| 摘要 |
<p>PURPOSE:To detect a line current with high accuracy even if the line current is small by providing a 1st and a 2nd voltage current converting circuit on one side of a current detecting means, generating an output current corresponding to the difference between a reference voltage and a control voltage which are applied to the reference terminals and control terminals of the converting circuits, and supplying the output current to both terminals of the other current detecting resistance through 1st and 2nd load resistances. CONSTITUTION:The 1st and the 2nd voltage current converting means 5 and 7 are provided to a reference voltage source which generates the specific reference voltage Er and one side of a current detecting means connected to a line in series. Then those voltage current converting means generate output currents corresponding to voltage differences between the reference voltage Er and the sum of a voltage across one current detecting means and reference voltage and those currents are supplied to both ends of the other current detecting means through the load resistances RL1 and RL2 to detect the line current. Therefore, even if the current flowing through the line becomes opposite in flow direction, the circuit operates and even if the current is zero, the line current is securely and accurately detected.</p> |
