US Patent 9743476 Light source control device and light source control method

A light source control device includes a constant-current circuit that collectively supplies a current to a plurality of LEDs, a current detection circuit that divides the plurality of LEDs into groups and detects a current amount of a current supplied to each of the groups, and a microcomputer that detects an open fault in the LEDs on the basis of a ratio of the current amount in each of the groups and controls a current supplied from the constant-current circuit to be reduced in a case where an open fault is detected in the LEDs.