| 摘要 |
PROBLEM TO BE SOLVED: To provide a hysteresis circuit which is constituted of a small number of elements and breaks a circuit current (dark current) when no signal is inputted. SOLUTION: When the input voltage Vin of this hysteresis circuit is 0 V, all transistors Q11-Q14 are turned off and the output voltage Vc of the circuit becomes 0 V. In addition, the current flowing from a power supply line 14 to another power supply line 15 also becomes 0 (zero). When the input voltage Vin rises, the transistor Q12 is turned on and the voltage dividing ratio of a voltage dividing circuit 18 is decided depending upon resistors R12 and R13. When the transistor Q13 is turned on, the transistor Q14 is turned on due to the voltage drop of a resistor R16 and the output voltage Vc becomes VB. At the same time, the transistors Q11 and Q12 are respectively turned on and off, and the voltage dividing ratio of the voltage divider 18 is decided depending upon resistors R12, R13, and R14.
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