US3660686A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ramp generator and variable duty-cycle switching circuit
Assignee: Westinghouse Electric Corp
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Filing: 1970-04-29
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Granted: 1972-05-02
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Expires: 1990-04-29
Abstract
Abstract A low noise level adjustable solid state circuit for controlling the power reaching a load. A sawtooth ramp generator is powered by a DC analog control voltage and delivers a signal to the primary control winding of a square loop core transformer, the secondary winding of which controls the operation of a pair of solid state thyristor switches. The ramp generator, in one embodiment produces a sawtooth signal which is variable in amplitude and which rides on top of a variable DC voltage level and, in another embodiment, produces a sawtooth signal of constant amplitude and which rides on top of a variable DC voltage level. The secondary winding of the transformer provides gating signals to the thyristor switches only when the trailing edges of the gate pulses occur within the half-cycle of positive anode bias.
Inventors
- 👤 Nicholas G Muskovac
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:23
CPC Classifications
G; G05; G05F; G05F1/00; G05F1/10; G05F1/12; G05F1/40; G05F1/44; G05F1/45; G05F1/452
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
225 words
A solid state ramp generator operating in response to a low level DC input, the generator comprising: a pair of input terminals and a pair of output terminals; means for delivering DC power to said input terminals; a solid state switching element having an anode, a cathode, and an anode-gate, said switching element having a conducting mode and a non-conducting mode; means for instantaneously applying a portion of said DC power, in the form of a voltage, to the anode-gate of said switching element; energy storage means associated with the output terminals and the anode of said switching element, said storage means adapted to store energy received from said power delivering means; perioddetermining means associated with said energy storage means for defining, with said storage means, the period of said generator; means for transmitting information, proportional to the energy stored by said energy storage means, to said output terminals; and base voltage means for maintaining a DC voltage across said output terminals at all times during the operation of the generator; the anode and the anode-gate of said switching element being associated in such a manner that said switching element switches to its conductive mode in response to the energy stored by said storage means, said switching element causing the discharge of said energy storage means when said switching element is in its conductive mode.
Claim 2
Dependent Claim
225 words
A solid state ramp generator operating in response to a low level DC input, the generator comprising: a pair of input terminals and a pair of output terminals; means for delivering DC power to said input terminals; a solid state switching element having an anode, a cathode, and an anode-gate, said switching element having a conducting mode and a non-conducting mode; means for instantaneously applying a portion of said DC power, in the form of a voltage, to the anode-gate of said switching element; energy storage means associated with the output terminals and the anode of said switching element, said storage means adapted to store energy received from said power delivering means; perioddetermining means associated with said energy storage means for defining, with said storage means, the period of said generator; means for transmitting information, proportional to the energy stored by said energy storage means, to said output terminals; and base voltage means for maintaining a DC voltage across said output terminals at all times during the operation of the generator; the anode and the anode-gate of said switching element being associated in such a manner that said switching element switches to its conductive mode in response to the energy stored by said storage means, said switching element causing the discharge of said energy storage means when said switching element is in its conductive mode.
Claim 3
Dependent Claim
48 words
The ramp generator defined in claim 1, and further comprising: resistor means connected in series with said energy storage element for developing a voltage directly proportional to the input from said power delivering means, said energy storage element and said resistor being connected directly across said output terminals.
Claim 4
Dependent Claim
49 words
The ramp generator recited in claim 2, and further comprising: a voltage divider associated with said power delivering means and with the anode-gate of said switching element, said voltage divider defining the instantaneous voltage impressed upon the anode-gate of said switching element when said power delivering means is operative.
Claim 5
Dependent Claim
58 words
The ramp generator defined in claim 3, wherein said switching element switches to its conductive mode when the voltage impressed upon its anode reaches a voltage positive, by a predetermined amount, with respect to its anode-gate, said voltage divider defining the voltage impressed upon said anode-gate, and said energy storage element defining the voltage impressed upon said anode.
Claim 6
Dependent Claim
29 words
The ramp generator recited in claim 4, wherein said switching element switches to its conductive mode when its anode is approximately 0.7 volts positive with respect to its anode-gate.
Claim 7
Dependent Claim
20 words
The ramp generator defined in claim 3, and further comprising: means for developing a constant voltage across said voltage divider.
