TopSwitch JX error amplifier ?
Hello,
you do not have a sample solution or application note power source with
classic error amplifier? I thing operation amplifier, precise voltage reference + optron instead of TL431+optron?
My point information for error amplifier and its proposal for TOPSwitchJX
Thank you
Comments
The reason is simple, I need to control the output voltage by DAC. The first option is the voltage of the DAC engage in resistive divider TL431. The second option is to replace the TL431 with error amplifier and DAC used as a voltage reference. The second option seems to me preferable, because it contains only one reference and more accurate than the one in the TL431.
Sure it's expensive, but it would in this case did not play a role.
Then, like I say -- if you want to use op amp the compensation would be identical to that around a TL431 design. The output of op amp drives the cathode of opto led. The anode of led is sourced to output though a series resistor just like a TL431 circuit. You need a 1K resistor across led to bias op amp driver appropriately. The compensation from cathode to reference on TL431 is what you would put around op amp from output to negative (minus) input. of op amp. The only care to take (which is also true of TL431) is that you have enough headroom for VCC of OP amp. If your output is 5V and above you should be OK.
The TL431 regulator circuits shown in our design serve is excellent error amplifer. This is pretty much industry standard. Not sure what advantage you are looking for with op amp. If you want to use op amp it simply bias it appropriately and place the same compensation seen in TL431 examples shownfromwhatever PI reference you should choose.