| 摘要 |
PURPOSE:To simplify the circuit constitution, by giving an output detecting an alternating voltage signal on which a DC signal is superimposed in the current mode to an input terminal connected with a resistor and a DC blocking capacitor and inputting the signal at the capacitor to a feedback amplifier. CONSTITUTION:A DC and an AC signal are superimposed in a balanced voltage signal source 1 of a balanced/unbalanced signal converting circuit A. A voltage of the signal source 1 is converted into a current signal with a resistor (R)0 and current mirror circuits 2, 3 and given to a current mirror circuit 4. Only the DC component I of the output current of the circuit 4 is converted into a DC voltage at an R1, an AV component (i) is inputted to an inverting input of an operational amplifier 9 via a DC block capacitor C1 and the current/voltage conversion is attained with an R4 constituting the feedback circuit. Thus, the design of the AC current voltage converting circuit is attained independently of the design of a DC current voltage converting circuit, and malfunction of the DC loop detection due to the AC signal is prevented. Thus, the DC current voltage converting circuit and the AC current voltage converting circuit are incorporated in this way. |
