Dual precision high voltage supply (follow-up)
Utilizing the Mosfet series PI-rgeulation (explored in my previous project description) with 16-bit precision DACs for set voltages and ADC with Arduino control a practically usable stable supply for various experiments requiring high voltages (e.g. for me photomultiplier operation) has been realized.
In a previous project (https://www.elektormagazine.com/labs/high-voltage-supply) a proof of principle for stable high voltage (HV) series regulation from a raw HV source had been demonstrated. Key elements are 1700V Sic Mosfets as series regulation elements that are driven via optocouplers that generate the Mosfet drive voltage using a series of photodiodes. The feedback was a plain PI stage using an op-amp.
So far so good!
In order to make this suitable to some serious application of well-defined high voltage in experiments (e.g. with photomultipliers, counting tubes …) some extensions and modifications had to be made. Here I report on the making and properties of the full-fledged supply featuring the following properties:
In order to make this suitable to some serious application of well-defined high voltage in experiments (e.g. with photomultipliers, counting tubes …) some extensions and modifications had to be made. Here I report on the making and properties of the full-fledged supply featuring the following properties:
- positive voltage channel <1V … >1500V
- negative voltage channel >-1V… >-1500V
- simultaneous channel operation
- voltage accuracy <0.5V
- rms noise (positive channel) < 20mV (DMM ACrms reading)
- rms noise (negative channel) < 50mV
- “zero-shunt” current measurement 1-1000
- voltage input and monitoring using Arduino driven 16-bit DAC’s and ADC
The main building blocks:
1. analog control and monitoring circuitry
2. raw-voltage supply (here using a 1000V vintage (tube age transformer)
3. microcontroller board with DAC and ADC breakouts
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