US4752744A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Balanced transformer-less amplifier circuit
Assignee: Toshiba Corp
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Filing: 1987-06-04
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Granted: 1988-06-21
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Expires: 2007-06-04
Abstract
Abstract A balanced transformer-less amplifier having a pair of power amplifers connected in parallel for outputting amplified signals of opposite polarity, offset output detection circuit coupled to the amplifiers for detecting the difference in voltage level between the outputs of the two power amplifiers, and a preamplifier responsive to the offset output detection circuit both for operating the pair of power amplifiers on only a single power source voltage and for compensating for the difference in voltage level between the outputs of the two power amplifiers.
Inventors
- 👤 Hidehiko Aoki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:35
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/20; H03F3/21; H03F3/26; H03F1/00; H03F1/34; H03F3/68
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
85 words
A balanced transformer-less amplifier, comprising: a pair of power amplifiers connected in parallel for outputting amplified signals of opposite polarity; offset output detection means coupled to the amplifiers for detecting the difference in voltage level between the outputs of the two power amplifiers; and preamplifier means responsive to the offset output detection means both for operating the pair of power amplifiers on only a single power source voltage and for compensating for the difference in voltage level between the outputs of the two power amplifiers.
Claim 2
Dependent Claim
85 words
A balanced transformer-less amplifier, comprising: a pair of power amplifiers connected in parallel for outputting amplified signals of opposite polarity; offset output detection means coupled to the amplifiers for detecting the difference in voltage level between the outputs of the two power amplifiers; and preamplifier means responsive to the offset output detection means both for operating the pair of power amplifiers on only a single power source voltage and for compensating for the difference in voltage level between the outputs of the two power amplifiers.
Claim 3
Dependent Claim
40 words
The amplifier of claim 1 wherein the preamplifier means includes a pair of differentially connected transistors, one transistor connected to the offset output detection means having an emitter current density smaller than the emitter current density of the other transistor.
Claim 4
Dependent Claim
27 words
The balanced transformer-less amplifier of claim 2 wherein the one transistor connected to the offset output detection means has an emitter area greater than the other transistor.
Claim 5
Dependent Claim
14 words
The balanced transformer-less amplifier of claim 3 wherein each transistor is a PNP transistor.
Claim 6
Dependent Claim
22 words
The balanced transformer-less amplifier of claim 4 wherein each transistor has an emitter-collector path connected for receiving the single power source voltage.
Claim 7
Dependent Claim
24 words
The balanced transformer-less amplifier of claim 3 wherein the ratio of the larger emitter area to the smaller emitter area is at least 2:1.
Claim 8
Dependent Claim
49 words
The balanced transformer-less amplifier of claim 2 wherein the preamplifier includes a pair of current sources each corresponding to one of the transistors, the current source corresponding to the transistor connected to the offset output detection means having a current smaller than the current of the other current source.
Claim 9
Dependent Claim
55 words
The balanced transformer-less amplifier of claim 2 wherein the preamplifier includes a pair of collector load resistor means each corresponding to one of the transistors the collector load resistor means corresponding to the transistor connected to the offset output detection means having a resistance larger than the resistance of the other collector load resistor means.
Claim 10
Dependent Claim
42 words
The balanced transformer-less amplifier of claim 2 wherein the power amplifiers are non-inversed type, the input of each power amplifier is connected to a corresponding one of the transistors, and the output of each power amplifier is coupled to the opposite transistor.
Claim 11
Dependent Claim
43 words
The balanced transformer-less amplifier of claim 2 wherein the power amplifiers are inversed type, the input of each power amplifier is connected to a corresponding one of the transistors, and the output of each power amplifier is coupled to the same corresponding transistor.
References Cited (Backward Citations)
US4698599A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-06-21 | 1991-12-21 | 1992-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-21 | 1995-12-21 | 1996-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-21 | 1999-12-21 | 2000-06-21 | $7700.00 | Window Closed / Lapsed |