DRV8850 Range

Hi Dorian,

What VCC voltage are you using?
What do you intend to do with the voltage provided by VPROPI?

We will investigate your question once we have this information.

Have you considered using the DRV8832?

Good morning Rick,

the VCC voltage will come from a 3.6V Battery, so it will be between 3.75 and 3.25V.
The voltage from VPROPI will go directly to the adc of the µC.

The DRV8832 seens to be an very interesting Part. But the maximal offstate leakage current (-/+ 20µA) is to much for my application. My device has to operate 10 years with one battery, so the quiescent current should be only a few µA.

I've been looking through all the  "Brushed DC Drivers with FETs". The parts that suits best is the DRV8837, but the need of a high precision current sense (1%) made me look again. Alternatives for me would be only the DRV8833, which consumes a little more current, and the DRV8850.

With the Information provided, would it be possible to measure a current of 20mA precisely with the DRV8850?

Best regards

Dorian

Hi Dorian,

The DRV8837 does not require a current sense resistor. The device cannot regulate current, but does have protection features such as overcurrent and overtemperature. The sleep current is small also.

Is there a reason that you need to monitor such small current?

Hi Rick,

yes i know. In the current prototype we are using the DRV8837, but if the Driver had an integrated current sense (like the DRV8850)  it would be even better. The Problem with the DRV8837 is that it only has a common ground, for the load and it's own circuitry, so a high side current sense should be installed (as VM and VCC are separated).  We are using the H-Bridge Drivers to excite a coil for a magentic field, and the current on the coil is only between 20 and 30 mA, depending on the temperature. And we need accurate current information, to deduct the mangetic field from that information (we cannot measure the magenetic field separately)

Hello Rick

sorry to bother you again. But could you confirm whether or not i can measure currents between 20 and 30mA acurrately with the DRV8850?

Best regards

Dorian Hildebrandt

Hi Dorian,

What do you consider accurately?

We will have to check and get back to you.

Good morning Rick

a accuracy of 1% (oder better) would be good for the application.

Thank you.

Hi Dorian,

The VPROPI does not have that level of accuracy. At best you could expect 10%.

If you need 1% or better, it is suggested to use an external amplifier.

Hello Rick

thank you for the Information.

Best regards

Dorian