| 摘要 |
PURPOSE:To obtain a generating circuit of reference voltage having high temperature stability by using two MOS elements connected in parallel to each other that have the same conduction type, the same threshold voltage and same size as the 1st or 2nd MOS element which extracts the reference voltage and a bias circuit to constitute a constant current source. CONSTITUTION:A series circuit of a depression type NMOS element 11 and a resistance 13 is connected in parallel to a series circuit of an enhancement type NMOS element 12 and a resistance 14. An end of this series circuit is connected to a battery voltage terminal 2; while the other end is grounded via a parallel circuit of MOS elements 31 and 32. The voltages at junctions between elements 11/12 and resistances 13/14 are connected to an operational amplifier 21. The output of the amplifier 21 is fed back to the gate of the element 12. The elements 31 and 32 have the same conduction type as the elements 11 and 12 together with the same threshold voltage and same size respectively. A constant voltage source 30 supplies the bias voltage to the elements 31 and 32. The gate of the element 11 is grounded. Thus it is possible to obtain the reference voltage having high temperature stability at an output terminal 1 by controlling the size ratio between elements 11 and 12 and the temperature coefficient of the bias voltage. |
