US3747005A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic biased controlled amplifier
Assignee: Motorola Solutions Inc
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Filing: 1971-02-01
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Granted: 1973-07-17
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Expires: 1991-02-01
Abstract
Abstract An audio power amplifier comprising a transistor operated as an emitter follower which is quiescently biased so that the DC current through the output speaker is small. A feedback circuit connected between the output and the control electrode of the transistor compares the magnitude of the output peak voltage with the magnitude of the bias potential on the control electrode. When the peak output voltage exceeds the magnitude of the bias potential the feedback circuit increases the control bias potential to raise the operating point of the transistor. Where the magnitude of the peak voltage of the output does not exceed the magnitude of the bias potential, there is no feedback and the bias potential is maintained to keep the transistor at its quiescent operating point.
Inventors
- 👤 R Freimark
- 👤 O Nilssen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:55
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/181; H03F3/183
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
163 words
An automatic biased controlled amplifier circuit producing AC output signals in response to AC input signals, said amplifier comprising amplifying means including an electron control device having control and output electrodes, first circuit means coupling the AC input signal to said electron control device, bias circuit means connecting a predetermined bias voltage to the control electrode of said electron control device for biasing the same substantially to its quiescent operating point, feedback circuit means including a diode and a capacitor connected between the output and control electrodes of said electron control device, said diode connected between the output electrode of said electron control device and said capacitor to charge said capacitor by an output signal of one polarity from said electron control device exceeding said predetermined bias voltage to raise the operating point of said electron control device from said substantially quiescent condition to permit the passing of the AC input signal of a polarity opposite said one polarity substantially free of distortion.
Claim 2
Dependent Claim
163 words
An automatic biased controlled amplifier circuit producing AC output signals in response to AC input signals, said amplifier comprising amplifying means including an electron control device having control and output electrodes, first circuit means coupling the AC input signal to said electron control device, bias circuit means connecting a predetermined bias voltage to the control electrode of said electron control device for biasing the same substantially to its quiescent operating point, feedback circuit means including a diode and a capacitor connected between the output and control electrodes of said electron control device, said diode connected between the output electrode of said electron control device and said capacitor to charge said capacitor by an output signal of one polarity from said electron control device exceeding said predetermined bias voltage to raise the operating point of said electron control device from said substantially quiescent condition to permit the passing of the AC input signal of a polarity opposite said one polarity substantially free of distortion.
Claim 3
Dependent Claim
23 words
The automatic bias controlled amplifier circuit of claim 1 wherein said capacitor is connected between a reference potential and said feedback circuit means.
Claim 4
Dependent Claim
76 words
The automatic bias controlled amplifier circuit of claim 6 wherein said electron control device is a transistor and said diode acts to charge said capacitor on one of said positive and negative swings of said AC signal to raise the operating point of said transistor from said quiescent point, said capacitor acting to maintain said transistor substantially at said raised operating point during the other one of said positive and negative swings of said AC signal.
Claim 5
Dependent Claim
17 words
The automatic bias controlled amplifier circuit of claim 3 wherein said transistor is of the NPN type.
Claim 6
Dependent Claim
17 words
The automatic bias controlled amplifier circuit of claim 3 wherein said transistor is of the PNP type.
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) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |