US5566064A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High efficiency supply for electroluminescent panels
Assignee: Apple Inc
•
Filing: 1995-05-26
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Granted: 1996-10-15
•
Expires: 2015-05-26
Abstract
Abstract Apparatus for operating electroluminescent panels. An electroluminescent panel is driven by a voltage source feeding a modified bridge driven by a pulse width modulated signal. By using a pulse frequency above the range of human hearing and a modulating signal that is a sine wave of the proper frequency for operating the panel, a sine wave is generated across the panel without requiring bulky low frequency magnetic components.
Inventors
- 👤 David S. Schoenwald
- 👤 Charles O. Forge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:46
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/4807; H02M7/53; H02M7/537; H02M7/538; H05; H05B; H05B44/00; Y; Y02; Y02B; Y02B20/00; Y02B20/30
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
175 words
Apparatus for operating an electroluminescent panel comprising: a DC source having positive and negative terminals; first and second capacitors connected in series between the positive and negative terminals of the DC source forming a voltage divider; a first output terminal for the electroluminescent panel connected to the junction of the first and second capacitors; a transformer having first and second windings, each of the first and second windings having a start and an end, the start of the first winding connected to the positive terminal of the DC source and the start of the second winding connected to the negative terminal of the DC source; first and second series connected switches, the first switch connected to the end of the first transformer winding and the second switch connected to the end of the second transformer winding; a second output terminal for the electroluminescent panel connected to the junction of the first and second switches; and switch driving means for driving the first and second switches in complementary fashion with a pulse width modulated switching signal.
Claim 2
Dependent Claim
175 words
Apparatus for operating an electroluminescent panel comprising: a DC source having positive and negative terminals; first and second capacitors connected in series between the positive and negative terminals of the DC source forming a voltage divider; a first output terminal for the electroluminescent panel connected to the junction of the first and second capacitors; a transformer having first and second windings, each of the first and second windings having a start and an end, the start of the first winding connected to the positive terminal of the DC source and the start of the second winding connected to the negative terminal of the DC source; first and second series connected switches, the first switch connected to the end of the first transformer winding and the second switch connected to the end of the second transformer winding; a second output terminal for the electroluminescent panel connected to the junction of the first and second switches; and switch driving means for driving the first and second switches in complementary fashion with a pulse width modulated switching signal.
Claim 3
Dependent Claim
14 words
The apparatus of claim 1 where the second output terminal is connected to ground.
Claim 4
Dependent Claim
37 words
The apparatus of claim 1 where the pulse width modulated switching signal has a pulse rate above 1,000 cycles per second and a sine wave modulating signal in the range of 60 to 1000 cycles per second.
Claim 5
Dependent Claim
25 words
The apparatus of claim 2 where the switch driving means further comprises a comparator fed by a sine wave source and a triangle wave source.
Claim 6
Dependent Claim
18 words
The apparatus of claim 4 where the frequency of the triangle wave is above 1,000 cycles per second.
Claim 7
Dependent Claim
23 words
The apparatus of claim 4 where the frequency of the sine wave is in the range of 60 to 1000 cycles per second.
Claim 8
Dependent Claim
13 words
The apparatus of claim 1 where the DC source is a voltage source.
Claim 9
Dependent Claim
17 words
The apparatus of claim 1 where the DC source is a boost mode DC to DC converter.
Claim 10
Dependent Claim
16 words
The apparatus of claim 1 where the DC source is a flyback DC to DC converter.
Claim 11
Dependent Claim
29 words
The apparatus of claim 1 further including control means for adjusting the voltage of the DC source based on sensing the voltage across the first and second output terminals.
Claim 12
Dependent Claim
30 words
The apparatus of claim 1 further including control means for adjusting the voltage of the DC source based on sensing the current flowing between the first and second output terminals.
Claim 13
Dependent Claim
157 words
Apparatus for operating an electroluminescent panel comprising: a first output terminal for connecting the electroluminescent panel; first and second DC sources, the negative end of the first DC source and the positive end of the second DC source both connected to the first output terminal; a second output terminal for connecting the electroluminescent panel; an inductor having first and second leads, the first lead of the inductor connected to the second output terminal; switching means connected to the second lead of the inductor, the switching means having a first position and a second position, in the first position the switching means connecting the second lead of the inductor to the positive end of the first DC source, and in the second position the switching means connecting the second lead of the inductor to the negative end of the second DC source; and switch driving means for driving the switching means with a pulse width modulated switching signal.
