TPS62175: typical application 9.3.3.3

David Park

Expert 5400 points

Part Number: TPS62175

Hi,

There was IC damage issue.

Condition is 1.8V output and 0.5A.

When input is above 20V, IC damage occured.

I thought it was related to minimum on time.

On time is 90ns at 1MHz switching frequency and minimum on time is typically 80ns.

But typical application 9.3.3.3 shows that input range is up to 28V and output is 1.8V.

Is it available?

Next, with increasing output capacitance to 220uF, it is solved.

I don't understand the relation of output capacitance and input voltage range.

Could you advice for this issue?

Thanks.

over 5 years ago

0 Chris Glaser over 5 years ago

TI__Guru*** 142680 points

Hi Park,

Yes, the IC can operate up to 28Vin regardless of what the on time is.

Can you send a waveform of Vin, Vout, SW, and inductor current as Vin goes from 20V to a higher voltage?

0 David Park over 5 years ago in reply to Chris Glaser

TI__Expert 5400 points

Hi Chris,

When above 20V is applied, IC is damaged so I can't check the waveform.

The schematic is attached. feedback resistor is modified for 1.8V output.

Thanks.

0 Chris Glaser over 5 years ago in reply to David Park

TI__Guru*** 142680 points

Thanks for sharing your schematic.

A 47uH inductor is not typically used. As well, the ceramic input cap looks like a quite big package size. Can you send each of their part numbers?

Can you give more detail on how the voltage is increased above 20V? Is this done by the actual system or in a lab setup?

0 Chris Glaser over 5 years ago in reply to Chris Glaser

TI__Guru*** 142680 points

Hi Park,

Were you able to find out the part numbers used or to get a waveform?

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TPS62175: typical application 9.3.3.3