Here is my schematic and layout for the heater, using 6922 or 12au7 tube:
The big inductor is 470uH, the small inductor is 10uh, R21=R22=10k, R23=1k2. Vin =48V. At first, i bought the LM2576 (not HV), soldered it and the amp work fine even though max Vin of LM2576 in the datasheet is only 40V then i figure that i bought wrong version, swap it for LM2576HV but now the output is 48V and the capacitor blow up. I bought another LM2576HVT and try again but the output is still 48V, removed it and make another heater supply in perf board, still got 48V, i rechecked many time but compare to the datasheet, there's nothing wrong. Pls help me!
The big inductor is 470uH, the small inductor is 10uh, R21=R22=10k, R23=1k2. Vin =48V. At first, i bought the LM2576 (not HV), soldered it and the amp work fine even though max Vin of LM2576 in the datasheet is only 40V then i figure that i bought wrong version, swap it for LM2576HV but now the output is 48V and the capacitor blow up. I bought another LM2576HVT and try again but the output is still 48V, removed it and make another heater supply in perf board, still got 48V, i rechecked many time but compare to the datasheet, there's nothing wrong. Pls help me!
If you have it built like your diagram the in and out of the regulator are reversed VIN is the input and VOUT is the output.
The schematic seems mostly correct,except that the feedback needs to be connected to the output..it appears it's connected to the center of the two coils? (Also,why two coils?)
Ahh,or are you trying to L/C filter the output?
The board layout appears to have the feedback connected correctly...but what's up with the two capacitors on the right that appear in series (C1x and C2x -the numbers are cut off.)
Also,a while back a friend was having similar sounding issues with LM2576HV's,and discovered his were fakes. So,beware of that.
I also ran across this a while ago. Fake LM2596HV Voltage Regulator Buck Converter Modules bought on eBay - YouTube
Ahh,or are you trying to L/C filter the output?
The board layout appears to have the feedback connected correctly...but what's up with the two capacitors on the right that appear in series (C1x and C2x -the numbers are cut off.)
Also,a while back a friend was having similar sounding issues with LM2576HV's,and discovered his were fakes. So,beware of that.
I also ran across this a while ago. Fake LM2596HV Voltage Regulator Buck Converter Modules bought on eBay - YouTube
There are versions of the LM2576HV with output voltages of 3.3V 5V etc., and there is the adj version.
Your circuit needs the adj version. Please check that you did not buy a fixed voltage version by accident.
Your circuit needs the adj version. Please check that you did not buy a fixed voltage version by accident.
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