Voltage monitoring apparatus

Abstract

The present invention provides a voltage monitoring apparatus capable of stable operation even in a low-voltage region. The voltage monitoring apparatus (1) includes: an inner voltage generating portion (40), lowering an input voltage (VIN) to generate an inner voltage (Vreg); an input voltage monitoring portion (30), receiving a power supply from an output terminal of the inner voltage generating portion (40) to operate; a switch portion (50), disposed between an input terminal of the input voltage (VIN) and the output terminal of the inner voltage generating portion (40); and a switch driving portion (60), turning on the switch portion (50) when the input voltage (VIN) is lower than a threshold voltage (for example, Vy<Vref), and turning off the switch portion (50) when the input voltage (VIN) is higher than the threshold voltage (for example, Vy>Vref). Furthermore, the threshold voltage is preferably set as, for example, turning off the switch portion (50) upon the inner voltage generating portion (40) changing to a state capable of outputting the inner voltage (Vreg) that is at least higher than a minimum operating voltage of the input voltage monitoring portion (30).

Dependencies are inferred from the claim text.