Claim 14
Dependent Claim
157 words
Apparatus for operating an electroluminescent panel comprising: a first output terminal for connecting the electroluminescent panel; first and second DC sources, the negative end of the first DC source and the positive end of the second DC source both connected to the first output terminal; a second output terminal for connecting the electroluminescent panel; an inductor having first and second leads, the first lead of the inductor connected to the second output terminal; switching means connected to the second lead of the inductor, the switching means having a first position and a second position, in the first position the switching means connecting the second lead of the inductor to the positive end of the first DC source, and in the second position the switching means connecting the second lead of the inductor to the negative end of the second DC source; and switch driving means for driving the switching means with a pulse width modulated switching signal.
Claim 15
Dependent Claim
37 words
The apparatus of claim 12 where the pulse width modulated switching signal has a pulse rate above 1,000 cycles per second and a sine wave modulating signal in the range of 60 to 1000 cycles per second.
Claim 16
Dependent Claim
25 words
The apparatus of claim 12 where the switch driving means further comprises a comparator fed by a sine wave source and a triangle wave source.
Claim 17
Dependent Claim
18 words
The apparatus of claim 12 where the frequency of the triangle wave is above 1,000 cycles per second.
Claim 18
Dependent Claim
23 words
The apparatus of claim 12 where the frequency of the sine wave is in the range of 60 to 1000 cycles per second.
Claim 19
Dependent Claim
29 words
The apparatus of claim 12 further including control means for adjusting the voltage of the DC source based on sensing the voltage across the first and second output terminals.
Claim 20
Dependent Claim
30 words
The apparatus of claim 12 further including control means for adjusting the voltage of the DC source based on sensing the current flowing between the first and second output terminals.
Claim 21
Dependent Claim
159 words
Apparatus for operating an electroluminescent panel comprising: a DC source having positive and negative terminals; a first output terminal for connecting the electroluminescent panel; a voltage divider connected to the positive and negative terminals of the DC source for providing half the source voltage at the first output terminal; a second output terminal for connecting the electroluminescent panel; an inductor having first and second leads, the first lead of the inductor connected to the second output terminal; switching means connected to the second lead of the inductor, the switching means having a first position and a second position, in the first position the switching means connecting the second lead of the inductor to the positive end of the DC source, and in the second position the switching means connecting the second lead of the inductor to the negative end of the DC source; and switch driving means for driving the switching means with a pulse width modulated switching signal.
Claim 22
Dependent Claim
159 words
Apparatus for operating an electroluminescent panel comprising: a DC source having positive and negative terminals; a first output terminal for connecting the electroluminescent panel; a voltage divider connected to the positive and negative terminals of the DC source for providing half the source voltage at the first output terminal; a second output terminal for connecting the electroluminescent panel; an inductor having first and second leads, the first lead of the inductor connected to the second output terminal; switching means connected to the second lead of the inductor, the switching means having a first position and a second position, in the first position the switching means connecting the second lead of the inductor to the positive end of the DC source, and in the second position the switching means connecting the second lead of the inductor to the negative end of the DC source; and switch driving means for driving the switching means with a pulse width modulated switching signal.
Claim 23
Dependent Claim
14 words
The apparatus of claim 19 where the voltage divider comprises two capacitors in series.
Claim 24
Dependent Claim
37 words
The apparatus of claim 19 where the pulse width modulated switching signal has a pulse rate above 15,000 cycles per second and a sine wave modulating signal in the range of 60 to 1000 cycles per second.
Claim 25
Dependent Claim
25 words
The apparatus of claim 19 where the switch driving means further comprises a comparator fed by a sine wave source and a triangle wave source.
Claim 26
Dependent Claim
18 words
The apparatus of claim 22 where the frequency of the triangle wave is above 15,000 cycles per second.
Claim 27
Dependent Claim
23 words
The apparatus of claim 22 where the frequency of the sine wave is in the range of 60 to 1000 cycles per second.
Claim 28
Dependent Claim
17 words
The apparatus of claim 19 where the DC source is a boost mode DC to DC converter.
Claim 29
Dependent Claim
16 words
The apparatus of claim 19 where the DC source is a flyback DC to DC converter.
Claim 30
Dependent Claim
29 words
The apparatus of claim 19 further including control means for adjusting the voltage of the DC source based on sensing the voltage across the first and second output terminals.
Claim 31
Dependent Claim
30 words
The apparatus of claim 19 further including control means for adjusting the voltage of the DC source based on sensing the current flowing between the first and second output terminals.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-10-15 | 2000-04-15 | 2000-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-10-15 | 2004-04-15 | 2004-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-10-15 | 2008-04-15 | 2008-10-15 | $7700.00 | Window Closed / Lapsed |