Overcurrent detecting circuit and reference voltage generating circuit

Abstract

The invention relates to an overcurrent detecting circuit which may includes a reference load (M1 as MOSFET) through which a reference current flows, generating a reference voltage corresonding to the reference current. A differential amplifier section (M11, M12, M13, M14) is included to amplify the difference in the potentials of two inputs. A bias current supplied by a constant current source (Ib) flows through the differential amplifier section. At least part of a bias current flows to the reference load. A detection voltage, corresponding to a current subject to overcurrent detection, is inputted to one of the two inputs of the differential amplifier section while the drain electrode of M10 entries to one of the two inputs potentials of the differential amplifier section. Thus, the invention can reduce the total current consumed by an electronic circuit.

Description

technical field [0001] The present invention relates to techniques for reducing power consumption in electronic circuits. Background technique [0002] Even in electronic circuits such as DC-DC converters, such as circuits used in portable devices, it is also urgently required to reduce power consumption. [0003] Circuits of conventional overcurrent detection circuits used in DC-DC converters and the like are shown in Figure 4 . However, the circuit shown in this figure is the circuit listed in Patent Document 1 as prior art. [0004] exist Figure 4 Among them, both M0 and M1 are n-channel MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). Here, M0 is the main FET (Field Effect Transistor) of the output stage of the DC-DC converter, which drives the load ZL. The drain current Id0 of M0 flows from the power supply line VD to the ground line (reference potential) via the driven load ZL and M0. Further, M1 is a FET (Field Effect Transistor) functioning as a re...

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Problems solved by technology

[0017] In addition, in order to obtain sufficient response speed, perform Figure 4 The comparator COMP, which compares the drain potential Vd0 and Vd1 in the circuit, must also have a certain degree of power consumption (for example, 50μA)

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