US 6,320,429 B1Granted

Integrated circuit having a comparator circuit including at least one differential amplifier

AssigneeFuji Electric Co., Ltd.

InventorYukio Yano

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Abstract

An integrated circuit including a comparator circuit and a vertical voltage control switch element formed on a single substrate. The comparator circuit including a differential amplifier circuit having a current mirror circuit M, a differential amplifier circuit D1 with two current paths L1 and L2, and an inverter INV. The output section of the current mirror circuit M is used as a constant current source for the differential amplifier circuit. The current mirror circuit M includes a load MOS transistor 1, a MOS transistor 2 constituting an input section, and a MOS transistor 10 constituting an output section. The current path L1 of the differential amplifier circuit D1 includes a load MOS transistor 11, an amplifying depletion type MOS transistor 13, and an input terminal in1. Similarly, the current path L2 includes a load MOS transistor 12, an amplifying depletion type MOS transistor 14, and an input terminal in2. The inverter INV is constructed with a load MOS transistor 3 and a switching transistor 4.

Claims18

Dependent claims

An integrated circuit for controlling the current supplied to a load, the integrated circuit comprising:

a substrate;
a comparator circuit, formed on said substrate, comprising:
a constant current source;
input means for inputting a reference voltage signal and an input voltage signal;
a differential amplifier including at least two parallel current paths, each including
a first depletion-type MOS transistor, and
a second depletion-type MOS transistor having a gate connected to said input means to receive one of said input voltage signal and said reference voltage signal, a drain connected to said first depletion-type MOS transistor, and a source connected to said constant current source;
and
output means, connected to one of said current paths, for outputting an output signal representative of the comparison of said input voltage signal and said reference voltage signal;
and
an insulated gate vertical switching transistor, formed on said substrate and connected to the load, for continuing or discontinuing the current supplied to the load in response to said output signal.

8 more elements

Dependencies are inferred from the claim text.