BQ76952: CFET turn ON delay time

Charles Zhang1

Part Number: BQ76952

Hi Team,

My customer concerns about the CFET temperature when the battery is discharging to the load. In the beginning of discharging, current will flow through CFET's body diode until CFET turns on, the power dissipation on CFET's body diode might lead to thermal issue. Therefore, my customer is now finding the fastest way to turn on CFET during discharging. There are two questions regarding turning on CFET-

1. As described in the datasheet, CEFT can be reenabled when CFETOFF pin is de-asserted by host MCU, how long will it take to turn on CFET by de-asserting CFETOFF pin if no fault condition occurs?

2.CFET can also be turned on by the subcommand- ALL_FETS_ON(), how long will it take to turn on CFET by this subcommand?

Regards,

Charles

over 2 years ago

0 Jose Couso over 2 years ago

TI__Mastermind 27321 points

Hello Charles,

Please refer to 6.9 Device Event Timing in TRM.

Note: The timings described in TRM do not include the delays related to user protections.

Regards,
Jose Couso

0 Charles Zhang1 over 2 years ago in reply to Jose Couso

TI__Expert 3430 points

Hi Jose,

So the delay time would be 250ms in normal mode, is there any way to shorten the turn-on delay of CHG FET?

Regards,

Charles

0 Jose Couso over 2 years ago in reply to Charles Zhang1

TI__Mastermind 27321 points

Hello Charles,

There might be a work-around by controlling the FETs individually using the FET Test mode. It is not recommended to use FET Test mode since it was not intended for normal operation.

Please find an useful thread HERE

Regards,
Jose Couso

Power management

Power management forum

BQ76952: CFET turn ON delay time