US3582684A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zero point switching circuit for initiating conduction of silicon-controlled rectifiers
Assignee: Motorola Solutions Inc
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Filing: 1969-01-21
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Granted: 1971-06-01
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Expires: 1989-01-21
Abstract
Abstract A zero point switching circuit for an SCR coupled in circuit relation 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 or terminal of the divider is coupled through a second diode and a capacitor to the first diode. When the switch is closed, the capacitor charges during one-half cycle toward a voltage level determined by the divider. The discharge path for the capacitor is provided by a three-layered diode coupled between the gate electrode of the SCR and the capacitor. When the line voltage decreases prior to the next half cycle, the capacitor voltage extends the threshold level of the three-layered diode. As a result, the diode becomes conductive thereby turning on the SCR at the zero point of the AC voltage.
Inventors
- 👤 Robert E Gregson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:40
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/13; H03K17/136
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
52 words
The circuit in accordance with claim 1 further comprising 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 the gate-controlled device.
Claim 2
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 3
Dependent Claim
15 words
The circuit in accordance with claim 3 wherein said voltage-controlled device is a three-layered diode.
Claim 4
Dependent Claim
16 words
The circuit in accordance with claim 4 wherein said gate-controlled device is a silicon control rectifier.
Claim 5
Dependent Claim
17 words
The circuit in accordance with claim 5 wherein said first, second and third current means are diodes.
Claim 6
Dependent Claim
29 words
The circuit in accordance with claim 6 further comprising a resistor coupled between the second electrode of said third current means and the second terminal of said voltage divider.
Claim 7
Dependent Claim
336 words
A control circuit for regulating the turn-on time of a gate-controlled semiconductor device which is 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. a first diode having first and second electrodes, said diode being poled to pass current flowing from said first to second electrodes, 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 diode, the second terminal of said divider being coupled in circuit relation with the alternating source; d. a second diode having first and second electrodes, said diode being poled to pass current flowing from said first and second electrodes, the first electrode of said second diode being coupled to the third terminal of said voltage divider; e. a capacitor having first and second terminals, the first terminal of said capacitor being coupled to the second electrode of said second diode, the second terminal of said capacitor being coupled to the first electrode of said first diode; f. a voltage-controlled semiconductor device having first and second electrodes, said device becoming conductive when the voltage thereacross reaches a predetermined threshold, the first electrode of said device being coupled to the first terminal of said capacitor, and g. a third diode having first and second electrodes said third diode being poled to pass current flowing from said first to second electrodes, said first electrode being coupled to the second electrode of said voltage-controlled device, the second electrode of said third diode being coupled to the gate electrode of said gate-controlled device, the actuation of said switching means charging said capacitor to a voltage exceeding the threshold of said voltage-controlled device whereby a turn-on drive current is supplied to the gate electrode of said gate-controlled device.
Claim 8
Dependent Claim
15 words
The circuit in accordance with claim 8 wherein said voltage-controlled device is a three-layered diode.
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) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |