Patent attributes
A voltage detection circuit for accurately detecting a voltage that is unaffected by fluctuation due to variations in transistor characteristics and threshold voltage. The voltage detection circuit includes a reference current generating section and a detecting section. The reference current generating section includes a voltage-controlled current source that includes a control terminal, a reference terminal and an output terminal. The reference current generating section generates an output current that serves as a reference current and output to a current mirroring circuit. The detecting section includes a number of voltage-controlled current sources each with the same configuration as the voltage-controlled current sources in the current generating section. A potential to be detected is input into the detecting section. A target potential is calculated as the set potential multiplied by the number of voltage-controlled current sources in the detecting section. When the absolute value of the potential to be detected equals the target potential, the currents in each of the voltage-controlled current sources in the detecting section is set equal to the set potential. Due to the equivalent configurations of the voltage-controlled current sources, the current flowing in the reference current generating section is balanced with, and becomes equal to the current in the detecting section. The detection is made by current comparison between the reference current output from the reference current generating section and the detection current flowing in the detecting section.
