| 摘要 |
PURPOSE:To obtain a constant low voltage circuit in the area of a small pattern by providing with a circuit to dicide the currrent amplification ratio beta of each MOSFET taking out the difference between threshold voltages of two N- MOSFETs and applying a load current to them from their terminals. CONSTITUTION:Both P-MOSFETs 21, 22 work in a saturated area and the gate potential is common: therefore, the ratio of the current flowing in each FET21, 22 are equal to that between the current amplification ratios betap1 and betap2. Also, the current of the FET21 and 23 are equal, and there is same relation between the current flowing in the FET22 and that in FET24. And there is some relation also between the current flowing in the FET24 and the potential of an output terminal 25. The potential of this terminal 25 is related with all of the FETs 2 1-24, and the threshold voltage VTNH is the higher, the smaller current is applied to the FETs 21, 23, and also the smaller is the current flowing in the FET22. Further, the lower is the threshold VTHL, the nearer to -Vss the potential of the FET25 is. Thus, on the terminal 25, a constant voltage VTNH-VTNL that has no relation with the voltage of the power supply can be obtained. |
