Patent ID: 7327091

Claim:
A light-emitting element driving apparatus driving a light-emitting element, comprising: a constant-current circuit including a plurality of constant-current sources that are connected in parallel with each other and are respectively connected in series to a light-emitting element to supply current to the light-emitting element, wherein the plurality of constant-current sources arrange 1st to Nth (N is an integer not smaller than 2) constant-current blocks each including 1st to Mth (M is an integer not smaller than 2) constant-current sources, and a current ratio among the 1st to Mth constant-current sources is substantially identical in all of the constant-current blocks; and a control circuit selectively bringing the 1st to Mth constant-current sources into a valid state based on light-quantity correction data representing valid/invalid states of the 1st to Mth constant-current sources commonly for all of the constant-current blocks, and selectively turning on the 1st to Nth constant-current blocks based on gradation data representing on/off states of the 1st to Nth constant-current blocks, wherein a constant-current source belonging to a turned-on constant-current block and being in a valid state supplies current to the light-emitting element.