ST7LITE1 and L9904 problem.

Posted on May 17, 2011 at 10:13

Hi all and thanks for reading this post,

I'm currently working on a driving board for DC brush motor based on ST7LITE1 microcontroller and L9904 driver. I tested the driving stage with L9904 alone which functions correctly but when the driving is done by the MCU, this one made a reset each time the transistors commutate to supply the engine. There is no cross conduction through H bridge and the power supply is sufficiently powerful. The problem persists when I use a separated power supply for the +5V of the microcontrolor. The problem seems to come from an EMC disturbance but I am not sure. One among you did it already test this kind of problem and exists an application note of reference to improve immunity of the ST7LITE1? I thank you by advance for your answer.

Posted on May 17, 2011 at 10:13

Hi,

are you working with LVD (Low Voltage Detector) enabled or not? If yes, try to disable it (acting on the option byte) and let me know the results.

Regards,

Tanio