Tony
This project is add-on to the HP1142A power supply adding the HP1143 functionality. The main difference between both units are :
- HP1142A provide +/-15 and +/- 6 V when HP1143A provide +/- 17.3 V
- HP1142A offset is voltage based, where the HP1143A offset is current based +/- 5 mA
- HP1142A has separate signal and power grounds and in HP1143A we have only one
The PCB fit over the existing HP1142 PCB seating on 4 spacers. Attached photos showing where are the 5 connection to the HP1142A board.
The board on the photos is my first version. Here i am uploading revision 2, where i add a differential amplifier to deal with the potential difference between analog and power ground in the HP1142 and also add a trimer allowing the HP1143 offset to be set to 0 independently.
The HP1142A rectifier provide +/- 32 V, and voltage drop on the LM3x7 is significant. With the current design the temperature on the chip is around 70 C far from the max specified 125 but adding a small heatsink may be beneficial.
Dave's Dev Lab
Lithium ION
euchcat