Patent ID: 8159482

Claim:
A drive circuit for driving an apparatus controlled by a current signal, comprising: a plurality of current signal generation circuits for outputting a current signal to each of a plurality of output units; a current signal output line to which outputs of said plurality of current signal generation circuits are commonly connected; a shut down unit for shutting down a flow of a current signal from said current signal generation circuits to the apparatus; a control circuit for controlling each of said plurality of current signal generation circuits to be a current signal output state capable of evaluating an output of one of said plurality of current signal generation circuits on a basis of current values output through said current signal output line; a correction value output circuit for evaluating the output of said one of said plurality of current signal generation circuits on a basis of the current values output through said current signal output line to output a correction value according to an evaluation result; and a correction circuit for correcting an image signal supplied to said current signal generation circuits based on the output correction value, wherein the control circuit controls the shut down unit so as to shut down the flow of the current signal as it controls the plurality of current signal generation circuits such that a first group of said plurality of current signal generation circuits outputs a first current signal, and a second group of said plurality of current signal generation circuits other than the first group of said plurality of current signal generation circuits outputs a second current signal of a level lower than the first current signal.