US5130883A
Expired / Lapsed
US
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Circuit for overvoltage protection
Assignee: Aumovio Systems Inc
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Filing: 1990-02-26
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Granted: 1992-07-14
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Expires: 2010-02-26
Abstract
Abstract In a circuit for overvoltage protection of a low voltage device (11) arranged to control a load (12) an energy storage capacitor (17) is connected to charge from supply (+V) while the device is controlled from a control circuit (100). During overvoltage, the controller is disconnected by switch means (15) and capacitor connected by switch means (16, 18) across the device to maintain it in an on state so that overvoltage device damage is prevented. The circuit is suited to transitory overvoltage conditions such as automotive load dump and to integration with the controlled device.
Inventors
- 👤 Arthur J. Edwards
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:15
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/06; H03K17/063; H03K17/08; H03K17/082; H03K17/0822; H02; H02H; H02H9/00; H02H9/04
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
142 words
A circuit arrangement for protecting a low voltage device, arranged in use to control a load, from an overvoltage condition, including an input for receiving a load control signal, a low voltage device having a control electrode and coupled across a supply voltage, said low voltage device arranged in use to control a load; and switch means for connecting said load control signal to said control electrode of said low voltage device to control said load; said switch means being responsive to an overvoltage condition in said supply voltage to disconnect said load control signal from said control electrode and connect said control electrode of said low voltage device to a source of low voltage device on signal to hold said low voltage device fully on and provide a low voltage thereacross to protect said low voltage device and provide overvoltage protection.
Claim 2
Dependent Claim
142 words
A circuit arrangement for protecting a low voltage device, arranged in use to control a load, from an overvoltage condition, including an input for receiving a load control signal, a low voltage device having a control electrode and coupled across a supply voltage, said low voltage device arranged in use to control a load; and switch means for connecting said load control signal to said control electrode of said low voltage device to control said load; said switch means being responsive to an overvoltage condition in said supply voltage to disconnect said load control signal from said control electrode and connect said control electrode of said low voltage device to a source of low voltage device on signal to hold said low voltage device fully on and provide a low voltage thereacross to protect said low voltage device and provide overvoltage protection.
Claim 3
Dependent Claim
70 words
A circuit as claimed in claim 1 and wherein said switch means comprises two complementary switches arranged such that said load control signal is connected to said low voltage device control electrode during normal operation and disconnected therefrom during said overvoltage protection and said source of low voltage device on signal is disconnected from said low voltage device control electrode during normal operation and connected thereto during said overvoltage protection.
Claim 4
Dependent Claim
21 words
A circuit as claimed in claim 1 and wherein said source of device low voltage on signal comprises energy storage means.
Claim 5
Dependent Claim
24 words
A circuit as claimed in claim 3 and including further switch means to connect said energy storage means to a supply during normal operation.
Claim 6
Dependent Claim
59 words
A circuit as claimed in claim 3 wherein said low voltage device is a three terminal device and including an additional switch to connect said energy storage means across two terminals of said low voltage device, one of said terminals corresponding to said control electrode, during said overvoltage protection to hold said low voltage device in a preferred condition.
Claim 7
Dependent Claim
20 words
A circuit as claimed in claim 3 and including means to discharge said energy storage means during said overvoltage protection.
Claim 8
Dependent Claim
29 words
A circuit as claimed in claim 6 and wherein said overvoltage protection exists for a duration and wherein discharging of said energy storage means determines said overvoltage protection duration.
Claim 9
Dependent Claim
18 words
A circuit as claimed in claim 7 and wherein said duration overvoltage protection exceeds automotive load dump duration.
Claim 10
Dependent Claim
19 words
A circuit as claimed in claim 1 and wherein said device low voltage is a field effect transistor switch.
Claim 11
Dependent Claim
18 words
A circuit as claimed in claim 1 in which said switch means is substantially in integrated circuit form.
Claim 12
Dependent Claim
155 words
A circuit arrangement for protecting a low voltage device, arranged in use to control a load, from an overvoltage condition, including an input for receiving a load control signal derived from a first power source signal, a low voltage device having a control electrode and coupled across said first power source signal, said low voltage device arranged in use to control a load; means for connecting said load control signal to said control electrode of said low voltage device to control said load; and switch means being responsive to an overvoltage condition in said fist power source signal to connect said control electrode of said low voltage device to a source of low voltage device on signal derived from a second power source signal different from said first power source signal to hold said low voltage device fully on and provide a low voltage thereacross to protect said low voltage device and provide overvoltage protection.
