• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 63 subscribers
  • Views 549 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

UCC27210, output

dailing yu
Prodigy 160 points
Other Parts Discussed in Thread: UCC27210

In the PCB, the capacitor C8 between the HB-HS pins has been moved to close to the two pins.
Excuse me, I use ucc27210 as the driver chip, power supply 12V, the capacitance between the power supply and ground is 1uF, and the capacitance between HB and HS is 0.1uF.
Measurement found:
1. The chip is powered normally;
2. Input pins HI and LI have waveforms, normal;
3. There is a 1V voltage between HB-HS;
4.LO output sometimes fluctuates, HO always outputs low level

How should this be solved? Thank you!

  • 0
    Prodigy 160 points

    Figure 1 shows the output waveforms of LO and HO;

    Figure 2 is a waveform of the LO expansion;

    Figure 3 shows the input waveforms of HI and LI;

    Figure 4 is an expanded waveform of HI and LI;


    Figure 5 shows the waveform of the LO pin when no input signal is added.

  • 0 in reply to dailing yu
    TI__Mastermind 20950 points

    Hello Dailing,

    Thank you for the interest in the UCC27210. For proper operation of the driver outputs, make sure the input signals amplitude is higher than the threaholds, which for the uCC27210 is >5.9V. For the HO to operate the HB-HS capacitor needs to be over the HB UVLO of 8.0V.

    For the HB capacitor to charge the HS pin needs to switch to close to ground which normally happens when the low side FET turns on. Since you only see 1V from HB-HS it does not appear that the HB cap is charging fully. The HO output will not work wit 1V on HB-HS.

    Confirm if the switch node is switching to ground so that the HB cap can charge.

    Confirm if this addresses your question, or you can post additional questions on this thread.

    Regards,

  • 0 in reply to Richard Herring
    Prodigy 160 points

    thank you so much！