| 摘要 |
PURPOSE:To reduce the leak of the error current by controlling the constant current source by the output of the detector for the unbalanced current. CONSTITUTION:When the driving pulse is applied to current switching type switch circuit 3 and 4 with transistor 5 and 7 made to conduct, the current flows to diodes 10-13 via constant current source 1 and 2. And diode bridge 9 openes to secure the conducting state between input terminal 14 and output terminal 15. Then transistor 6 and 8 are made to conduct by the driving pulse, and thus diodes 10-13 are biased reversely via resistance 16 and 17. As a result, no current flows to bridge 9 with the nonconducting state secured between terminal 14 and 15. During such operation, the error current is caused if source 1 and 2 are under an unbalanced state to be leaked outside through terminal 14 and 15. To prevent this, the error current is integrated by error current detector 18 comprising differential amplifier 19 and capacitor 20 to be converted into the voltage level which is supplied to variable constant current source 2. |
