Title:
PIEZOELECTRIC TRANSFORMER DRIVE CIRCUIT
Document Type and Number:
WIPO Patent Application WO/2008/056435
Kind Code:
A1
Abstract:
Provided is a piezoelectric transformer drive circuit capable of reducing a switching
loss of a full bridge circuit which drives a piezoelectric transformer. The drive
circuit includes: a full-bridge circuit (1) formed by FFT (field effect transistors)
(Q1 to Q4); a drive circuit (2) for the full-bridge circuit; a filter circuit (3)
for converting the rectangular wave outputted from the full-bridge circuit
(1) into a sinusoidal wave; and one or more piezoelectric transformers (4) connected
to the filter circuit (3). Each of the piezoelectric transformers (4) has a secondary
terminal connected to a cold cathode tube (5) serving as a backlight. The filter
circuit (3) is connected to an inductance (L1) for adjusting the current phase
of the full-bridge load in parallel to the output of the full-bridge (1) or the
piezoelectric transformers (4). Since the load impedance of the full-bridge circuit
(1) becomes inductive and the output current phase of the full-bridge circuit
(1) becomes "a delayed phase", no penetrating current flows.
Inventors:
HAYASHI YUJI (JP)
MIZUTANI AKIRA (JP)
MIZUTANI AKIRA (JP)
Application Number:
PCT/JP2007/001157
Publication Date:
May 15, 2008
Filing Date:
October 24, 2007
Export Citation:
Assignee:
TAMURA SEISAKUSHO KK (JP)
HAYASHI YUJI (JP)
MIZUTANI AKIRA (JP)
HAYASHI YUJI (JP)
MIZUTANI AKIRA (JP)
International Classes:
H02M3/24; H05B41/24; H02M7/00
Foreign References:
| JP2002165444A | 2002-06-07 | |||
| JP2000312474A | 2000-11-07 | |||
| JP2006280120A | 2006-10-12 |
Attorney, Agent or Firm:
KIUCHI, Mitsuharu (Toranomon-Yoshiara Bldg. 1-6-13, Nishi-Shinbashi, Minato-k, Tokyo 03, JP)
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