Driving circuit of a piezo-ceramic transformer capable of controlling an input voltage and a dimming control method thereof
US6331748A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 21, 2000 |
| Grant date | Dec 18, 2001 |
| Priority date | — |
| Expiry date | Apr 21, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10N30/804
Abstract
A fixed frequency driving circuit of a piezo-ceramic transformer capable of controlling an input voltage. The driving circuit includes a lamp; a PCT(Piezo-Ceramic Transformer) for driving the lamp; a PCT driving circuit for driving the PCT; a voltage doubler rectifier for rectifying an output voltage; a summing & error amplifying circuit for outputting by summing a dimming voltage and the output voltage; a charge pump circuit for maintaining zero voltage switching and reducing the switching loss; a temperature compensated VCO for compensating the temperature characteristics of PCT, and impact, etc. in the neighborhood; a phase detector for comparing the phase of the input and output signal of the PCT; a modulator capable of continuously obtaining an amplitude of a first harmonic frequency component when the input voltage is changed from Vmin to Vmax by controlling a duty ratio provided to a driver connected to the PCT according to the output signals of the phase detector and the summing & error amplifier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.