Patent US3579132A successfully refreshed from Google Patents.
US3579132A
Expired / Lapsed
US
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Class {37 d{38 {0 linear audio amplifier
Assignee: LTV LING ALTEC Inc
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Filing: 1969-11-14
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Granted: 1971-05-18
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Expires: 1989-11-14
Abstract
Abstract An audio frequency amplifier, useful to DC in which a pulsewidth modulated signal is formed from the audio frequency signal. Each excursion of the pulse-width signal is cut in half with respect to time by an appropriately timed square-wave and plural logic gates. The resulting waveforms are passed without distortion by pulse transformers. Plural rectifiers and low-pass filters re-form the pulse-width modulated signal. This signal is impressed upon switching power transistors. These give a greatly amplified power output, which is the same type of amplitudevarying waveform as the input audio signal, upon the current flowing through a small choke to the load. The load may have any phase angle without incurring distortion of the output waveform. Half-bridge, quarter-bridge, full-bridge, and plural phase embodiments are described.
Inventors
- 👤 James A Ross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:36
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/20; H03F3/21; H03F3/217; H03F3/2178
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
277 words
An electrical amplifier comprising; a. comparator apparatus (1 to 24) having feedback to form a pulse-width modulated signal (19'') from an amplitude-varying input signal (1'') and a triangular wave amplitude-varying signal (8''), b. first and second series of gating means (39a & c; 39b & d connected to said comparator means, each said series supplied with a square wave signal (23'' or 20'') time related to said triangular wave signal to alternately pass said pulse-width modulated signal in successive halves of the duration of each pulse width, c. a first type transformer (42, 56) having a primary and plural secondaries (43 & 48), said primary connected to one of said first series of said gating means (39a), d. a second type transformer (53, 57) having a primary and one secondary (as 54), the primary of said second type transformer connected to one of said second series of said gating means (39b), e. a plurality of low-pass filters (45, 46, 47; 60, 61, 62) equal in number to the number of said gating means in said first series, each said filter connected to secondaries of both a first and a second type transformer, f. a power amplifier having at least two active elements (67 & 68) in opposed groups, and an output, g. a connection (64) from one of said plurality of low-pass filters to one (67) of said active elements, h. a connection (66) from another of said plurality of low-pass filters to a said active element (68) that is in the group opposed to said one active element, i. a load (72), and j. a connection from the output of said power amplifier to said load.
Claim 2
Dependent Claim
277 words
An electrical amplifier comprising; a. comparator apparatus (1 to 24) having feedback to form a pulse-width modulated signal (19'') from an amplitude-varying input signal (1'') and a triangular wave amplitude-varying signal (8''), b. first and second series of gating means (39a & c; 39b & d connected to said comparator means, each said series supplied with a square wave signal (23'' or 20'') time related to said triangular wave signal to alternately pass said pulse-width modulated signal in successive halves of the duration of each pulse width, c. a first type transformer (42, 56) having a primary and plural secondaries (43 & 48), said primary connected to one of said first series of said gating means (39a), d. a second type transformer (53, 57) having a primary and one secondary (as 54), the primary of said second type transformer connected to one of said second series of said gating means (39b), e. a plurality of low-pass filters (45, 46, 47; 60, 61, 62) equal in number to the number of said gating means in said first series, each said filter connected to secondaries of both a first and a second type transformer, f. a power amplifier having at least two active elements (67 & 68) in opposed groups, and an output, g. a connection (64) from one of said plurality of low-pass filters to one (67) of said active elements, h. a connection (66) from another of said plurality of low-pass filters to a said active element (68) that is in the group opposed to said one active element, i. a load (72), and j. a connection from the output of said power amplifier to said load.
Claim 3
Dependent Claim
112 words
An amplifier according to claim 1, in which said comparator apparatus is comprised of; a. a source of triangular waveform (5, 8), b. a comparator (3) connected to said source of triangular waveform and receiving said amplitude-varying input signal (1'') to give an amplitude transition each time said triangular waveform becomes greater or less in amplitude than the amplitude of said input signal, c. plural inverters (42a, b, c, d, e) connected to said comparator to form comparator-related outputs (23'') d. a flip-flop (7), and e. connections (19, 20, 23, 24) from said comparator, said inverTers, and said flip-flop, to said first and second series of gating means (39a, b, c, d).
Claim 4
Dependent Claim
63 words
An amplifier according to claim 2, in which said source of triangular waveform is composed of; a. a square wave generator (5, 7), and b. an integrator (8) connected to said square wave generator; and which additionally includes; c. a connection from said square wave generator to said first (39a, c) and second (39b, d) series of gating means through plural said inverters.
Claim 5
Dependent Claim
30 words
An amplifier according to claim 3, in which; a. each of said gating means (39a, b, c, d) is a NAND gate, having an input from plural said comparator-related outputs.
Claim 6
Dependent Claim
30 words
An amplifier according to claim 1, in which said transformers are; a. stepdown in ratio from primary to secondary, and b. have nonconductive isolation between each primary and each secondary.
Claim 7
Dependent Claim
41 words
An amplifier according to claim 1, in which each of said low-pass filters includes; a. a diode (44), and b. inductive (45, 46) and capacitive (47) filter elements, having a cutoff frequency above the frequency of said pulse-width modulated signal (19'').
Claim 8
Dependent Claim
21 words
An amplifier according to claim 1, in which; a. each of said opposed active elements (67, 68) is a switching-type transistor.
Claim 9
Dependent Claim
42 words
An amplifier according to claim 1, in which said connection (par. j) from the output of said power amplifier to said load (72) includes; a. a reactor (71) having negligible inductive reactance at the highest frequency of said amplitude-varying input signal (1'').
Claim 10
Dependent Claim
38 words
An amplifier according to claim 1, in which; a. said first and said second series of gating means each have two gating means, b. there are two said first-type transformers, and c. there are two said second-type transformers.
Claim 11
Dependent Claim
41 words
An amplifier according to claim 1, in which there are; a. four said first-type transformers, b. four said second-type transformers; and in addition, c. connections to parallel two of each said type transformers with two other of the corresponding said type.
Claim 12
Dependent Claim
90 words
An amplifier according to claim 1, which additionally includes; a. a second set (Ia) of said first and second series of said gating means, b. an inverter (930 connected from the source of said input signal (1) to said second set of gating means, c. connections (19, 20, 23 24) from the first set of said gating means to four of said first- and second-type transformers, and d. connections (19a, 20a, 23a, 24a) from said second set of said gating means to four more of said first- and second-type transformers.
Claim 13
Dependent Claim
51 words
An amplifier according to claim 1, in which there are; a. only said first series of said gating means, having two gating means, b. only one said first-type transformer (42), c. only one said second-type transformer (53), d. only one said low-pass filter, and e. only one said active element (67).
Claim 14
Dependent Claim
62 words
An amplifier according to claim 1, which additionally includes; a. a second comparator apparatus (Ia) to form a pulse-width modulated signal from a second amplitude-varying input signal, b. connections from said second comparator apparatus to at least two additional opposed active elements (67a, 68a), c. an additional load (72a), and d. connections from said additional opposed active elements to said additional load.
Claim 15
Dependent Claim
86 words
An amplifier according to claim 1, which additionally includes; a. second and third comparator apparatus (Ia, Ib) to form a pulse-width modulated signal from a second and a third amplitude-varying input signal, respectively, b. connections from said second and third comparator apparatus to at least two additional second (67a, 68a) and also third (67b, 68b) opposed active elements, respectively, c. additional second and third loadS (99a, 99b), and d. connections from additional said second and third opposed active elements to said second and third loads, respectively.
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) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |