TL494: Push-pull example circuit with optocoupler isolation

Wiky Liao

Intellectual 1940 points

Part Number: TL494
Other Parts Discussed in Thread: TPA3255

Hi Team,

Our customer require 12V boost to 50V @ 6A to audio amplifier TPA3255, plan to use TL494 with push-pull circuit. However I don't find any example circuit of this application, could you help to share with me? Customer need to do isolation here, thanks.

over 4 years ago

0 Eric Reicher over 4 years ago

TI__Expert 7900 points

Hi Wiky,

Why are they targeting the TL494 (200mA gate drivers)? It is a relatively old device. When I utilize Webench with 12Vin, 50Vo, 6A I see many designs for newer products in the push-pull configuration: for example UCC2808A and UCC3808A. These newer devices have an advantage of much higher gate drive current (1A). Could they use one of these instead?

Regards,

Eric

0 Wiky Liao over 4 years ago in reply to Eric Reicher

TI__Intellectual 1940 points

Hi Eric,

Customer already use this part before and it can work normally, but it is not isolated circuit, so they wish to use isolated circuit in next gen. Use new part require more effort on it, so customer wish keep the same solution.

Do you have TL494 push-pull circuit with isolation? If you have please share to us, thanks.

0 Eric Reicher over 4 years ago in reply to Wiky Liao

TI__Expert 7900 points

Hi Wiky,

I found this Application Note on the TL494. It shows a circuit (and design calculations) to isolate both the output and feedback using the TL494. I think they will benefit from this.

https://www.ti.com/lit/an/slva666/slva666.pdf?ts=1629123299055&ref_url=https%253A%252F%252Fwww.ti.com%252Fsitesearch%252Fdocs%252Funiversalsearch.tsp%253FlangPref%253Den-US%2526searchTerm%253Dslva666%2Bpdf%2526nr%253D13

Regards,

Eric

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TL494: Push-pull example circuit with optocoupler isolation