DRV8824 1M-ohm resistor at Charge pump

masahiko shimizu

Guru 11235 points

Other Parts Discussed in Thread: DRV8824

Hi,

Could you tell me the mean of 1M-ohm resistor at Charge pump, please?
This is below picture.

If user does not have this resistor, what will happen?
Must we have this resistor?

Best regards,
Shimizu

over 9 years ago

0 Phil Beard over 9 years ago

TI__Expert 4650 points

Hi Shimizu-san,

I consulted our designer and will respond as soon as I hear back.

0 Phil Beard over 9 years ago in reply to Phil Beard

TI__Expert 4650 points

Shimizu-san,

This resistor should be placed to discharge the charge pump during low-power sleep mode or when the device is powered down.

Not including it could cause the charge pump to stay charged and find a different discharge path through the device.

0 masahiko shimizu over 9 years ago in reply to Phil Beard

Guru 11235 points

Hi,

Thank you for your reply.
Is DRV8824 broken by this discharge current?

Best regards,
Shimizu

0 Rick Duncan over 9 years ago in reply to masahiko shimizu

TI__Guru** 114905 points

Hi Shimizu-san,

The DRV8824 is not damaged by this current. When entering sleep, the high side outputs will turn on for a short period of time, creating a brake (slow decay) condition.
Some customers would like to turn the motor by hand immediately after entering sleep. Adding the resistor allows customers to do so.

0 masahiko shimizu over 9 years ago in reply to Rick Duncan

Guru 11235 points

Hi, Rick-san,

Thank you for always support.
It is very interesting for me.

Does this idea(solution) contribute other motor driver of TI, too?

Best regards,
Shimizu

Motor drivers

Motor drivers forum

DRV8824 1M-ohm resistor at Charge pump