Constant power supply unit of electric heating apparatus
US4975630A · kind A · utility
Inventor
Key dates
| Filing date | Mar 8, 1989 |
| Grant date | Dec 4, 1990 |
| Priority date | — |
| Expiry date | Mar 8, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M5/2573
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A constant power supply unit of an electric heating apparatus is disclosed. A voltage sensing circuit generates a DC reference signal corresponding to the nominal value of an AC supply voltage. A timing pulse generator generates a rectangular waveform signal during one of every four cycles. A trigger generator generates a trigger signal at zero-cross points determined by the combination of outputs of a voltage sensing circuit and the timing pulse generator. A power control circuit controls the input power to the electric heating apparatus by the trigger signal, thereby allowing a constant power supply to the electric heating apparatus regardless of the nominal value of the AC supply voltage which may be either 220 volts or 100 volts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.