematic so we can review it and make sure everything is okay? Are you following the EVM schematic?

Are you using REG1 to also pull-up the communication lines?

Best Regards,

Luis Hernandez Salomon

0 DILEEP SINGH over 4 years ago in reply to Luis H. S.

Intellectual 340 points

Yes I am following EVM Schematic.

0 Luis H. S. over 4 years ago in reply to DILEEP SINGH

TI__Mastermind 42060 points

Hello Dileep,

If you use an external power supply to pull-up the resistors, are you able to obtain communication? Are you using the pre-regulator REG0 to power the LDOs? Or are you using an external supply?

Did you OTP program the IC to have REG0/REG1 enabled by default? If your IC was not OTP programmed, it would revert to the default factory settings after a restart.

Best Regards,

Luis Hernandez Salomon

0 DILEEP SINGH over 4 years ago in reply to Luis H. S.

Intellectual 340 points

Hi Luis,

I am using BQ7695202. In that case REG0 and REG1 should be enabled by default. On the other hand I am also using external power supply.

My design is working fine. But as I asked earlier in some cases some of the newer ICs are neither capable of delivering voltage to the regulator nor capable of creating charge pump voltage. And in that case I2C communication is also non-functional.

0 Luis H. S. over 4 years ago in reply to DILEEP SINGH

TI__Mastermind 42060 points

Hello Dileep,

Do you measure a voltage in REG18 and CP1? The voltage from REG18 to V_SS should be ~1.8-V. The voltage of CP1 to V_SS should be your cell stack voltage + 11-V (Or just 11-V if measuring voltage across the CP1 capacitor).

Do you have any ICs that work with no issues? It is odd that this is happening to some ICs and others not. Could you please share your schematic so we may review it to make sure everything is okay?

Best Regards,

Luis Hernandez Salomon

0 DILEEP SINGH over 4 years ago in reply to Luis H. S.

Intellectual 340 points

Yes i have measured but in some ICs it does not generate charge pump voltage. Yes I have some ICs that works without any issue.

0 Luis H. S. over 4 years ago in reply to DILEEP SINGH

TI__Mastermind 42060 points

Hello Dileep,

Can you upload a higher resolution picture of the schematic? I am not able to read the values of the parts.

If some are working, then it is possible that there is something damaging the ICs. Do you see your IC not working after a discharge or charge event? Is your working environment ESD safe?

Best Regards,

Luis Hernandez Salomon

0 DILEEP SINGH over 4 years ago in reply to Luis H. S.

Intellectual 340 points

Hi,

Some IC's are not working right after assembling board.

0 Luis H. S. over 4 years ago in reply to DILEEP SINGH

TI__Mastermind 42060 points

Hello Dileep,

Are the devices woken after assembly? Do you see a short across the CP1 capacitor?

Could you upload a higher resolution picture of the schematic? It is hard to know what could be wrong without seeing the schematic.

Best Regards,

Luis Hernandez Salomon

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BQ76942: CHARGE PUMP NOT WORKING