UCC27714: UCC27714

Hello Ashwani,
I am an applications engineer with TI supporting the UCC27714 and will work to resolve your concerns.
There are a number conditions that may result in the high side driver pulses not being present. I will suggest a few items to confirm.
Confirm that VDD is greater than the recommended maximum of 10V.
Confirm that the LI and HI driver input signals are switching from 0V to > 2.7V.
Confirm that the high side bias, HB to HS pin voltage, is greater than the recommended maximum of 10V.
Confirm that the enable pin is > 2.7V.

Confirm that the power mosfet switch node which is connected to the UCC27714 HS pin is transitioning to ground to allow the HB to HS capacitor to charge for the high side driver bias. This is a common reported issue where customers are testing the IC and Mosfets with no connection to the converter. If the low side Mosfet is not switching resulting in the HS pin switching to ground, the HB to HS capacitor for the high side bias is not adequately charged resulting in the HB-HS bias in the UVLO condition.

Let me know if these suggestions address your concerns.

Regards,
Richard Herring

Thanks Richard for you response. still i am facing some issues regarding Driver IC which i elaborating in detail
1. High SIde PWM is affected when i am applying DC bus voltage above 10Volts.
2.One observation i made is that when i connect some resisitive load with one leg and change the resistance from high value to low value with continuous than at low resistance because of increased current PWm pulse affected.
3 I made 3 phase inverter and observed while checking each leg individually , two legs are properly working but third leg suddenly Short circuited ..
4. We are mainly facing problem with High side PWM only with dc link voltage

Hi Ashwani,

Can you post your schematic and waveforms showing the issue you're having so we can help you solve it?

Hi Ashwani,

It's been a while since we've heard from you, so we must assume you've resolved your issue.

If possible, please post how it was resolved for others to learn from.

If not, let us know, and we will work with you to resolve it.

Hi Don,
some solutions was provided by you as my higher gate pulses were not coming. But your answer partially solved my problem.
Actually problem was in data sheet, as in data sheet 10K resiter is connected on higher side pulses parallel , that was making problem to bootstrap capacitor as it discharge it very fast while we were giving DC bus voltage. I just disconnected that resister and tested the ic with various load conditions .and it is now working fine.