Patent ID: 8587203

Claim:
A light source power supply circuit having multiple output channels, comprising: a front end circuit configured to receive an input voltage and provide a regulated front end direct current (DC) voltage; a plurality of voltage converter circuits, each of the voltage converter circuits in the plurality of voltage converter circuits being configured to receive the regulated front end DC voltage and provide a separate associated DC output for an associated one of the multiple output channels; a protection switch coupled between the plurality of voltage converter circuits and the front end circuit, the protection switch having a conducting state to couple the front end DC voltage to the plurality of voltage converter circuits and a non-conducting state to decouple the front end DC voltage from the plurality of voltage converter circuits; a current sense circuit coupled to the plurality of voltage converter circuits, the current sense circuit comprising a current sensor and a bypass switch coupled in parallel with the current sensor, the bypass switch having a conducting state to shunt current around the current sensor and a non-conducting state to allow current to flow through the current sensor, whereby when the bypass switch is in the non-conducting state a voltage across the current sensor establishes a current sense output representative of current through at least one of the voltage converter circuits in the plurality of voltage converter circuits; and a controller circuit configured to place the protection switch in the non-conducting state in response to the current sense output.