Who makes a good high voltage, high current regulator? Are certain models more silent then others? I would like to make an adjustable voltage regulator for a power amp. What line should I look at? Supposedly Linear makes a great product...since the voltages needed vary, I would like to use a pot to adjust the Vout and I am pretty sure that depending on the voltages needed I may need to source a few. Ideally they will all have the same footprint so once I design the PCB I can just change the regulator and dial in the needed voltage.
Thank you in advance
Thank you in advance
One model is 63vdc per rail and 300VA per toroid. One model is 78vdc and 1000VA. If i use a dual toroid design the IPS and VAS portion is what will be regulated is slightly higher voltage but lower VA. For the toroid on the larger amp it is 85vdc and 100VA. The smaller one will be 70Vdc and 50 to 80VA.
What's the difference? Isn't a floating regulator also a, well, series regulator? You have a circuit we can look at?
Or do you mean a cap multiplier, which is not strictly a regulator.
Jan
The LM317 used to be called a floating regulator, and I used it as such years ago, I have since learned that it is risky to use the basic circuit this way without modification due to the discharged output capacitor appearing as a short and raising the I/O differential voltage above it's operating area
Oh Jan,
You are going to get me into so much trouble doing this. And yes
you are quite correct. Many times we don't think like this. The
device doesn't care what ground is, just that it is there. It doesn't
know if it is 0, zero, or +, minus 100V etc, as long as the regulator
is working within its voltage range and current requirements.
This is something that Bob Pease wrote about and first opened
up my brain to this idea.
So, if I understand it correctly, if we use say a 63VDC device
for a higher voltage, say 100VDC, we would need to reference the
ground @ 37VDC to use the 63VDC device at the 100VDC level.
The device only sees a 63VDC difference,
ground @ 37V + 63V = 100VDC.
You are going to get me into so much trouble doing this. And yes
you are quite correct. Many times we don't think like this. The
device doesn't care what ground is, just that it is there. It doesn't
know if it is 0, zero, or +, minus 100V etc, as long as the regulator
is working within its voltage range and current requirements.
This is something that Bob Pease wrote about and first opened
up my brain to this idea.
So, if I understand it correctly, if we use say a 63VDC device
for a higher voltage, say 100VDC, we would need to reference the
ground @ 37VDC to use the 63VDC device at the 100VDC level.
The device only sees a 63VDC difference,
ground @ 37V + 63V = 100VDC.
Yes. The only thing the device 'knows' is the relative voltages at its pins, and that is what it reacts on.
The LM317 is a good example.
An important thing is to make sure the absolute differences between the pins are not exceeded, for instance at switch on, when the input voltage in your example goes up to say 100V, while the output cap is not yet charged and keeps the output at 0V. That will release most of the internal magic smoke...
A zener across the device from input to output will fix that and help to quickly charge up the output cap to some safe value.
Jan
For preamp/driver stages this is a nice one. Please try it, there is more on this world than the older well known parts with their limitations.
LR8 - Power Management - Linear Regulator ICs
Please take care to choose transformer voltage not so high or adapt the circuit to a higher B+ if possible/necessary. Anyway, carefully calculate/measure and adapt to avoid that the reg needs to dissipate too much. It can deliver 30 mA max. and it needs a minimum dropout voltage of 12V.
TL783 is an older "higher voltage" reg but I have had too many breaking down at power on/off. Can't recommend it although it has higher voltage immunity than LM317.
LR8 - Power Management - Linear Regulator ICs
Please take care to choose transformer voltage not so high or adapt the circuit to a higher B+ if possible/necessary. Anyway, carefully calculate/measure and adapt to avoid that the reg needs to dissipate too much. It can deliver 30 mA max. and it needs a minimum dropout voltage of 12V.
TL783 is an older "higher voltage" reg but I have had too many breaking down at power on/off. Can't recommend it although it has higher voltage immunity than LM317.
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In place of the usual protection diode? Does the adjust pin not require lifting?
Of course the adjust pin must be biased for the required Vout minus the ref voltage (staying with the LM317 example).
BTW This also works for fixed regulators like the LM78xx of course.
And the diodes to protect for reverse biasing should be kept, although if you use a zener from in to out, that automagically provides reverse bias protection as well of course.
Jan
Yes, HV regs are quite sensitive for switch-on overload, especially when the output cap is relatively large. It made for some spectacular events during development of my 2100V regulator ;-)
Jan
2100V at which maximum current ? As a high voltage certified guy I can only mention the dangerous character of HV gear when current is above a few mA (and DC!!). Please work safely !!! Any mistake can be your last one.
Not wanting to exaggerate but I have seen a few DIY tube amplifiers with B+ of over 1000V made very dangerously used in a household with pets and children operated without covers and no PE. The only thing one can do is pull the plug and be the bully at that moment. Many do not fully understand what the risks are. DIYing with such voltages is not something for the casual builder. PE is mandatory as well, certainly with voltages/currents a multiple above the lethal threshold.
Not wanting to exaggerate but I have seen a few DIY tube amplifiers with B+ of over 1000V made very dangerously used in a household with pets and children operated without covers and no PE. The only thing one can do is pull the plug and be the bully at that moment. Many do not fully understand what the risks are. DIYing with such voltages is not something for the casual builder. PE is mandatory as well, certainly with voltages/currents a multiple above the lethal threshold.
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