| 摘要 |
PURPOSE:To obtain a voltage generation circuit having no oscillation, by performing a control to turn on a MOSFET having a low threshold voltage compulsorily, and to detect the voltage of the MOSFET having a high threshold voltage. CONSTITUTION:A start-up circuit 1 detects the voltage generated at a MOSFETQ6 whose threshold value is set higher than that of a MOSFETQ5, at a detection circuit 2, and operates the MOSFETs Q5 and Q6 to be turned on compulsorily at a power supply applying time based on the above result. In a constant current circuit 3, a current mirror circuit consisting of P- MOSFETs Q7 and Q8 is provided at a power source terminal Vdd side, and also, a ratio type CMOS inverter circuit consisting of a P-MOSFETQ9 and an N-MOSFETQ10 are coupled to limit a current flow on the MOSFETQ8 smaller, and it is constituted so that a current equivalent to the one permitting to flow on the MOSFETQ8 is permitted to flow on the MOSFETQ7.
|
