US3904931A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overvoltage protection circuit
Assignee: RCA Corp
•
Filing: 1973-08-03
•
Granted: 1975-09-09
•
Expires: 1993-08-03
Abstract
Abstract A silicon controlled rectifier (SCR) is connected at its cathode to one terminal of the device to be protected and at its anode to the other terminal of the device. When an overvoltage occurs, a zener diode connected between the trigger gate and anode of the SCR is driven into conduction in the zener mode and this causes anode-to-cathode conduction through the SCR, placing a low impedance path across the device to be protected. When the overvoltage is removed, the space-charge at the trigger electrode-bias electrode junction of the SCR is quickly dissipated, thereby opening the low impedance path.
Inventors
- 👤 Arthur John Leidich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:58
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/04; H02H9/041
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
200 words
An alternating current overvoltage protection circuit, for protecting a load having two signal input terminals from a transient overvoltage component of a given polarity in excess of the normal peak amplitude of an alternating current signal supplied to said signal input terminals, comprising: a reverse blocking tetrode thyristor having an anode terminal for connection to one of said load terminals and a cathode terminal for connection to the other of said load terminals, said thyristor also having a cathode gate terminal and an anode gate terminal; a Zener diode connected at the anode and cathode terminals thereof, respectively, to the cathode gate terminal and the anode terminal of said thyristor; and means for continuously applying a direct current reverse bias signal of said given polarity to said anode gate terminal, whereby said thyristor is normally non-conductive for either polarity of said alternating current signal, is triggered into a conductive state by current supplied through said Zener diode to said cathode gate terminal in response to said transient overvoltage component of said given polarity and is rapidly returned to a non-conductive state in response to said reverse bias signal upon termination of said transient and reversal of said alternating current signal.
Claim 2
Dependent Claim
200 words
An alternating current overvoltage protection circuit, for protecting a load having two signal input terminals from a transient overvoltage component of a given polarity in excess of the normal peak amplitude of an alternating current signal supplied to said signal input terminals, comprising: a reverse blocking tetrode thyristor having an anode terminal for connection to one of said load terminals and a cathode terminal for connection to the other of said load terminals, said thyristor also having a cathode gate terminal and an anode gate terminal; a Zener diode connected at the anode and cathode terminals thereof, respectively, to the cathode gate terminal and the anode terminal of said thyristor; and means for continuously applying a direct current reverse bias signal of said given polarity to said anode gate terminal, whereby said thyristor is normally non-conductive for either polarity of said alternating current signal, is triggered into a conductive state by current supplied through said Zener diode to said cathode gate terminal in response to said transient overvoltage component of said given polarity and is rapidly returned to a non-conductive state in response to said reverse bias signal upon termination of said transient and reversal of said alternating current signal.
Claim 3
Dependent Claim
23 words
The overvoltage protection circuit set forth in claim 1 wherein said thyristor and said Zener diode are integrated upon a common semiconductor substrate.
References Cited (Backward Citations)
US3271587A
Cited
US3303360A
Cited
US3699406A
Cited
US3475653A
Cited
US3407335A
Cited
US3573550A
Cited
US3638042A
Cited
US3626249A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |