Patent · US Active

Minimum voltage detector circuit

US11178742B1 · kind B1 · utility

0Cited by

3References

20Claims

0Family size

Assignee

Apple Inc. · US

Inventors

Angelo Bassi · Munich, DE
Bogdan-Eugen Matei · Westerndorf, DE

Key dates

Filing date	Jul 15, 2020
Grant date	Nov 16, 2021
Priority date	—
Expiry date	Jul 15, 2040

Classification

Technology area (CPC H)Electricity
CPC primaryH05B47/24
WIPO fieldElectrical machinery, apparatus, energy
WIPO sectorElectrical engineering

Abstract

A minimum voltage detector circuit is disclosed. The circuit includes a plurality of LED strings each having a plurality of series-coupled LEDs. The minimum voltage detector circuit is configured to detect a minimum voltage from among the plurality of LED strings, and also to perform open/short detection among the plurality of LED strings. The minimum voltage detector circuit includes a plurality of voltage comparators and correspondingly coupled replica circuits. Each of the voltage comparators includes an amplifier having a first input coupled to a cathode of a last LED of one of the plurality of LED strings, an output, and a second input coupled to the output. Each voltage comparator further includes a replica circuit coupled to the amplifier. The replica circuit is configured to maintain an output transistor of the amplifier in an active state when the amplifier is in an unbalanced state.

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