Patent · US Expired

Voltage detecting circuit

US4922133A · kind A · utility

25Cited by
4References
10Claims
0Family size

Assignee

Inventors

Key dates

Filing dateJul 29, 1988
Grant dateMay 1, 1990
Priority date
Expiry dateJul 29, 2008

Classification

  • Technology area (CPC H)Electricity
  • CPC primaryH03K5/08
  • WIPO fieldBasic communication processes
  • WIPO sectorElectrical engineering

Abstract

A voltage detecting circuit comprising a voltage-input terminal for receiving a first voltage or a second voltage higher than the first voltage, switch means connected between the voltage-input terminal and a first node, and an inverter circuit having an input terminal coupled to the first node and an output terminal coupled to a second node. The switch circuit is turned on when the voltage at the voltage-input terminal is higher than a predetermined value which is between the higher than the first voltage and lower than the second voltage, and is turned off when the voltage at the voltage-input terminal is lower than the predetermined value. The inverter circuit includes a first transistor having a source-drain path coupled between a first power-source potential terminal and the second node, a current control section for maintaining a current flowing through the source-drain path of the first transistor at a predetermined value, and a second transistor having a source-drain path connected between the second node and a second power-source potential terminal and a gate coupled to the first node.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.