| 摘要 |
A first driver switches on and off a driving current ILED according to a first pulse signal which is pulse-width modulated according to an externally supplied target luminance level of a light emitting element. An oscillator generates a cyclic signal SOSC having a predetermined frequency. A pulse modulator generates a second pulse signal which is switched to an on level that corresponds to the on state of a switching transistor in synchronization with the cyclic signal SOSC, and which is switched to an off level that corresponds to the off state according to a feedback voltage. A second driver switches on and off the switching transistor according to the second pulse signal. The oscillator is configured to be reset according to a first edge which is transition of the first pulse signal from a first level that corresponds to the off state to a second level that corresponds to the on state. |
