TPS54160: minimal inductor value

Jonathan Navor

Expert 7845 points

Part Number: TPS54160

Hi Team,

Good day! Could you help us with our customer. I have shared their full inquiry below.

I am looking for minimal inductance value of inductor in DC/DC converter with TPS54160.

Equation 28 in datasheet specifies the following equation:

Let's assume that my maximal current IOUT in application will be 500 mA. But the current will be variable and sometimes it may be much lower, for example 50 mA. If I calculate the equation with 50 mA, the minimal required inductance will result in 10x higher value than inductance at 500 mA. This would mean using too large inductor.

What would be the correct approach here to calculate the minimal inductor value? What about the high minimal inductance at low currents?

Best regards,

Jonathan

over 1 year ago

+1 Marshall_Beck over 1 year ago

TI__Mastermind 29480 points

Hello Jonathan,

For that equation, you should use the device's max rated DC current specification, 1.5A.

I would also recommend comparing against a webench design.

0 Jonathan Navor over 1 year ago in reply to Marshall_Beck

TI__Expert 7845 points

Hi Marshall,

As per our customer looked into Design spreadsheet (www.ti.com/.../slvc432).
It calculates minimal inductor value (line 93) in the sheet. This is calculated with nominal output current (line 81) which can be adjusted according to the application. It does not count with device's maximal current of 1,5 A (line 59).

Why is it different?

Best regards,

Jonathan

+1 Marshall_Beck over 1 year ago in reply to Jonathan Navor

TI__Mastermind 29480 points

Hello Jonathan,

The way I mentioned is the correct way.

The design calculator, if calculating against application max rated current, and it is a low value, it is impractical.

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TPS54160: minimal inductor value