Patent ID: 8222829
Filing Date: 2012-07-17
Classification: H02M,H05B

Abstract:
1. A driver circuit comprising: a primary side circuit receiving rectified AC power; a transformer coupled to the primary side circuit and converting a primary voltage to a secondary voltage which is supplied to a load circuit; a secondary side circuit coupled to the transformer, the secondary side circuit detecting current flowing through the load circuit and feedback-controlling the primary side circuit accordingly; a first capacitor coupled to the secondary side circuit for providing an operation voltage to the secondary side circuit; and a second capacitor coupled to the load circuit for providing an operation voltage to the load circuit and an optocoupler device, wherein the primary side circuit has an enable input for receiving an input duty signal, and when the input duty signal dose not enable the primary side circuit, the first capacitor still provides the operation voltage to the secondary side circuit at least for a predetermined period.