Patent ID: 9338843
Filing Date: 2016-05-10
CPC Classification: H02M,H05B

Claim Text:
1. A circuit for use in driving at least one light emitting diode (LED), the circuit comprising: an input rectifier for receiving an input AC signal; a power factor correction (PFC) subcircuit for receiving an output of said rectifier and for shaping said output of said rectifier into a sinusoidal waveform; a voltage conversion subcircuit for receiving an output of said power factor correction subcircuit and for providing a constant DC current to said at least one LED; and a single semiconductor switch for providing a high frequency pulsating triangular current at an output of said rectifier; wherein said power factor correction subcircuit is coupled between said rectifier and said voltage conversion subcircuit and ground; said power factor correction subcircuit is devoid of other semiconductor switches other than said single semiconductor switch; said single semiconductor switch is coupled between ground and one of said voltage conversion subcircuit or said power factor correction subcircuit; and said power factor correction subcircuit comprises: wherein said voltage conversion subcircuit comprises: a first conversion diode; a second conversion diode; a first conversion capacitor; a second conversion capacitor; a conversion inductor; wherein said first conversion diode is coupled between said PFC subcircuit and a first coupling node; said first conversion capacitor is coupled between said first coupling node and a second coupling node; said second conversion diode is coupled between said first coupling node and said second coupling node; said conversion inductor is coupled between said first coupling node and a first output node; said second conversion capacitor is coupled between said first output node and said second coupling node; said LED is coupled between said first output node and said second coupling node; and said semiconductor switch is coupled between said second coupling node and ground.