Circuit for inhibiting inrush current

Abstract

Abstract PURPOSE:To ease the inrush current when a power source is turned ON by connecting a time constant circuit in parallel with a sensing amplifier which senses the output, operating said time constant circuit when the power source is turned ON, and obtaining a reactive state under a steady state. CONSTITUTION:Zero crossing of an AC power source 1 is sensed by a zero cross sensor 2, and zero crossing pulses are generated. Then a saw tooth wave is generated from a saw tooth wave generator 3. In the meantime, an output is supplied from the sensing ampifier 7 which senses a power source imput voltage 9 from a phase control circuit. Both signals are compared in a comparator 4, igniting pulses are generated and amplified in a pulse amplifier 5, thereby obtaining an output 6. The rise of the power source voltage immediately after the turn ON of the AC power source is made gentle (t=1-t1) by the time constant circuit 8 which is connected in parallel with the sensing amplifier 7, and the time constant circuit becomes reactive (t=t1-t2) when the steady state is obtained (t=t1). Thus the inrush current can be effectively inhibited only when the power source is turned ON.

Inventors

• 👤 Katsuhiko Higashiyama
• 👤 Mikio Maeda
• 👤 Masahiro Kosaka

Bibliographic Details