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[SOLVED] SMPS efficiency is less than 45%

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Embedded_Geek

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Hello all,

I have designed a flyback smps of rating 5V 2A. The SMPS is based on TinySwitch276.
Unfortunately the efficiency is less than 45%.
1) How can I increase the efficiency?
2) Is it the transformer which is reducing the efficiency?

Thanks in advance,
Embedded_Geek
 

Find the heat. 10W is going somewhere and is making something hot. What is it?
 
Hi,

How did you measure the efficiency?
Output power is DC, thus easy to measure.
But how did you measure input power?

Klaus
 
I measured the RMS current of the AC input to the SMPS, which was about 102mA. The AC voltage is 230V. Therefore I derived the input power as P = VI = 230*102mA W. Is this not correct?
I measured using true rms clamp meter.
 

Is this not correct?
Not at all. Irms * Vrms = apparent power, not real power. Expect a distortion power factor considerably below unity.
 

Hi,

Either you use a true effective power meter,
or you run the SMPS on 310V DC.
This gives the efficiency as DC/DC converter. The AC/DC efficiency is slightly less.

Klaus
 
Hi,

Either you use a true effective power meter,
or you run the SMPS on 310V DC.
This gives the efficiency as DC/DC converter. The AC/DC efficiency is slightly less.

Klaus

In that case, I can measure after the rectifier in the smps. As the voltage here will be DC. Is this correct?
Thanks.
 

Hi,

You may input DC at the AC side (before the rectifier)then you will take rectifier loss into account.

Klaus
 
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    burai

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