DRV8312 Bulk Capacitance and Over Current Adjust

Mark Ackerson

Other Parts Discussed in Thread: DRV8312

Customer is considering moving from an ST motor controller to DRV8312. They have the evaluation board controlling their motor.

Questions:

1. Bulk capacitance. The data sheet does not provide specific details on bulk capacitance. Do we offer any rough guidelines? Do you need 2 x 470 uFs or can the customer us 3 x 100 uFs?

2. OC_ADJ pin. Is it possible to set the current limit with a voltage instead of a resistor to ground? Customer would like to use a DAC or filtered PWM output with filter from the MCU instead of adding a digital potentiometer if I want to have software control of the current limit value.

Please advise.

Thanks,

Mark

over 9 years ago

0 Nicholas Oborny over 9 years ago

TI__Mastermind 21320 points

Hi Mark,

1. Bulk capacitance requirement is driven by the application needs, not the driver. See section 10.1 of the datasheet. It is quite difficult to give guidelines without understanding the motor, the power supply, cabling, connectors, PCB layout, etc. We often ballpark 2-4 uF / W, but system testing will need to be done to verify this.

2. Let me look into this and report back.