Patent ID: 8283875
Filing Date: 2012-10-09
Classification: H05B

Abstract:
1. A holding current circuit for maintaining at least a holding current in a dimmer, the circuit connectable to the dimmer and connectable to a load connected to draw current from the dimmer, the circuit comprising: a controlled current source connectable to draw current from the dimmer in accordance with a control signal; a conduction monitor operable to generate a conduction monitor signal indicative of a conduction state of the dimmer; a current monitor connected to receive at least a portion of the current drawn by the controlled current source and connectable to receive at least a portion of a load current drawn from the dimmer by the load, the current monitor operable to generate a current monitor signal indicative of a magnitude of the current in the current monitor; a current controller configured to generate the control signal based on the conduction monitor signal and the current monitor signal to cause the controlled current source to draw a supplementary current at least as great as a difference between the holding current and the load current when the dimmer is in conduction and the load current is less than the holding current; and an excess current bypass configured to shunt current in excess of an excess current threshold away from the current monitor.