DRV8703-Q1: Rshunt, Ichopp, Over-current

Hi d_zero,

d_zero said:

1) I saw that the DRV8703-Q1 has some fault conditions like detecting the max current.

Please can you tell me how can i adjust the trip, in order to get the fault over-current condition?

Set the fault overcurrent through the VDS control register. The value depends on the RDSon of the FET and the desired overcurrent level.

d_zero said:

2)Please can you explain the Ichop current -> should i set the Ichop to 7A or to 20A ?

The chopping current value is up to you and the system requirements. Please keep in mind there will be some variation from device to device.

d_zero said:

3) what is the right way to size the Rshunt , if i want to measure the max load current ( i assume that the 7A is the max )

Rshunt= (Vso/Av)/Imax = (5V / 20) / 7A = 35mOhm ??

It is up to you to decide what chopping level you want.

Ideally using a low Rshunt value is best. If you can use a 20mOhm with a 2.8V Vref, that is better as it reduces the power in the shunt resistor.

d_zero said:

4) How does now the Rshunt influence the Ichop and the over-current ?

The Rshunt affects the chopping, and can potentially disable overcurrent. If the device is constantly chopping at a lower current, the VDS monitor will not see an overcurrent condition.