UCC27714: HO outputs stay on high - EN disabled via pull down

Kuan Huang

Part Number: UCC27714

I have designed in three UCC27714 as the gate drivers for a BLDC ESC. I used the exact schematic as shown on the data sheet. I am experiencing a similar problem of HO staying high around 12v. It stay high all the time, as soon as the VDD is applied, with or without the processor being activated. The EN pin is left float (enable all the time). When driven by the processor, the HO pins do swing from 0 to VCC+12V, then it leved back to 12V. It caused a shoot through. I have four other similar designs using IRF drivers with no such symptom.

Is there a defect on the UCC27714 design?

Casey

over 7 years ago

0 Derek Payne over 7 years ago

TI__Mastermind 33380 points

Hello Casey,

There are multiple schematics shown in the datasheet, can you please help by confirming which one?

Am I understanding you correctly that the EN pin is never driven by the processor, and so it is left floating?

Do you have any oscilloscope waveforms which display the issue you have described?

Regards,

0 Kuan Huang over 7 years ago in reply to Derek Payne

Prodigy 20 points

Hello Derek:

I changed the input HI/LI RC filter and also changed the motor parameters that I downloaded into the processor, then it worked. Will test more under higher voltage and higher load later.

Thanks for the reply.

Regards,

Casey

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0 Derek Payne over 7 years ago in reply to Kuan Huang

TI__Mastermind 33380 points

Hi Casey,

I'm glad to hear that your issue was resolved. I will mark this thread as resolved. Let us know if you encounter further issues.

Regards,

Power management

Power management forum

UCC27714: HO outputs stay on high - EN disabled via pull down