BQ30Z554-R1: Manual FET control with Manufacturing Access command

Hayden_Hast

Part Number: BQ30Z554-R1

Hi Team,

When entering manual FET control mode by issuing the Manufacturing Access command 0x0022 FET Control, do the FETs always default to the “OFF” state if they were previously in the “ON” state when in normal operation mode? I have noticed in testing that whenever I have issued the 0x0022 FET Control command from normal mode and the FETs are on, they always turn off. Then, when I issue the command again to exit manual FET control mode, the FETs always turn back on.

The reason I am asking is because we are trying to reduce the quiescent current for our pack during an End of Line test step, and we want to turn off the FETs in the least amount of commands as possible.

Thanks for your help with this.

Regards,

Hayden

over 7 years ago

0 David Hien over 7 years ago

TI__Genius 10830 points

Hi Hayden ,
Thank you for your interest in our products. A BMS expert has been assigned to your question.

Regards,
David

0 Batt over 7 years ago in reply to David Hien

TI__Mastermind 42535 points

Hayden,

Yeah, they do. The purpose of MFC is to manually control the fet. The default state is off unless the MFC command is sent.

0 Hayden_Hast over 7 years ago in reply to Batt

TI__Intellectual 1515 points

Batt,

Based on our response, I would assume that when entering manual FET control mode (when manufacturing access 0x022 FET control command is sent), the FETs are turned off. When the manufacturer access 0x0022 FET control command is sent again (when exiting manual FET control mode), the FETs are turned back on?

Is this a correct assumption?

Regards,
Hayden

0 Batt over 7 years ago in reply to Hayden_Hast

TI__Mastermind 42535 points

FET control 0x22 is automatic. MFC is an entirely different command. FET enable 0x22 is a toggle. When fets are off, it turns them on. When they are on, it turns them off. When you enable MFC and send the MFC command, you need to send a specific sequence, command 0x00 and data 0x270C to enable fet control for PCHG, CHG and DSG. Command 0x00 and data 0x043D disables them.

0 Hayden_Hast over 7 years ago in reply to Batt

TI__Intellectual 1515 points

Hi Batt,

Final follow-up question....

Just wanted to confirm the sequence to turn OFF the FETs:

- Send Command 0x00 and data 0x270C [Enable FET control]
- Send Command 0x00 and data 0x0022 [Toggle the FETs to OFF]

To turn the FETs back ON:

- Send Command 0x00 and data 0x0022 [Toggle FETs to ON]
- Send Command 0x00 and data 0x043D [Disable FET control]

Does this look correct? Or does the command 0x0022 automatically enable FET control AND toggle the FETs?

Thanks for all your support,
Hayden

0 Hayden_Hast over 7 years ago in reply to Hayden_Hast

TI__Intellectual 1515 points

Hi Batt,

Any update here?

Regards,
Hayden

0 Batt over 7 years ago in reply to Hayden_Hast

TI__Mastermind 42535 points

Hi Hayden,

Sorry for the delay. The command 0x22 enables fet automatically if they are disabled. After this the FETs are fully under fw control.

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BQ30Z554-R1: Manual FET control with Manufacturing Access command