5440

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:
 
-       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