Getting motor driver to work

[Lord_grezington]

Hello

Since the development board was hard to come by for the TB6588 I had some of my own boards made up where I soldered the SM chips myself. However when Vsp goes below 3.1V the motor jumps and draws high current (as though it goes back into DC excitation mode).

I thought it was my soldering that had gone wrong, so I got a PCB assembler to solder the SM IC for me, but again I get the same problem.

The traces for SC, IP and Start all look ok.

I have since got hold a development board and my motor runs perfectly on that, but I am sure that my schematic is almost identical (well the components that matter).

If anyone on here can take a look and hopefully spot something obvious that I have missed I would be very grateful as this little issue is now starting to be a thorn in my side....

I have attached my schematic, data sheet, app note, schematic of dev board and another schematic i have found online.

Thanks

 

[(*steve*)]

What's Vsp?

I see no power handling components (mosfets or transistors) how are you driving the motor?

 

[Lord_grezington]

Hi Steve

This is a motor drive IC, the mosfets and commutation are handled within the IC.

Vsp and an analogue voltage (in this case provided by potentiometer) the IC uses to vary the PWM duty cycle.