Many portable radiation monitors include a Geiger-Mueller tube, a simple, two-terminal, gas-filled detector that generates a pulse each time a radiation event (photon or particle) impinges on the tube’s sensitive volume. The HV power supply for these systems often poses problems. A large portion of the system’s quiescent power consumption occurs in the resistive divider that sets the output-voltage sample. For absolute-minimum power consumption, you must use very high-resistance values for the top portion of the divider, values far beyond the maximum 22MΩ available in most standard resistor lines. High-valued resistors, moreover, complicate the board design and the choice of base material for the board. Component size is also an issue.

This application note explains how a boost converter with a 7-stage voltage-multiplying ladder solves many problems of the HV bias supply.