| 摘要 |
PURPOSE:To prevent switching loss by starting the generation of auxiliary control pulse at the end of main control pulse, sustaining the generation until the next generating time and ending the generation at the end of next pulse. CONSTITUTION:Main control pulse generating circuits 6-9 are controlled by an oscillator 14 and a phase control circuit 15 to generate first to fourth main control pulses which are fed to main switching elements TR4-TR4. In response to the trailing edge of the second main control pulse, a first auxiliary pulse generating circuit 10 generates an auxiliary control pulse to be fed to an auxiliary switching element SW1. In response to the trailing edge of the first main control pulse, a second auxiliary pulse generating circuit 11 generates an auxiliary control pulse to be fed to an auxiliary switching element SW2. In response to the railing edge of the fourth main control pulse, a third auxiliary control pulse generating circuit 12 generates and auxiliary control pulse to be fed to an auxiliary switching element SW3. In response to the trailing edge of the third main control pulse, a fourth auxiliary control pulse generating circuit 13 generates an auxiliary control pulse to be fed to an auxiliary switching element SW4. This circuitry allows zero volt switching thus reducing power loss. |
