| 摘要 |
PURPOSE:To eliminate an offset voltage and to improve a light load characteristic by applying time division multiplication to two signals proportionate to the load voltage of a feeder and a consumed current and adding the difference voltage of a positive and a negative voltages to an integrating circuit connected to a multiplier circuit. CONSTITUTION:Signals ev, ei proportional to the load voltage of a feeder and the consumed current enter a multiplier circuit 13 from an auxiliary transformer 11 and an auxiliary current transformer 12. The circuit 13 is a pulse width modu lating circuit and forms the multiplied voltage of signals ev, ei by time division multiplication. An integrating circuit 14 integrates this multiplied voltage and converts to a pulse whose frequency proportional to the multiplied voltage. The output pulse of the circuit 14 is integrated by an offset voltage extracting circuit 17 and a signal voltage coresponding to an offset voltage is taken out, and a negative feedback signal is fed to the input terminal of the circuit 14. At the same time, positive and negative voltages of a power source 18 is compared, and the differential voltage is taken out and added to the input of the circuit 14. Thus, unbalance of the positive and negative voltages and the offset voltage can be erased. |
