topic Disabling MC33879 Open Load Detection in Other NXP Products

Disabling MC33879 Open Load Detection

dpendrey — Tue, 11 Sep 2018 01:43:44 GMT

Hi,

I have been using the MC33879 for several years now and it is a great part, but I cannot seem to figure out how to turn the open load detection current off. I am communicating via SPI. I have full control over the outputs of course, but cannot seem to be able to control the open load detection current. Of the two bytes of data required I have tried many different combinations to no avail. Any help in turning it off would be greatly appreciated.

Regards,

David Pendrey

Re: Disabling MC33879 Open Load Detection

dpendrey — Wed, 12 Sep 2018 02:44:50 GMT

To clarify: I do appear to be able to control the current to an extent.

When I do what the user manual says will turn it on, I can measure a 130uA current to ground on the outputs. When I do what the user manual says will turn it off, I can measure a 12uA current to ground on the outputs.

This is significantly less current, but it is still more than nothing and more than enough to produce a voltage reading.

Re: Disabling MC33879 Open Load Detection

TomasVaverka — Thu, 13 Sep 2018 07:46:53 GMT

Hi David,

I assume you are using bits 15-8 of the 16-bit command to turn on (1) or off (0) the open load detection current.

In low-side configuration, the leakage current should not exceed 5uA:

In high-side configuration, the leakage current should not exceed 20uA:

What configuration are you using?

Best regards,

Tomas