| 摘要 |
PROBLEM TO BE SOLVED: To contrive the enhancement of the accuracy of the detected value of a current in an output current detecting circuit and the enhancement of the freedom of the design of the circuit. SOLUTION: In an output circuit, which has a first MOS transistor 1 between an output nodal point 5 and a power supply 7, a second MOS transistor 2, which is controlled by the same control circuit as that of the transistor 1, is connected with the output nodal point 5 and moreover, a third MOS transistor 3, which is turned off when the transistor 1 is turned on, is provided between the transistor 2 and the power supply 7. As a potential in a connection nodal point 4 between the transistor 2 and the transistor 3 is in direct proportion to an output current, this potential is compared with a reference voltage Vr1. As this detected value of a current has no relation with the relative accuracy of the transistor characteristics of the transistors, the accuracy of the detected value is enhanced and as there is not also restrictions on the structure of an output current detecting circuit, the freedom of the design of the circuit is enhanced. |
