Patent ID: 9674918
Date: 2017-06-06
CPC Classifications: H05B,Y02B

Claim:
1. An illumination system comprising: a first light-emitting element column including one of a single first light-emitting element or a plurality of first light-emitting elements connected in series; a second light-emitting element column connected in parallel with the first light-emitting element column, and including one of a single second light-emitting element or a plurality of second light-emitting elements connected in series; a constant current supply that supplies a constant current to a light source unit that includes the first light-emitting element column and the second light-emitting element column; a first detector circuit that is connected in series with the first light-emitting element column, and detects a magnitude of current flowing through the first light-emitting element column; and a current adjuster circuit that adjusts the magnitude of the current flowing through the first light-emitting element column, according to the magnitude of the current detected by the first detector circuit, wherein the current adjuster circuit adjusts the magnitude of the current flowing through the first light-emitting element column to set a magnitude of the current flowing through the second light-emitting element column to zero, when a magnitude of the constant current is less than or equal to a first threshold value.