Patent ID: 6879115
Filing Date: 2005-04-12
Classification: H05B,Y02B

Abstract:
1. An integrated circuit for controlling a power supply circuit which delivers power to a load circuit that includes a fluorescent lamp, comprising: ballast control and drive circuitry that provides drive signals to the power supply circuit, that receives sense signals indicating operating conditions of at least one of the power supply circuit and the load circuit, and that responds to the sense signals by modifying the drive signals; and including adaptive zero-voltage-switching and minimum-current-switching (ZVMCS) circuitry, wherein said ZVMCS circuitry senses an output of said power supply circuit and in response thereto, controls said drive circuitry to maintain said power supply circuit under ZVMCS conditions; wherein the power supply circuit includes a half-bridge circuit with low and high side power devices, the drive signals including low side drive signals to control the low side power device and high side drive signals to control the high side power device; the ballast control and drive circuitry including a low side drive output for providing the low side drive signals to the low side power device and a high side drive output for providing the high side drive signals to the high side power device; and wherein said ZVMCS circuit senses an output voltage of said half-bridge circuit between said high side and low side power devices at a switching time of one of said power devices, and controls said drive signals so as to maintain said output voltage near or at zero at said switching time.