| 摘要 |
PURPOSE:To reduce the characteristic deterioration with time by forming a current mirror circuit to a high voltage line to shunting the current, thereby reducing a stress onto a limiting diode. CONSTITUTION:The circuit is provided with current mirror circuits 1, 2 connected to a high voltage line Vp, a diode 3 connected to an input terminal of the current mirror circuits 1, 2 and to a ground line and making an output current flow when a voltage at the input terminal is a prescribed voltage or higher, and a means supplying the output current of the current mirror circuits 1, 2 to a power supply. That is, the current flowing to power supply VDD, GND is adjusted respectively by adjusting a ratio of two transistors(TRs) 1, 2 of the current mirror circuit, and the current flowing to the Zener diode 3 is decreased by dividing the current into the power supply and the GND. Thus, the stress to the limiter diode 3 is reduced and the characteristic deterioration is decreased. |
