| 摘要 |
PURPOSE:To attain power supply by providing the 1st and 2nd FFs supplying power to a load circuit at set state and controlling the state of the FFs in response to the state of a power switch and an output state of an oscillating signal from the load circuit. CONSTITUTION:When a power switch 1 is depressed, a power supply switch state signal 4 of an output of an inverter 3 goes to high. The 1st FF7 is set at the leading of the high signal via a gate 5, a Q output 11 goes to high and a Q' output goes to low. On the other hand, the 2nd FF8 keeps the preceding state. A Q output of the 1st FF7 is a power supply output 14 to the load circuit 15 via a gate 13. When the power supply is started to the load circuit 15, an oscillating signal output 20 is outputted from an oscillating circuit 16 and applied to gates 21, 22. An output of the gate 22 is high continuously when a hand is detached from the power switch 1 to be OFF, while an output of an inverter 24 is low continuously, then the 3rd FF23 is triggered to be set, and its output Q goes to high. Thus, the 2nd FF8 is set. |
