• State TI Thinks Resolved
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 16 views
  • Users 0 members are here
Support feedback
Options
Options
Related

UCC20225: Anomalies at Gate Driver High Side Pulses

Jun Sheng Ow
Prodigy 40 points
Part Number: UCC20225

Tool/software:

Hi TI Elites,

I'm using UCC20225 to drive my two-phase stepper motor. As my understanding gate driver HS and LS are inverting with each other which mean

I expect to see signal on the HS when the LS is being turned on too. But I found out there is extra pulses at the low side when I zoomed in my waveform as shown below.

How does this happen? Could you please provide some advices?


Legends:

Yellow: Motor Output Current 
Cyan: Gate Driver HS 
Red: Gate Driver LS 
Green: Input PWM 
Orange: The other Gate Driver LS 
Blue: Current sense amplifier output (Configured as in-line setup)



Driving Settings:
Motor Supply Voltage: 72V 
Driving Frequency: 100kHz 
Driving Ipeak: 4A

  • 0
    TI__Intellectual 1605 points

    Hi Jun,

    The LS channel (red) appears to be following the correct output structure, but the HS channel (cyan) looks quite different. I noticed that the orange channel (other gate driver LS) appears to be mostly following the expected behavior of what the cyan channel should be outputting.

    The cyan channel also appears to be really high in voltage with peaks of 80V. This is out of datasheet absolute maximum ratings, and could possibly result in gate driver damage. Can you confirm the supply voltage for VDDA (assuming A channel connected to HS), and ensure it is within spec? If it is, I would also recommend to check the HS MOSFET to ensure it is not accidentally supplying voltage to the gate driver HS output channel.

    Best regards,

    Will