PMP10215: PMP10215 not giving 36V output as required

Hi Andre,

When you apply 3.3V on pin 1 of J4, you switch Vout from 18V to 36V, but you should have at least 18V on J1 regardless on the voltage on J4-1.

You can turn ON the converter by switching S1 in the ON position (pin 5 and 6 shorted). If instead S1 is switched to "remote", then the converter can be turned ON and OFF by applying 3.3V to pin 3 of J4.

If the converter doesn't start, even if all conditions above are correct, please check that both following conditions 1 and 2 are met:

1) The voltage on net "+400V" (which is the output of PFC stage, driven by U6) must be higher than 385V (this way U11 enables the second stage, driven by U2).

2) The voltage on net +24Vprim must be > 23V and is has the same value like +24Vswitched (therefore Q5 is ON).

Please consider to measure primary side voltages with a differential probe suitable for high voltage.

Best regards,

Roberto

Hi Roberto,
Thank you for the quick response and support.

in step one, where should be measured 400V, I only measure 309V, do you have any idea what could be the cause?

Best Regards
Andre

Hi Andre,
You should measure ~ 400V between TP15 and TP16: that means your PFC stage is on. If you measure 309V, it looks like the PFC stage is off and 309V is the peak input AC voltage (309V/SQRT(2)=218Vac)). Please check that on pin 7 of U6 (Vcc) you have also 12V.
regards,
Roberto

I see now all pins of U6 is at 0V, it is odd because there is a 12V output at the terminal block, so I would expect U6 to be powered

Hi Andre,
The Vcc voltage for U6, named +12Vswitched, comes from Q7, a linear regulator supplied by +24Vswitched.
Please check that you have ~ 24V on TP23 and also 24V on +24Vswitched (which becomes active once you switch the converter on).
Regards,
Roberto

I only have 20V on TP23
regards
Andre

What is the voltage on TP11? If the voltage on TP11 is also 20V, then the PFC stage should start and have 400V.
Please also check that when you attached Q1, Q2, Q6, D11 and D12 you put an isolator Sil-PAD to avoid short circuit.
Also the heat sink should be isolated from the PCB by adding plastic spacers.
Regards,
Roberto

Q1,Q2 and Q6 are all well soldered in, but no heatsinks are screwed on yet, could the lack of a heat sink in any way be the problem? The boards have not been on for longer than 2 min at a time so never got hot

As long as only small load is applied to 36Vout, there should be no big loss in any FET or diode.
Can you please let me know the voltages on the following point?
TP18, TP23, TP20, TP24, TP11, pin 5 of S1 (of course, each voltage referred to its own ground, primary or secondary).
Thanks,
Roberto

TP18 = 12.5V
TP23 = 20.5V
TP20 = 11.9V
TP24 = 3.3V
TP11 = -20.4V
pin 5 of S1 = 3.3V

Thank you,
Andre

Hello Andre,
All voltages look correct except for TP23 and TP11 (I believe TP11=-20.4V is a typo; it should be +20.4V, right?).
Even with TP23 and TP11 = 20.5V, the PFC stage, supplied with 12.5V should start and you should have 400V.
BTW, since this power supply is intended to also supply the audio section with 12V and 3.3V, can you please add a small load on 12V on secondary side (between pin 1 and 2 of J3)? I would say that a 390 Ohm resistor connected between pin 1 and 2. This way you have at least 10% load on 12V. Please check that the voltage on TP23 goes > 23V (should be 24V...25V).
Check also why, even with 12.5V applied to Vcc of U6 the PFC stage does not work (check gate pulses on gate of Q6).
Regards,
Roberto

I intend to power the TPA3255 reference design with the PMP10215, would I not use J1 to power it or do you recommend 12V?

With a 440 Ohm resistor connected between pins 1 and 2 of J3 TP11 and TP23 go up to 24.1 and 24.2V respectively.

I just now tried measuring all the pins of U6 but shorted the board and had damage, I have more to test though, and they have the exact same problems. I can thus see that before the 440 Ohm resistor was connected no power was supplied to U6, but now there is power supplied

But still now power on J1

*But still no power on J1

Hi Andre,
Yes, you can supply the TPA3255 with 12V and 36V (when generated), since the 12V VDD of TPA3255 has a current consumption of ~ 30mA (14mA in idle mode).
Please remember that you will get the voltage on J1 if all conditions are met at the same time, like Vcc >=12V on U6, Vin of U2 >=23V (+24Vswitched), Vbus (+400V) > 385V.
Regards,
Roberto

Thank you very much Roberto, I will try to load the 12V heavier and see if I get an output. Just one last question, will I get the full power output of the TPA3255 by powering it with 12V?