Wide range input power supply 18-265V

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Hi sir
i am designing wide range input power supply , can i use PI Switch TOP267EG?

what are all the design parameters should i consider for very low input voltage power supply?

The first question to ask here is how much output power?

Power output = 40W

That's possibly too high a power level, but it is a good idea to run a spreadsheet to see. You will need to select a very low reflected voltage (VOR) to stay within duty cycle limits at low line. You will also need to select a very high value of bulk capacitor because of the limited energy storage at low voltage levels. This capacitor will need to be rated for the voltage at high line, so it will be physically very large. You may have trouble meeting the peak primary current requirements.

Because of the low value of reflected voltage, you will need an output diode with a high voltage rating, in order to survive at high line. This is also shown by the spreadsheet..

when I went through your Spreadsheet

with below inputs
18-265V input 30W power supply
with TOP267EN

I'm facing problem in Capacitor CIN. it is showing negative value.


test_design.png51.58 KB

I ran a spreadsheet using TOPJX for your conditions. Unfortunately, 30W is not possible, even with the largest TOPSwitch available. 26W is possible, but it is difficult.
In order to get around the problem you encountered in your spreadsheet, you need to keep on increasing the bulk capacitor value until the negative capacitance goes away, and keep on increasing it until you get a duty cycle value within the rating of the TOPSwitch. In this case, 1200uF was necessary. Keep in mind, these will need to be 400V capacitors in order to hold up at the high input voltage extreme, so they will be physically large. I would recommend 2 X 680 uF to be on the generous side and help out at the low end of the voltage range. The necessary reflected voltage for this design to work is 15V, which means the stress on the rectifiers at 265V will be very high - this is detailed in the attached spreadsheet. This voltage range really pushes the boundaries of flyback design, and will be difficult to get working in practice.

TOPSwitch-JX_18to265V_26W.pdf826.3 KB

Thank you sir for suggestion, ( I am forward to use your TOPSWITCH JX)

As per your comments, i can easily design 15W power supply using TOP266E right?

but i am not able to specify 18-265V voltage and also i cannot select the output numbers ( 2/3 outputs) in spreadsheet. please provide any suggestion for this sir.

Power supply design:
Power output : 15W
Output voltage
; 1) 5V 2A
2) 5V 1A

PI Expert may not allow the input parameters you need. I was able to run a design in PIXLS without too much trouble. However, you will need some extra circuitry if you want to proceed with design. Due to the low input voltage, you will need an extra external current source to charge the control pin, as the internal tap in the TOPSwitch may not be able to supply sufficient current at low voltage to allow the part to start. This external current source would be shut off once the primary bias supply has a chance to come up..

thank you sir for posting spreed sheet. It helped me a lot in understanding for universal design.

Can you please share me the schematic reference/design for the same and for also 10W design.

since i am also going for low power universal supply

Can you please provide

Reference schematic for 18-265V SMPS for low power industrial application please?