| 摘要 |
PURPOSE:To hold voltage in a constant state even if supply voltage is varied, by constituting two transistors TR so that the resistance values are different in supply voltage dependent property, and dividing the resistance. CONSTITUTION:An electric power source Vcc is connected to a series circuit of resistances R1, R2 and TRs Q4, Q5, a connection point I of the resistances R1, R2 is connected to a gate of the TRQ4, also voltage Vcc is connected to a gate of the TRQ5, and output voltage VR is outputted from a connection point II of the TRs Q4, Q5. Voltage of the connection point I is made Va, and when voltage of the electric power source Vcc is varied by DELTAV, the voltage Va is varied by alpha.DELTAV (0<alpha<1). alpha is given by R2/(R1+R2). A resistance portion of the TRQ4 and that of the TRQ5 are varied by following alpha.DELTAV and DELTAV, respectively. Accordingly, when supply voltage has been varied high, a resistance value decreased portion of the TR Q5> a resistance value decreased portion of the TRQ4 is caused in order that voltage VR of the point II is held in a constant state. When supply voltage has been varied low, a resistance value increased portion of the TRQ5> a resistance value increased portion of the TRQ4 is caused, and voltage VR is held in a constant state. |
