BQ76942: LD PIN instruction

Zeff Leung

Part Number: BQ76942
Other Parts Discussed in Thread: BQ76952

We use the high-side board for MOSFETs controlling,If we don't use the LD PIN for activating BQ76942 from shutdown mode, can I add a diode between the PACK+ and LD pin with 10k resistor?Is there some effects with this connection?

1 个月前

0 FRANK1 1 个月前

TI__Genius 10710 points

Thank you for contacting TI China E2E forum and choosing our products as part of your solution.
Regarding your query, please give us some time to confirm this issue.

0 FRANK1 1 个月前回复 FRANK1

TI__Genius 10710 points

We are checking, hold on please.

0 Zeff Leung 1 个月前回复 FRANK1

Prodigy 50 points

Any news update?

0 FRANK1 1 个月前回复 Zeff Leung

TI__Genius 10710 points

Thank you for your patience.

LD is used as the reference for the DSG driver and is periodically measured by an ADC. With this diode, the ADC measurement can pull the pin down for a brief period of time, causing the DSG gate to pull down too. I have seen this a few times with other customers, so this diode is strongly recommended against.

0 Zeff Leung 1 个月前回复 FRANK1

Prodigy 50 points

Thank you for your reply;

Do you have the and internal connection diagram between LD PIN and DSG PIN.
We check this file "Pin Equivalent Diagrams for the BQ76952, BQ76942, andBQ769142",but we didn't find any connection about LD PIN and DSG PIN

0 FRANK1 1 个月前回复 Zeff Leung

TI__Genius 10710 points

There is no direct connection between LD and DSG. The part uses the LD voltage as a reference when turning the DSG driver off. The diode would prevent this from happening correctly.

0 Zeff Leung 1 个月前回复 FRANK1

Prodigy 50 points

OK，thank you for your reply.
But we also find another problem.When the discharge mosfet and charge mosfet is in serial,when the CHG is off,and the DSG is on,and then connect a high voltage to the PACK+,the CP1 voltage will be affected,and then the charge mosfet is on,if the current is high,the charge mosfet will be damage.

+1 FRANK1 1 个月前回复 Zeff Leung

TI__Genius 10710 points

For another problem, please raise a new post, then we will support you in that.

This ticket will be closed.

电源管理

电源管理论坛

BQ76942: LD PIN instruction