UC1625-SP: Low side don't toggle

Hi,

Ashkan Golestani said:

I have Maxon motor connected to the circuit. Low side dont activate and when I rotate the shaft manually. I can monitor the high side toggling to the different phases but Low side steady state at almost zero.

Are you referring to the FETs output or the driver output signals?

I would check the driver output signals first.

Brian

Hi Brian,

Of course I checked the driver output after I didn't see activity on the FET output by isolating the driver. I've explained it in the second part of my initial message.

Thanks

Ash

Hi Ash,

Ashkan Golestani said:

What could prevent the toggling on low side!?

The driver has many more input pins than just the 3 Hall inputs, and without knowing the condition of these inputs, we can't expect to see the output high side and low side toggling.

What are these pins below connected to? The SR flipflop output Q is the pwm that drives the driver upper and lower output. If the Q output is 0 then the FETs are disable regardless the state of the 3 Hall inputs.

Brian

Hello Brian,

Thanks for reply.

AGAIN, they are connected same as the application circuit, Pull-up or cap connected to GND .

Thanks

Ash

Hi Ash,

Thank you for your post! Could you provide a waveform showing the voltage on pin 25 during operation? Also, if you could provide a waveform of one of the hall outputs while also showing the high side toggling that would be helpful.

Regards,

Anthony Lodi

Ashkan Golestani said:

AGAIN, they are connected same as the application circuit, Pull-up or cap connected to GND

To know if the internal PWM signal is generated or not, we need to see the waveform at these pins: 25, 26, 27.

Did you adjust the 1K pot to control the output PWM duty cycle?

Brian