Hi Phil,
Thank you for your response. For current, I can directly see the current output from the power supply. That's why I can read 0.45A and 2.4A for each driver bank.
If I understand OCP correctly, the tblank time of OCP is in nano second level, but what I experienced is after 10s, the output current ramps up from 0.45A to 2.4A.
Sorry I didn't capture the voltage scope. In this case, I found the output voltage on the driver has 21V spikes (0.45A output current at the same time), and then go to 12V and Low (2.4A output current which is normal). I applied 100% duty-cycle PWM as my input. In other tests, there is no current through the TECs if I use other duty-cycle (50%).
I found out the bulk cap(220uF) is a key factor for motor driver, what is the purpose for the bulk cap? Is it critical for TEC circuit?
I'll appreciate your suggestions.
Thank you,
Kevin