Patent ID: 6909410
Filing Date: 2005-06-21
Classification: G09G

Abstract:
1. A driving circuit for a current-control-type light emitting element having an emission luminance controlled by a current flow in said light emitting element, said driving circuit comprising: a current supply circuit configured to supply a current to said light emitting element with a current; and said current supply circuit comprising: a driving control circuit that controls said current supply circuit, wherein a first terminal of said supply transistor is connected to a first power supply, a second terminal of said supply transistor is connected to a first terminal of said light emitting element via said driving switch and to said driving control circuit via said reference switch, a second terminal of said light emitting element is connected to a second power supply, a gate terminal of said supply transistor is connected to said driving control circuit via said control switch and to a first terminal of said capacitor, and a second terminal of said capacitor is connected to the first terminal of said supply transistor, wherein a path of a current supplied from the first power supply via said supply transistor can be switched between one of a path of an injection current into said light emitting element and a path of a reference current into said driving control circuit, by said driving switch and said reference switch, and a supply-terminal voltage that is a voltage of the second terminal of said supply transistor can be input to said driving control circuit via said reference switch, and wherein, based on the reference current and the supply-terminal voltage input via said reference switch during a reference period in which said driving switch is in an off-state, said reference switch is in an on-state, and said control switch is in an off-state, and the supply-terminal voltage input via said reference switch during a driving period in which said driving switch is in an on-state, said reference switch is in an on-state, said control switch is in an off-state, and a current supplied from the first power supply via said supply transistor flows in said light emitting element as the injection current, said driving control circuit controls a gate-terminal voltage of said supply transistor via said control switch, so that the reference current during the reference period approaches a desired setting current value and that the supply-terminal voltage during the reference period approaches the supply terminal voltage during the driving period.