Shorting them directly across their terminals won't (shouldn't) do any harm but if you set it down on something conductive, it can short to almost anything.
Do you have supply voltage on the MCU?
Do you have supply voltage on the MCU?
I found r99 a 4.7ohm resistor bad. Now I’m back up and running but only getting 15v in at the regulator and 13-14 volts out and lots of noise. Its worse now whatever I did.
The input to the regulator should be 2xB+ minus a 2-diode loss (approximately). If it's not, check the doubler circuit.
So as long as I have 14.4vdc coming in at the power supply, I have 22vdc at the regulator input and 15vdc out.
As I lower the supply voltage, the regulator input and output voltage drops and I start to get weird behavior and noise on the outputs. At 12vdc input at the power terminals, I have 15vdc at the regulator input and 13.5vdc at the output.
I have a nice 40khz square wave coming in to the ucc27524 at appx 8vdc peak to peak. 3.7vrms
The output from the ucc27524 is also 40khz at appx 9vdc peak to peak, 5.3vrms
With the same 12vdc supply voltage I have 9.5vdc at pin 6 (vdd). I can increase that to 11.8 by shorting r96 (4.7ohm) resistor. Which helps bring the voltage up at the regulator but it still isn’t high enough.
This is as far as I have got.
As I lower the supply voltage, the regulator input and output voltage drops and I start to get weird behavior and noise on the outputs. At 12vdc input at the power terminals, I have 15vdc at the regulator input and 13.5vdc at the output.
I have a nice 40khz square wave coming in to the ucc27524 at appx 8vdc peak to peak. 3.7vrms
The output from the ucc27524 is also 40khz at appx 9vdc peak to peak, 5.3vrms
With the same 12vdc supply voltage I have 9.5vdc at pin 6 (vdd). I can increase that to 11.8 by shorting r96 (4.7ohm) resistor. Which helps bring the voltage up at the regulator but it still isn’t high enough.
This is as far as I have got.
That seems like a lot of drop across the 4.7 ohm resistor.
How hot is the 15v regulator getting?
The output of the IC should swing the full supply voltage minus about 1/10 of a volt.
Is the IC heating up?
Do you have the same square wave amplitude on each side of the cap in series with the output of the IC?
How hot is the 15v regulator getting?
The output of the IC should swing the full supply voltage minus about 1/10 of a volt.
Is the IC heating up?
Do you have the same square wave amplitude on each side of the cap in series with the output of the IC?
The regulator is getting very hot to the touch.
The IC is getting very hot. It has been replaced already which did not seem to change anything.
The IC output does swing appx supply voltage . Attached is the IC output with 11.9-12vdc supply voltage.
The IC is getting very hot. It has been replaced already which did not seem to change anything.
The IC output does swing appx supply voltage . Attached is the IC output with 11.9-12vdc supply voltage.
Are any of the op-amps or comparators thwe regulator feeds heating up?
If someone has some hands-on experience with the operating temps of the regulator or other components, please help where you can.
If someone has some hands-on experience with the operating temps of the regulator or other components, please help where you can.
Testing with a thermocouple that came with a cheap current clamp meter. Ambient temp at probe is 66F
ucc27524 is appx. 171F
15v reg 110F
The diodes supplying the 22vdc and 12vdc are 145F and 135F
C39, capicitor inline with u c27524 output is 150F
IC9 Tps7a6601 is 105F
Everything else is appx 80F or less.
ucc27524 is appx. 171F
15v reg 110F
The diodes supplying the 22vdc and 12vdc are 145F and 135F
C39, capicitor inline with u c27524 output is 150F
IC9 Tps7a6601 is 105F
Everything else is appx 80F or less.
Yes here are the updated temps.
ucc27524 is appx. 141F
15v reg 90F
The diodes supplying the 22vdc and 12vdc are 135F and 115F
C39, capicitor inline with u c27524 output is 134F
IC9 Tps7a6601 is 94F
The voltages on the 15v regulator are still low while at 12vdc supply at the terminals.
ucc27524 is appx. 141F
15v reg 90F
The diodes supplying the 22vdc and 12vdc are 135F and 115F
C39, capicitor inline with u c27524 output is 134F
IC9 Tps7a6601 is 94F
The voltages on the 15v regulator are still low while at 12vdc supply at the terminals.
Are those temperatures with the ICs disable (if so, they're not running cool)?
If everything runs cool with the drivers disabled, could you have a bad driver?
Is either one running hotter than the other?
If everything runs cool with the drivers disabled, could you have a bad driver?
Is either one running hotter than the other?
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Yes the last set of temperatures were taken with the driver ICs disabled.
With the driver ICs(si8244bb) enabled IC2 runs 78F and IC4 runs 88F.
Unfortunately, I do not have any si8244bb here to change.
With the drivers disabled I get 16.4vdc input at the regulator and 14.6vdc output.
I still get an increase in voltage on the regulator if I short R96 which increases VDD to the ucc27524 with the driver ICs disabled. Doing this makes the regulator input voltage jump to 18.7vdc.
This makes me think something other than the driver ICs are causing issues, but maybe there is a difference in the drivers causing the small dc offset issue and the temperature difference?
An interesting find is that increasing the supply voltage to 14.6vdc(accidentally overshot 14.4vdc) caused the temperature of the ucc27524 to drop to 88F.
Enabling the driver ICs while at 14.6vdc did allow the Ucc27524 (IC1) to run cooler at 130F that’s 40F cooler than running at 12vdc supply voltage.
With the driver ICs(si8244bb) enabled IC2 runs 78F and IC4 runs 88F.
Unfortunately, I do not have any si8244bb here to change.
With the drivers disabled I get 16.4vdc input at the regulator and 14.6vdc output.
I still get an increase in voltage on the regulator if I short R96 which increases VDD to the ucc27524 with the driver ICs disabled. Doing this makes the regulator input voltage jump to 18.7vdc.
This makes me think something other than the driver ICs are causing issues, but maybe there is a difference in the drivers causing the small dc offset issue and the temperature difference?
An interesting find is that increasing the supply voltage to 14.6vdc(accidentally overshot 14.4vdc) caused the temperature of the ucc27524 to drop to 88F.
Enabling the driver ICs while at 14.6vdc did allow the Ucc27524 (IC1) to run cooler at 130F that’s 40F cooler than running at 12vdc supply voltage.
If you disable the ICs and pull the 15v regulator, does the doubler circuit run as expected (cool and at expected voltages)?
Yes, with the regulator removed and drivers disabled there is no significant measurable heat in any of the doubler circuit.
Furthermore, there is now 27.5vdc on the regulator input pin.
I will order some regulators. The only 15 volt ones I have are 7915.
Furthermore, there is now 27.5vdc on the regulator input pin.
I will order some regulators. The only 15 volt ones I have are 7915.
The regulator may not be the problem. It could be anything fed with the regulator, including the filter caps, the driver ICs, diodes in the driver circuit, op-amps, comparators...
With the regulator in the circuit (driver ICs disabled), do you read any voltage across R3 or R91?
With the regulator in the circuit (driver ICs disabled), do you read any voltage across R3 or R91?
Actually found another used regulator in a donor board and it has the same issue. So maybe not the regulator.