US5118997A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual feedback control for a high-efficiency class-d power amplifier circuit
Assignee: General Electric Co
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Filing: 1991-08-16
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Granted: 1992-06-02
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Expires: 2011-08-16
Abstract
Abstract A dual feedback control system for a Class-D power circuit maximizes efficiency by controlling the magnitude and phase angle of the resonant load circuit using two separate feedback loops. The first feedback loop changes the value of a first variable capacitor in response to difference in magnitude between the actual load impedance and the desired load impedance. The second feedback loop changes the value of a second variable capacitor in response to the phase difference between the actual phase angle and the desired phase angle. In this way, the real and imaginary components of the load impedance are controlled so that the Class-D circuit is in tune, and hence efficiency is maximized, over a wide range of load impedances. The dual feedback control of the present invention may be advantageously employed in the ballast of an electrodeless HID lamp system.
Inventors
- 👤 Sayed-Amr A. El-Hamamsy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:57
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/26; H05B41/28; H05B41/2806; Y; Y02; Y02B; Y02B20/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
111 words
A dual feedback control system for a Class-D power amplifier circuit including a resonant circuit having a variable impedance, comprising: a phase control feedback loop, including phase detecting means for detecting the phase angle between the resonant circuit voltage and resonant circuit current, said phase control feedback loop varying the phase angle of the resonant circuit current to tune said resonant circuit under different load conditions; and an amplitude control feedback loop, including amplitude comparator means for comparing the amplitude of the resonant circuit impedance with a reference amplitude, said amplitude control feedback loop varying the amplitude of the resonant circuit current to tune said resonant circuit under different load conditions.
Claim 2
Dependent Claim
111 words
A dual feedback control system for a Class-D power amplifier circuit including a resonant circuit having a variable impedance, comprising: a phase control feedback loop, including phase detecting means for detecting the phase angle between the resonant circuit voltage and resonant circuit current, said phase control feedback loop varying the phase angle of the resonant circuit current to tune said resonant circuit under different load conditions; and an amplitude control feedback loop, including amplitude comparator means for comparing the amplitude of the resonant circuit impedance with a reference amplitude, said amplitude control feedback loop varying the amplitude of the resonant circuit current to tune said resonant circuit under different load conditions.
Claim 3
Dependent Claim
72 words
The dual feedback control system of claim 1 wherein: said resonant circuit comprises an inductance, a first variable capacitor coupled in parallel with said inductance, and a second variable capacitor coupled in series with the parallel combination of said inductance and said first variable capacitor; said amplitude control feedback loop varies the capacitance of said first variable capacitor; and said phase control feedback loop varies the capacitance of said second variable capacitor.
Claim 4
Dependent Claim
25 words
The dual feedback control system of claim 2 wherein said first and second variable capacitors each comprise piezoelectric actuating means for varying the capacitance thereof.
Claim 5
Dependent Claim
21 words
The dual feedback control system of claim 2 wherein said first and second variable capacitors each comprise liquid crystal variable capacitors.
Claim 6
Dependent Claim
157 words
A ballast for a high intensity discharge lamp of the type having an excitation coil situated about an arc tube for exciting an arc discharge in an ionizable fill contained in said arc tube, comprising: a Class-D power amplifier including two switching devices coupled in series in a half-bridge configuration and having an output resonant circuit coupled at the junction between said two switching devices; a phase control feedback loop, including phase detecting means for detecting the phase angle between the resonant circuit voltage and resonant circuit current, said phase control feedback loop varying the phase angle of the resonant circuit current to tune said resonant circuit under different load conditions; and an amplitude control feedback loop , including amplitude comparator means for comparing the amplitude of the resonant circuit impedance with a reference amplitude, said amplitude control feedback loop varying the amplitude of the resonant circuit current to tune said resonant circuit under different load conditions.
Claim 7
Dependent Claim
157 words
A ballast for a high intensity discharge lamp of the type having an excitation coil situated about an arc tube for exciting an arc discharge in an ionizable fill contained in said arc tube, comprising: a Class-D power amplifier including two switching devices coupled in series in a half-bridge configuration and having an output resonant circuit coupled at the junction between said two switching devices; a phase control feedback loop, including phase detecting means for detecting the phase angle between the resonant circuit voltage and resonant circuit current, said phase control feedback loop varying the phase angle of the resonant circuit current to tune said resonant circuit under different load conditions; and an amplitude control feedback loop , including amplitude comparator means for comparing the amplitude of the resonant circuit impedance with a reference amplitude, said amplitude control feedback loop varying the amplitude of the resonant circuit current to tune said resonant circuit under different load conditions.
Claim 8
Dependent Claim
71 words
The ballast of claim 5 wherein: said output resonant circuit includes the inductance of said excitation coil coupled in parallel with a first variable capacitance, the parallel combination of said inductance and said first variable capacitance being coupled in series with a second variable capacitance; amplitude control feedback loop varies the capacitance of said first variable capacitance; and said phase control feedback loop varies the capacitance of said second variable capacitance.
Claim 9
Dependent Claim
22 words
The ballast of claim 6 wherein said first and second variable capacitances each comprise piezoelectric actuating means for varying the capacitance thereof.
Claim 10
Dependent Claim
18 words
The ballast of claim 6 wherein said first and second variable capacitances each comprise liquid crystal variable capacitors.
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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) | 1995-06-02 | 1995-12-02 | 1996-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-02 | 1999-12-02 | 2000-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-02 | 2003-12-02 | 2004-06-02 | $7700.00 | Window Closed / Lapsed |