US3577010A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zero point switching circuit for turn-on of gate-controlled conducting devices
Assignee: Motorola Solutions Inc
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Filing: 1969-01-31
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Granted: 1971-05-04
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Expires: 1989-01-31
Abstract
Abstract A zero point switching circuit for an SCR coupled in series with an AC source and a load is described. The combination of a switch, a first diode and a voltage divider is coupled across the source. The variable tap of the divider is coupled via a second diode and a first capacitor to the first diode. A second capacitor is coupled across the voltage divider. When the switch is closed, the first capacitor charges during one-half cycle toward a voltage level determined by the divider. The discharge path for the first capacitor is provided by a three-layer diode coupled between the control electrode of the SCR and the first capacitor. When the line voltage decreases prior to the next half cycle, the first capacitor voltage exceeds the threshold voltage of the three-layer diode whereby this capacitor discharges through the SCR into the second capacitor. The second capacitor charges to a voltage sufficient to render the three-layer diode nonconductive and then discharges through the voltage divider to permit the first capacitor to again discharge into the gate of the SCR. As a result, the first capacitor repetitively discharges into the gate of the SCR with large current spikes at or just prior to the zero point of the line voltage.
Inventors
- 👤 Edward N Freyling Jr
- 👤 Robert E Gregson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:39
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/08; H02M1/083; H03; H03K; H03K17/00; H03K17/13; H03K17/136
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
288 words
A control circuit for regulating turn-on of a gate-controlled semiconductor device connected in circuit relation with an alternating source in the load, said circuit comprising: a. first unidirectional current means having first and second electrodes and poled to pass current flowing from said first to second electrodes; b. a voltage divider having first, second and third terminals, the first terminal of said divider being coupled to the first electrode of said current means; the second electrode of said first current means and the second terminal of said voltage divider being coupled across the alternating source, the voltage appearing at the third terminal of said divider being less than the voltage between the first and second terminals thereof; c. a first capacitor coupled between the first and second terminals of said voltage divider; d. second unidirectional current means having first and second electrodes and poled to pass current flowing from said first and second electrodes, the first electrode of said second current means being coupled to the third terminal of said voltage divider; e. a second capacitor coupled between the first electrode of said first current means and the second electrode of said second current means; and f. a voltage-controlled semiconductor device coupled between the second electrode of said second current means and the gate electrode of said gate-controlled device, said voltagecontrolled device becoming conductive when the voltage thereacross reaches a predetermined threshold, said second capacitor being charged to a voltage exceeding the threshold of said voltage-controlled device by the alternating source whereby said second capacitor discharges through the gate electrode of the gate control device and charges said first capacitor, said first capacitor discharging through said voltage divider whereupon said second capacitor repetitively discharges through said gate-controlled device.
Claim 2
Dependent Claim
288 words
A control circuit for regulating turn-on of a gate-controlled semiconductor device connected in circuit relation with an alternating source in the load, said circuit comprising: a. first unidirectional current means having first and second electrodes and poled to pass current flowing from said first to second electrodes; b. a voltage divider having first, second and third terminals, the first terminal of said divider being coupled to the first electrode of said current means; the second electrode of said first current means and the second terminal of said voltage divider being coupled across the alternating source, the voltage appearing at the third terminal of said divider being less than the voltage between the first and second terminals thereof; c. a first capacitor coupled between the first and second terminals of said voltage divider; d. second unidirectional current means having first and second electrodes and poled to pass current flowing from said first and second electrodes, the first electrode of said second current means being coupled to the third terminal of said voltage divider; e. a second capacitor coupled between the first electrode of said first current means and the second electrode of said second current means; and f. a voltage-controlled semiconductor device coupled between the second electrode of said second current means and the gate electrode of said gate-controlled device, said voltagecontrolled device becoming conductive when the voltage thereacross reaches a predetermined threshold, said second capacitor being charged to a voltage exceeding the threshold of said voltage-controlled device by the alternating source whereby said second capacitor discharges through the gate electrode of the gate control device and charges said first capacitor, said first capacitor discharging through said voltage divider whereupon said second capacitor repetitively discharges through said gate-controlled device.
Claim 3
Dependent Claim
54 words
The circuit in accordance with claim 1 further comprising a third unidirectional current means having first and second electrodes and poled to pass current flowing from said first to second electrodes, said first electrode being coupled to the voltage-controlled device, said second electrode being coupled to the gate electrode of said gate control device.
