TPS61178: Efficiency and design consideration

Kailun Liu

Part Number: TPS61178

Hi team,

Could you help to check the efficiency when Vin=3V，Vout=20V，Iout=0.3~0.5A?

For such ICs with large input and output voltage gaps, are there any design considerations?

Thanks!

+1 Fergus He 5 months ago

Hi Kailun,

We have the efficiency of 3Vin and 16Vout, the efficiency is around 90% at 0.3A to 0.5A,

For 20Vout, it should be a little lower.

For such large gap from input and output, please consider the minimum ton and of time of the inner switch,

The device may not be able to operate when it reaches the limit.

Best Regards,

Fergus

0 Kailun Liu 5 months ago in reply to Fergus He

Thanks Fergus!

0 Kailun Liu 5 months ago in reply to Fergus He

Hi Fergus,

For TON and TOFF issue, if I set f=1.5MHz，T=1/1.5=666ns.

As setting, D≈87%, TON=666*0.87=580ns; TOFF=666*0.13=86＜140ns. Will it has impact on device operation?

0 Fergus He 5 months ago in reply to Kailun Liu

Hi Kailun,

This is just what I mean, the Toff is less than the device's minimum off time.

It is recommended to reduce the frequency.

Regards,

Fergus

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