LVHV Board

The Low-Voltage High-Voltage (LVHV) Board is contained in the water proof housing along with the LAPPD. It receives a 12V line and ground, passed from the rack electronics by way of the water proof cables. It's function is:
  • To produce 3 different low-voltages, using switching power supplies (3.3V , 2.5V , and 1.2V): These low voltages power the trigger board and the ACDC cards (in place of the original linear regulators, which consume too much power)
  • To produce high voltage and divide it down, in order to power the 5 stages of the LAPPD (photocathode, top of entry plate, bottom of entry place, top of exit plate, bottom of exit plate). The maximum voltage will be below 3.5 kV.
  • To serve as a slow-controls interface between the various sensors, power circuits, and communications lines. The LVHV talks to the surface electronics through a CANBUS interface and uses a PIC microcontroller.

The schematics for the board can be found here .

The LVHV can be seen in the context of the system diagram found here.

Tables of the various connector and cable interfaces can be found here and here (we're working on merging and completing these documents)