Claim 8
Dependent Claim
23 words
The ramp generator recited in claim 6, wherein said means for developing a constant voltage is in the form of a diode chain.
Claim 9
Dependent Claim
23 words
The generator defined in claim 1, and further comprising: means for filtering noise out of the power delivered by said power delivering means.
Claim 10
Dependent Claim
20 words
The ramp generator recited in claim 1, and further comprising means for limiting the current flow through said switching element.
Claim 11
Dependent Claim
191 words
A variable duty-cycle switching circuit for proportionally controlling the power reaching a load in respoNse to a low level DC input signal, the circuit comprising: a variable source of DC power; ramp generator means for receiving said DC power and for issuing a signal, the amplitude of which is proportional to the amplitude of the output of said DC power source; base voltage means in said ramp generator means for maintaining a DC voltage across the output of said generator at all times during its operation; threshold level detection means associated with the output of said ramp generator and adapted to become conductive when the amplitude of the output signal from said ramp generator is above a predetermined threshold level; a load; and AC power source associated with said load; switching means for interrupting the path between said AC power source and said load, power reaching the load only when said switching means are conductive; and means intermediate said switching means and said threshold level detector for activating said switching means when said threshold level detector indicates that the signal output of said ramp generator is above said predetermined voltage level.
Claim 12
Dependent Claim
191 words
A variable duty-cycle switching circuit for proportionally controlling the power reaching a load in respoNse to a low level DC input signal, the circuit comprising: a variable source of DC power; ramp generator means for receiving said DC power and for issuing a signal, the amplitude of which is proportional to the amplitude of the output of said DC power source; base voltage means in said ramp generator means for maintaining a DC voltage across the output of said generator at all times during its operation; threshold level detection means associated with the output of said ramp generator and adapted to become conductive when the amplitude of the output signal from said ramp generator is above a predetermined threshold level; a load; and AC power source associated with said load; switching means for interrupting the path between said AC power source and said load, power reaching the load only when said switching means are conductive; and means intermediate said switching means and said threshold level detector for activating said switching means when said threshold level detector indicates that the signal output of said ramp generator is above said predetermined voltage level.
Claim 13
Dependent Claim
38 words
The circuit defined in claim 10, and further comprising: means intermediate said ramp generator and said threshold level detector for amplifying the signals from said ramp generator and for transmitting said amplified signals to said threshold level detector.
Claim 14
Dependent Claim
81 words
The circuit recited in claim 11, wherein said ramp generator comprises a solid state switching element having an anode, a cathode and an anode-gate; voltage delivery means for impressing a portion of the signal from said DC voltage source on the anode-gate of said switching element; and energy storage means associated with the anode of said switching element and with said DC voltage source; said switching element becoming conductive when the voltage across said energy storage means reaches a predetermined level.
Claim 15
Dependent Claim
24 words
The circuit defined in claim 12, wherein said voltage delivery means comprises a voltage divider network associated with the anode-gate of said switching element.
Claim 16
Dependent Claim
28 words
The circuit defined in claim 13, and further comprising: a diode chain connected in parallel with and adapted to provide a relatively constant voltage to said voltage divider.
Claim 17
Dependent Claim
52 words
The circuit defined in claim 14, and further comprising: a resistor associated with said DC voltage source and connected across the output terminals of said ramp generator; said resistor experiencing a voltage drop, the amplitude of which is directly proportional to the amplitude of the signal developed by said DC voltage source.
Claim 18
Dependent Claim
27 words
The circuit defined in claim 10, and further comprising a transformer for isolating said variable source of DC power from said switching means and AC power source.
Claim 19
Dependent Claim
64 words
The circuit defined in claim 16, wherein said transformer has first and secondary primary windings and first and second secondary windings, said first primary winding being in the circuit of said threshold level detection means, said second primary winding being in the circuit of said AC power source, and said first and second secondary windings being in the respective circuits of said switching means.
Claim 20
Dependent Claim
18 words
The circuit recited in claim 10, and further comprising means for slaving said switching means to one another.
Claim 21
Dependent Claim
20 words
The circuit recited in claim 10, and further comprising means for adjusting the gain of said variable duty-cycle switching circuit.
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) | 1975-05-02 | 1975-11-01 | 1976-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-02 | 1979-11-01 | 1980-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-02 | 1983-11-01 | 1984-05-02 | $7700.00 | Window Closed / Lapsed |