| 摘要 |
PURPOSE: To select control over the supply and cutoff of a power source or control over its output voltage by providing a means which forcibly turns ON a transistor(TR) and making its output ineffective, and providing a means which forcibly turning OFF a TR. CONSTITUTION: When an H signal is inputted to an ON/OFF terminal 7, the base voltages of TRs Q5 and Q6 go up to an H level and the TRs Q5 and Q6 turn ON. Therefore, the base voltage of a TR Q3 goes down to an L level and the TR Q3 turns OFF. Further, the base voltage of a TR Q2 also falls to the L level and the TR Q2 turns OFF. Consequently, a resistor R1 has no voltage drop and a voltage control TR Q1 is held OFF, so that an output voltage to a load becomes 0V. Then when an L signal is inputted to the ON/OFF terminal 7 and an H signal is inputted to a switching terminal 6, the TR Q3 turns ON and the voltage control TR Q1 is always in the ON state through similar operation. The output to the load, therefore, becomes 12V at all times. |