Claim 4
Dependent Claim
24 words
The circuit in accordance with claim 2 further comprising switching means connected in circuit relation with said first current means and said voltage divider.
Claim 5
Dependent Claim
15 words
The circuit in accordance with claim 3 wherein said voltage-controlled device is a three-layer diode.
Claim 6
Dependent Claim
15 words
The circuit in accordance with claim 4 wherein said gate-controlled device is a silicon-controlled rectifier.
Claim 7
Dependent Claim
20 words
The circuit in accordance with claim 5 wherein said second capacitor is relatively large with respect to said first capacitor.
Claim 8
Dependent Claim
396 words
A control circuit for regulating turn-on of gate-controlled semiconductor device connected in circuit relation with an alternating source and a load, said circuit comprising: a. switching means having first and second terminals, the first terminal of said switching means being connected in circuit relation with the alternating source; b. first unidirectional current means having first and second electrodes and poled to pass current flowing from said first to second electrode, said second electrode being coupled to the second terminal of said switching means; c. a voltage divider having first, second and third terminals, the first terminal of said divider being coupled to the first electrode of said first current means, the second terminal of said divider being coupled in circuit relation with the alternating source, the voltage at the third terminal of said divider being less than the voltage appearing between the first and second terminals thereof; d. a first capacitor coupled between the first and second terminals of said voltage divider; e. the second unidirectional current means having first and second electrodes and poled to pass current flowing from said first to second electrode, the first electrode of said second current means being coupled to the third terminal of said divider; f. a second capacitor coupled between the first terminal of said divider and the second electrode of said second current means, said second capacitor being relatively large with respect to said first capacitor; g. a voltage-controlled semiconductor device having first and second electrodes, said device becoming conductive only when the voltage thereacross reaches a predetermined threshold, the first electrode of said device being coupled to the second electrode of said second current means; and h. third unidirectional current means having first and second electrodes and poled to pass current flowing from said first to second electrodes, said first electrode being coupled to the second electrode of said control device, said second electrode being coupled to the gate electrode of said gate-controlled device, the actuation of said switching means resulting in the charging of said second capacitor to a voltage which causes said voltage control device to pass current to the gate electrode of said gate control device and thereby charge said first capacitor and render the voltage-controlled device nonconductive, the first capacitor discharging through said voltage divider to thereby cause said second capacitor tO repetitively discharge through the gate electrode of said gate-controlled device.
Claim 9
Dependent Claim
396 words
A control circuit for regulating turn-on of gate-controlled semiconductor device connected in circuit relation with an alternating source and a load, said circuit comprising: a. switching means having first and second terminals, the first terminal of said switching means being connected in circuit relation with the alternating source; b. first unidirectional current means having first and second electrodes and poled to pass current flowing from said first to second electrode, said second electrode being coupled to the second terminal of said switching means; c. a voltage divider having first, second and third terminals, the first terminal of said divider being coupled to the first electrode of said first current means, the second terminal of said divider being coupled in circuit relation with the alternating source, the voltage at the third terminal of said divider being less than the voltage appearing between the first and second terminals thereof; d. a first capacitor coupled between the first and second terminals of said voltage divider; e. the second unidirectional current means having first and second electrodes and poled to pass current flowing from said first to second electrode, the first electrode of said second current means being coupled to the third terminal of said divider; f. a second capacitor coupled between the first terminal of said divider and the second electrode of said second current means, said second capacitor being relatively large with respect to said first capacitor; g. a voltage-controlled semiconductor device having first and second electrodes, said device becoming conductive only when the voltage thereacross reaches a predetermined threshold, the first electrode of said device being coupled to the second electrode of said second current means; and h. third unidirectional current means having first and second electrodes and poled to pass current flowing from said first to second electrodes, said first electrode being coupled to the second electrode of said control device, said second electrode being coupled to the gate electrode of said gate-controlled device, the actuation of said switching means resulting in the charging of said second capacitor to a voltage which causes said voltage control device to pass current to the gate electrode of said gate control device and thereby charge said first capacitor and render the voltage-controlled device nonconductive, the first capacitor discharging through said voltage divider to thereby cause said second capacitor tO repetitively discharge through the gate electrode of said gate-controlled device.
Claim 10
Dependent Claim
15 words
The circuit in accordance with claim 7 wherein said voltage-controlled device is a three-layered diode.
Claim 11
Dependent Claim
14 words
The circuit in accordance with claim 8 wherein said gate-controlled device is an SCR.
References Cited (Backward Citations)
US3335291A
Cited
US3440445A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |