Cordless telephone having power failure detection circuit
US5661780A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 1995 |
| Grant date | Aug 26, 1997 |
| Priority date | — |
| Expiry date | Nov 21, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02D30/70
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A cordless telephone can include a base unit including a cordless telephone circuit, a power source circuit and a resistor connected between a pair of power output terminals of the power source circuit, and a handset unit including a cordless telephone circuit, a secondary battery, a circuit connected between a charging terminal which receives power supply output from the power source circuit and a terminal of the secondary battery and consisting of a diode and a resistor connected in parallel to each other and a power break detection circuit. The secondary battery is usually charged by power supply from the power source circuit via the charging terminal and diode when the handset unit is placed in a cradle of the base unit, and electric power is supplied from the secondary battery to the cordless telephone circuit in the handset unit to operate in intermittent reception mode. When a break in power occurs at the base unit, the voltage at the charging terminal is dropped to a voltage level obtained by dividing the charged voltage at the secondary battery with two resistances which is lower than a reference voltage. Accordingly, the power break detection circuit outputs a power break…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.