| 摘要 |
PURPOSE:To reduce power consumption, by controlling the resonance operation by the switching system to form a saw tooth wave signal. CONSTITUTION:When a switching pulse Ps is supplied to a switching transistor Q, a resonance current loop of a resonance circuit 20 is formed, and electric charge stored in a capacitor C is discharged through a coil L, and therefore, a resonance current iL is flowed to the coil L. A width Tb of this resonance current iL is determined by a resonance frequency fc; and if a pulse width Ta of the switching pulse Ps is longer than the width Tb, concretely, Tb<=Ta<=2Tb is true, the negative half cycle of the resonance current iL is stopped by a diode d, and therefore, the negative resonance current is not flowed to the capacitor C. Consequently, the resonance current iL becomes a positive pulse current. In case that a positive pulse voltage is flowed to the resonance circuit 20, a resonance voltage Vc of saw tooth waves is generated in both ends of the capacitor C. |
