Power failure indicator
US4703410A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 7, 1986 |
| Grant date | Oct 27, 1987 |
| Priority date | — |
| Expiry date | Apr 7, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/24
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A power failure indicator circuit for a pulse width modulated power supply compares the averaged voltage of the pulse width modulated signal to an input reference voltage to determine if power failure of the supply will occur. The reference voltage corresponds to a predetermined proportion of the maximum average voltage of the pulse width modulated signal. In a preferred embodiment, the pulse width modulated signal is inverted and filtered to generate an averaged signal corresponding to the DC input voltage to the modulator within the pulse width modulated power supply. A comparator compares the averaged signal voltage to the reference voltage to determine if the averaged signal voltage level has fallen below the reference voltage level. If the averaged signal voltage level does drop below the reference voltage level, the comparator generates a signal warning of power failure of the power supply.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.