TL494: Short circuit protection alternative design

Mustafa Turhan

Part Number: TL494

Tool/software:

Hello.

I will design a buck converter that can provide up to 8A current at 5 volts. I want to use TL494 for my design but I have some questions. In the typical application circuit the load is floating and short-circuit sense resistor is 100 mOhms which will dissipate a lot of power. How can I have short-circuit protection without making the load float and dissipating power on sense resistor?

Thank you.

Datasheet Link: https://www.ti.com/lit/gpn/TL494

over 1 year ago

0 Hong Huang over 1 year ago

TI__Guru 74115 points

Hi,

You can replace the current sense resistor with a current sense transformer so the power loss of the current resistor is eliminated.

0 Mustafa Turhan over 1 year ago in reply to Hong Huang

Prodigy 30 points

That's an expensive solution. I need something simpler.

0 Hong Huang over 1 year ago in reply to Mustafa Turhan

TI__Guru 74115 points

Hi,

The resistor sensing is the simplest. Other sensing approaches are not as simple as the resistor sensing. You need to decide to use which one and go with it.

0 Mustafa Turhan over 1 year ago in reply to Hong Huang

Prodigy 30 points

Hello,

Thank you. I understand your point. What must the load be floating? When happens when I connect the negative terminal of the converter output to ground in another circuit. Then the sensing voltage will always be zero. Is there way to use the sensing resistor without floating the load?

0 Hong Huang over 1 year ago in reply to Mustafa Turhan

TI__Guru 74115 points

Hi,

If you move the Rsense on top of the load, then the load is not floating. But I am not sure that can help resolve the issue you have. Also, when Rsense on top of the load then you need to have level shift circuit (a differential opamp) to get the singal to the IC.

No simple solution.

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TL494: Short circuit protection alternative design