PURPOSE:To decrease power consumption by providing a feedback means from a current supply circuit to a control circuit and bringing the control circuit in non-operation state when the current supply circuit is brought into the non- operating state so as to zero substantially the current consumption at non- operation when no current is given to a load. CONSTITUTION:When a high level is fed to a control terminal 1 or the terminal 1 is opened and Q1, Q2 are turned off, then no base current flows, then Q3 and Q4 are brought into the OFF state. When a high level is fed to the control terminal 1, a Q5 is turned on and the control circuit brings the constant current circuit to the non-operating state. When the constant current circuit is in non- operating state, a Q6 is in OFF state, and then the Q5 is turned off. That is, when the constant current circuit is in the non-operating state, the control circuit is brought into the non-operating state. thus, all transistors of the control circuit and constant current circuit are turned off to be stable thereby zeroing substantially the current lowing from the power supply to ground.
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