Patent ID: 7619365
Filing Date: 2009-11-17
Classification: H02M,H03K,H05B,Y02B

Abstract:
1. A load control device, for controlling the amount of power delivered to an electrical load from an AC power source, comprising: a first controllably conductive device operable to conduct current from the source to the load during a positive half-cycle of the AC power source, the first controllably conductive device having a first control input to render the first controllably conductive device conductive and non-conductive; a second controllably conductive device operable to conduct current from the source to the load during a negative half-cycle of the AC power source, the second controllably conductive device having a second control input to render the second controllably conductive device conductive and non-conductive; a control circuit operable to independently render the first and second controllably conductive devices conductive and non-conductive; a first variable drive circuit coupled in series electrical connection with the first control input of the first controllably conductive device to provide a first impedance in series with the first control input; and a second variable drive circuit coupled in series electrical connection with the second control input of the second controllably conductive device to provide a second impedance in series with the second control input; wherein the first impedance of the first variable drive circuit is operable to change substantially only in response to a first temperature of the first controllably conductive device and the second impedance of the second variable drive circuit is operable to change substantially only in response to a second temperature of the second controllably conductive device.