MAXIMUM VOLTAGE DETECTION CIRCUIT AND MINIMUM VOLTAGE DETECTION CIRCUIT

摘要

A maximum voltage detection circuit and a minimum voltage detection circuit are provided to detect a maximum voltage with high accuracy by applying an input voltage to a gate of an NMOS transistor. A plurality of first NMOS transistors(11-1n) are connected between a power potential and a first node and have the same electrical property which is controlled by an input voltage assigned to each gate. A second NMOS transistor(4) has the same electrical property as the first NMOS transistors and is connected between the power potential and a second node. A conducting state of the second NMOS transistor is controlled by an output voltage assigned to a gate. First and second constant current circuits(2,5) are connected between the first and second nodes and grounding potential in order to apply the constant current. An operational amplifier(3) includes a non-inverted input terminal and an inverted input terminal connected with the first and second nodes and an output terminal for outputting an output voltage.