I’m using one of these LLC resonant supplies in a tube amp I’m building. It provides
My requirements are well within the supply’s specs even with a 50% derating and it bench tests fine with the loads I need.
I’ve read lots about LLC resonant supplies because they’re fascinating, I want to make some minor mods and I may need to make repairs or improvements if the supply proves unreliable.
I’ve reverse-engineered a schematic for everything but the controller which is on a daughter-board with an opaque coating. Based on all the application notes I’ve read I’m betting it has an L6599 on it.
I may have read lots but I’m still a hobbyist not an electronics engineer. So, I’m hoping someone can help me with some questions.
Each of the outputs looks like this:
What are the parallel resistor and capacitor from the negative terminals to chassis for?
All of the negative terminals will be connected to ground anyway shorting out the parallel resistor and capacitor.
The HT supply looks like this:
I’m guessing that as the output voltage changes the string of diodes (probably zeners) varies the voltages across the optocoupler diodes. The other side of the optocouplers disappears into the mystery controller board.
Why are there 2 optocouplers?
The specs state that the voltage is customisable between 220V and 520V. The jumpers are only giving me 400V, 410V or 420V. I specified 420V to the seller so that’s OK.
However, if I were to need some other voltage, what changes would be required? Swap out the zeners for ones with different voltages?
Finally, I was hoping to use the AC that becomes DC3 (supposed to be good for 50mA) straight off the secondary of the transformer. The requirement is only for 5mA or so.
When I try putting a 2k2 resistor or my planned load across the secondary, I get 0VAC and no DC3 output voltage. Any idea why that might be please?
Thanks, Dave.
- HT: 200V to 520V 300W maximum.
- DC1 and DC2: 2.5V-6.5V adjustable 15W peak 7.5A.
- DC3: fixed output 2.5V-15V, customizable, maximum 10W (not sure how it can be both fixed and customisable!)
- DC4: -10V to -120V 50mA maximum
My requirements are well within the supply’s specs even with a 50% derating and it bench tests fine with the loads I need.
I’ve read lots about LLC resonant supplies because they’re fascinating, I want to make some minor mods and I may need to make repairs or improvements if the supply proves unreliable.
I’ve reverse-engineered a schematic for everything but the controller which is on a daughter-board with an opaque coating. Based on all the application notes I’ve read I’m betting it has an L6599 on it.
I may have read lots but I’m still a hobbyist not an electronics engineer. So, I’m hoping someone can help me with some questions.
Each of the outputs looks like this:
What are the parallel resistor and capacitor from the negative terminals to chassis for?
All of the negative terminals will be connected to ground anyway shorting out the parallel resistor and capacitor.
The HT supply looks like this:
I’m guessing that as the output voltage changes the string of diodes (probably zeners) varies the voltages across the optocoupler diodes. The other side of the optocouplers disappears into the mystery controller board.
Why are there 2 optocouplers?
The specs state that the voltage is customisable between 220V and 520V. The jumpers are only giving me 400V, 410V or 420V. I specified 420V to the seller so that’s OK.
However, if I were to need some other voltage, what changes would be required? Swap out the zeners for ones with different voltages?
Finally, I was hoping to use the AC that becomes DC3 (supposed to be good for 50mA) straight off the secondary of the transformer. The requirement is only for 5mA or so.
When I try putting a 2k2 resistor or my planned load across the secondary, I get 0VAC and no DC3 output voltage. Any idea why that might be please?
Thanks, Dave.
Thanks. I build a lot of tube HiFi equipment and work with high voltages all the time.
The schematic for the power supply is standard and comprehensive. The PCB itself is very well designed and produced.
I'm not a purist and the opportunity to avoid a bulky, heavy and expensive mains transformer and reservoir capacitors is to good not to try out.
The schematic for the power supply is standard and comprehensive. The PCB itself is very well designed and produced.
I'm not a purist and the opportunity to avoid a bulky, heavy and expensive mains transformer and reservoir capacitors is to good not to try out.
🤣
Maybe others can comment, but I think this is an electrical safety requirement. If you have a single chassis device the chassis must be connected to Earth. But I would also be interested in a more authoritative answer.
Thanks for that.
I need 8V out of DC1 and DC2 (DC1 and DC2: 2.5V-6.5V) and that was a simple resistor change on 2 MP2482 buck converters.
I was wondering why I couldn't use the AC voltage off one of the secondaries to drive a little transformer. Probably because I was trying to drive a little toroidal transformer meant for 50Hz with a ~100kHz square wave.
I need 8V out of DC1 and DC2 (DC1 and DC2: 2.5V-6.5V) and that was a simple resistor change on 2 MP2482 buck converters.
I was wondering why I couldn't use the AC voltage off one of the secondaries to drive a little transformer. Probably because I was trying to drive a little toroidal transformer meant for 50Hz with a ~100kHz square wave.
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What a the 8 pin chip on secondary side .make a diagram of it. Especially the d1 dc2 you want to modify