US3629616A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-efficiency modulation circuit for switching-mode audio amplifier
Assignee: Raytheon Co
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Filing: 1969-07-01
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Granted: 1971-12-21
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Expires: 1989-07-01
Abstract
Abstract A circuit for efficiently coupling an amplified audio signal to a transducer is disclosed. In the form herein described, two 180* out-of-phase audio signals are respectively applied to first and second comparators which compare the audio signals with a reference signal to produce two pulse-width-modulated signals. The latter signals are applied to switching semiconductors connected in the two arms of a bridge which includes the transducer.
Inventors
- 👤 Neil Edward Walker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:21
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/20; H03F3/21; H03F3/217
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
254 words
A signal circuit for supplying an amplified input audio signal to an output transducer, said circuit comprising an input terminal, means operatively connected to said input terminal for producing from said input audio signal first and second phasedisplaced signals, means coupled to said phase-displaced signal producing means for producing first and second control pulse signals having pulse widths respectively corresponding to the relative amplitudes of said first and second phase-displaced signals, output means includIng a balanced bridge coupled to said control-signal-producing means and having first, second, third and fourth arms, a pair of junction points being defined between said first and second arms and said third and fourth arms respectively, for the connection of said transducer therebetween, first, second, third and fourth switching means each having a control terminal connected in said first, second, third and fourth arms respectively, means for applying said first and second control signals to the control terminals of said first and third switching means respectively, and means for respectively coupling said second and fourth switching means to said first and third switching means for respectively rendering said second and fourth switching means unconductive when said first and third switching means are rendered conductive in response to said first and second control signals respectively, and for rendering said second and fourth switching means conductive when said first and third switching means are rendered nonconductive in response to said first and second control signals respectively, whereby an output signal proportional to said input audio signal is developed across said junction points.
Claim 2
Dependent Claim
254 words
A signal circuit for supplying an amplified input audio signal to an output transducer, said circuit comprising an input terminal, means operatively connected to said input terminal for producing from said input audio signal first and second phasedisplaced signals, means coupled to said phase-displaced signal producing means for producing first and second control pulse signals having pulse widths respectively corresponding to the relative amplitudes of said first and second phase-displaced signals, output means includIng a balanced bridge coupled to said control-signal-producing means and having first, second, third and fourth arms, a pair of junction points being defined between said first and second arms and said third and fourth arms respectively, for the connection of said transducer therebetween, first, second, third and fourth switching means each having a control terminal connected in said first, second, third and fourth arms respectively, means for applying said first and second control signals to the control terminals of said first and third switching means respectively, and means for respectively coupling said second and fourth switching means to said first and third switching means for respectively rendering said second and fourth switching means unconductive when said first and third switching means are rendered conductive in response to said first and second control signals respectively, and for rendering said second and fourth switching means conductive when said first and third switching means are rendered nonconductive in response to said first and second control signals respectively, whereby an output signal proportional to said input audio signal is developed across said junction points.
Claim 3
Dependent Claim
55 words
The circuit of claim 1, further comprising first and second constant-current means operatively connected to the control terminals of said first and second switching means and said third and fourth switching means respectively, for increasing the rate at which said first, second, third and fourth switching means change between their respective conductive and nonconductive states.
Claim 4
Dependent Claim
114 words
The circuit of claim 2, in which said first, second, third and fourth switching means respectively comprise first, second, third and fourth semiconductor devices each comprising one of said control terminals and an output circuit, said output circuits of said first and second semiconductor devices and of said third and fourth semiconductor devices being respectively connected to one another at said junction points, said constant-current means comprising fifth and sixth semiconductor devices each having an output circuit operatively connected to the control terminals of said first, second, third and fourth semiconductor devices respectively, and further comprising means for establishing a substantially constant-bias potential at the control terminal of said fifth and sixth semiconductor devices.
Claim 5
Dependent Claim
84 words
The circuit of claim 3, in which said first, second, third and fourth semiconductor devices are all of one conductivity type, said bridge further comprising seventh, eighth, ninth and tenth semiconductor devices of an opposite conductivity type than said first, second, third and fourth semiconductor devices and having output circuits operatively connected to the control terminals of said first, second, third and fourth semiconductor devices respectively, and defining means for controlling the conductivity states of said first, second, third and fourth semiconductor devices respectively.
Claim 6
Dependent Claim
45 words
The circuit of claim 4, in which the output circuit of said fifth and sixth semiconductor devices are in operative circuit relation with the output circuits of said seventh and ninth semiconductor devices and with the input circuits of said eighth and tenth semiconductor devices.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |