top246yn battery charger

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Hi,

please find attached the schematic for battery charger,
3.3V/12A, using TOP246YN,

when the circuit is loaded, it takes about 5A load, after this state the output voltage drops (its on/off state), does the device is returning to auto restart mode, if this is the case, where might be the problem,

for testing such a larger current o/p , whats the resistor load required?

does this follow this rule ,r=3.3V/12A ==?

regards
vivek

AttachmentSize
TOPSwitch-GX_PIDesign1.uds231 KB

I was reviewing your design I do not see any wrong in the file.
I recommend you do the following:
Increase the Values of R1 to approximately 75K/2W. I know the program gives you 24K but I believe is not necessary to use such low value.

Change D5 to a 2 Amps, same kind or ultra fast diode.

Once you have done these changes. Test your power supply.

What I understand when the IOUT (Output Current) is below 5 Amps, the supply regulates at 3.3 VOUT and the supply works as expected. Am I right?

But When the supply reaches 5 Amps IOUT, it goes into auto restart , am I right?

Please check if the problem happens at low line (85VAC) or High line (265VAC) or both.
Check the voltage at the cathode of D5. When change IOUT from 0 to 5 Amps. Your voltage at D5 should be no less that 10 Volts and about no more than 100 mV ripple.

You can reduce the value of R3 for the next lower value available and test the supply to deliver full output power.
Please tell me what are the results after you have done the recommended adjustments.