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I'm using two ADHV4702-1 high voltage op amps for a project. They are configured as a current sink with a class B output amplifier (with some fixes for the crossover distortion). I already have a +/-12V supply for other parts of the circuit (two lead acid batteries), but I'm not sure how I can generate +/-110 volts for the ADHVs. The maximum current is about 25 to 30mA so it's not a high power application, just high voltage. I thought about using batteries for the 110v rails as well, but that needs a ton of batteries in series which I don't have the space for. I tried looking up boost converters that can generate those voltages but had no luck, just ones with positive output voltage. Can you please help me create a circuit that generates those rails?

Here is the full schematic and simulation for the circuit, although not really that important.

enter image description here

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    \$\begingroup\$ How hard have you searched? I don't know what your allowable input voltages are, but it looks like if you search on the Digikey page for DC DC converters, and look at "more filters", and spend the time you need to, you'll find something. \$\endgroup\$ – Scott Seidman Jun 26 at 13:21
  • \$\begingroup\$ I spent a lot of time on mouser without any luck. I didn't search digikey, but I assume they have the same inventory of parts (or very similar). I'll give that a shot too, but if anyone has a solution, please post it. \$\endgroup\$ – OM222O Jun 26 at 13:24
  • \$\begingroup\$ Check digikey. Recom has some DC-DC converters that have outputs in the 100-200V range. Like Scott Seidman said, if you use the filter features on digikey, you should be able to find something that will work. \$\endgroup\$ – newothegreat Jun 26 at 16:07
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It depends on your ripple requirements.

Consider a DC-DC forward converter with a synchronous or diode bridge centre-tapped 15 W supply to meet the load of 3.3W x 2 can operate using a step-up toroidal transformer.

With a turns ratio to create +/- 110Vdc using a sinusoidal or square wave frequency > =50kHz with high coupling to a well balanced centre-tapped ( input and output) for matched bipolar outputs but optical feedback from only one V-output.

Design for 90 % efficiency and accept 80%.

Filtering must include degraded PSRR of the OA, at the switching frequency with harmonics but can be filtered by design specs for impedance ratios with a simulator for non synchronous resonance on Q filter peaks and with steep skirts using Falstad’s Filter designer.

BTW your step response has a 500 Hz resonance.

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  • \$\begingroup\$ can you post a schematic or link to a page with explanations? I didn't quite understand what you wrote. the oscillations aren't a problem as they will be damped by mechanical elements as well. I can also put a capacitor in series with the actuator coil to reduce it if need be. \$\endgroup\$ – OM222O Jun 26 at 15:10
  • \$\begingroup\$ Forward Converters are common .. I don’t have any handy. \$\endgroup\$ – Sunnyskyguy EE75 Jun 26 at 15:14
  • \$\begingroup\$ can you at least name a few ICs that do this? I can't find much by googling DC-DC forward converter. \$\endgroup\$ – OM222O Jun 26 at 15:17
  • \$\begingroup\$ Every PC PSU uses one for multiple outputs but down instead up in voltage. So look there. \$\endgroup\$ – Sunnyskyguy EE75 Jun 26 at 15:19
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    \$\begingroup\$ EMI is not an issue since it's not a commercial product. load won't exceed 25mA per rail which I assume isn't large enough to cause large ripples. again, this is just used as op amp rails, so tolerances aren't that critical. I can even run it at 100V output and leave 10V headroom per rail, so the op amp isn't damaged. input will be lead acid or lipo batteries, so tolerance is very well defined. \$\endgroup\$ – OM222O Jun 26 at 15:53

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