Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob

Is it acceptable for the sense resistor value to be larger than the recommended datasheet value of 1.2kohm for PROFET+2 devices?

Is it acceptable for the sense resistor value to be larger than the recommended datasheet value of 1.2kohm for PROFET+2 devices?

IFX_Publisher1
Community Manager
Community Manager
Community Manager
250 sign-ins First comment on KBA 250 replies posted

The minimum value of the sense resistor must be respected per the datasheet.  If the value of the sense resistor is too low the power dissipation within the sense circuit may become excessive.

The value of the sense resistor is allowed to be greater than the datasheet recommendation of 1.2kohm.  The main drawback to having a larger sense resistor is that the sense voltage being read by the uC ADC will reach the maximum readable/linear value of 5V at a lower load current (see attachment).  Thus the application will only be able to linearly sense up to lower levels of load current.  Once the sense voltage reaches the uC 5V maximum, then any load current beyond this cannot be distinguished from an overload or short circuit condition.

The EMI susceptibility of the device may also be adversely affected if the sense resistor becomes too high in impedance.  The device EMI performance should be verified if the sense resistor used within the application is much greater than 1.2kohm

0 Likes
221 Views