L6207 - positive output voltage regardless of input signal

[Kamil Wroński]

Hello,

Sorry if this post has the wrong label/location.

I have a problem with L6207 dual bridge motor driver. I am using stm32f031k6 mocrocontroller and L6207 to control two motors. While using the devices on evaluation boards they worked perfectly. The problem appeared when I tried using L6207 without evaluation board - I copied eval board circut onto my PCB and started tests. And then the problem occured. No matter what signal I send from microcontroller to L6207 one motors works perfectly, while on the other one there is always positive voltage on both output pins. I tried connecting the L6207 input pins directly to GDN, but still I got 13V on output pins. In the attachment I share schematic of my L6207 circut. The out A pins work correctly, but I always get positive voltage on pins out B.

 

[Peter BENSCH]

Well, it looks like you have overlooked some small detail. If this circuit is exactly the same as the one you tested with the NUCLEO board, it should work identically. Maybe you drew the circuit correctly but missed some connection in the circuit?

Are you 100% sure that you have checked every single node?

Regards
/Peter

[Kamil Wroński]

I was sure I checked everything but it seems that I missed something (as you suggest). But I couldn't find any mistake in my schematic. I also checked my PCB for any mistakes but still didn't find anything wrong. That's why I decided to write here. Let me repeat that one motor works perfectly fine while the other doesn't and gives positive voltage on both out B pins no matter what is on input pins. It may be possible that I missed something but I don't know what could it be.