| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply circuit capable of reducing an element size by reducing the number of resistors, and supplying high-accurately and stably a constant current. SOLUTION: A constant current circuit includes: a pair of MOS transistors Q2, Q3 mutually constituting a current mirror; a current detection resistor (R4, R5) connected to a drain of one transistor Q2 in series; and a regulator circuit (constant voltage control part 2) controlling a drain current (I<SB>2D</SB>) of the transistor Q2 constantly based on an inter-terminal voltage of the current detection resistor. Thereby, the power supply circuit has a constitution where the number of the resistors is smaller than before. COPYRIGHT: (C)2011,JPO&INPIT |