Claim 13
Dependent Claim
155 words
A circuit arrangement for protecting a low voltage device, arranged in use to control a load, from an overvoltage condition, including an input for receiving a load control signal derived from a first power source signal, a low voltage device having a control electrode and coupled across said first power source signal, said low voltage device arranged in use to control a load; means for connecting said load control signal to said control electrode of said low voltage device to control said load; and switch means being responsive to an overvoltage condition in said fist power source signal to connect said control electrode of said low voltage device to a source of low voltage device on signal derived from a second power source signal different from said first power source signal to hold said low voltage device fully on and provide a low voltage thereacross to protect said low voltage device and provide overvoltage protection.
Claim 14
Dependent Claim
74 words
A circuit as claimed in claim 11 and wherein said switch means comprises two complementary switches arranged such that said load control signal is connected to said control electrode of said low voltage device during normal operation and disconnected therefrom during said overvoltage protection and said source of low voltage device on signal is disconnected from said control electrode of said low voltage device during normal operation and connected thereto during said overvoltage protection.
Claim 15
Dependent Claim
28 words
A circuit as claimed in claim 11 and wherein said source of device low voltage on signal comprises energy storage means for developing said second power source signal.
Claim 16
Dependent Claim
30 words
A circuit as claimed in claim 13 and including further switch means to connect said energy storage means to a supply providing said first power source signal during normal operation.
Claim 17
Dependent Claim
57 words
A circuit as claimed in claim 13 wherein said low voltage device is a three terminal device and including an additional switch to connect said energy storage means across two terminals of said device, one of said terminals corresponding to said control electrode, during said overvoltage protection to hold said low voltage device in a preferred condition.
Claim 18
Dependent Claim
20 words
A circuit as claimed in claim 13 and including means to discharge said energy storage means during said overvoltage protection.
Claim 19
Dependent Claim
29 words
A circuit as claimed in claim 16 and wherein said overvoltage protection exists for a duration and wherein discharging of said energy storage means determines said overvoltage protection duration.
Claim 20
Dependent Claim
18 words
A circuit as claimed in claim 17 and wherein said duration overvoltage protection exceeds automotive load dump duration.
Claim 21
Dependent Claim
19 words
A circuit as claimed in claim 11 and wherein said device low voltage is a field effect transistor switch.
Claim 22
Dependent Claim
38 words
A circuit as claimed in claim 11 wherein said second power source signal is independent of said first power source signal during load dump at least when said second power source signal exceeds said first power source signal.
Claim 23
Dependent Claim
16 words
A circuit as claimed in claim 3 wherein said energy storage device comprises a chargeable capacitor.
Claim 24
Dependent Claim
16 words
A circuit as claimed in claim 5 wherein said energy storage device comprises a chargeable capacitor.
Claim 25
Dependent Claim
16 words
A circuit as claimed in claim 6 wherein said energy storage device comprises a chargeable capacitor.
Claim 26
Dependent Claim
16 words
A circuit as claimed in claim 13 wherein said energy storage device comprises a chargeable capacitor.
Claim 27
Dependent Claim
16 words
A circuit as claimed in claim 15 wherein said energy storage device comprises a chargeable capacitor.
Claim 28
Dependent Claim
16 words
A circuit as claimed in claim 16 wherein said energy storage device comprises a chargeable capacitor.
Claim 29
Dependent Claim
49 words
A circuit as claimed in claim 7 which includes means, in response to said discharging of said energy storage device, for causing said switch means to reconnect said load control signal to said control electrode and disconnect said source of low voltage device on signal from said control electrode.
Claim 30
Dependent Claim
41 words
A circuit according to claim 27 wherein said reconnection means comprising voltage sense means which senses voltage applied across said low voltage device and implements said reconnection in response to said sensed voltage across said low voltage device exceeding a limit.
Claim 31
Dependent Claim
49 words
A circuit as claimed in claim 17 which includes means, in response to said discharging of said energy storage device, for causing said switch means to reconnect said load control signal to said control electrode and disconnect said source of low voltage device on signal from said control electrode.
Claim 32
Dependent Claim
41 words
A circuit according to claim 29 wherein said reconnection means comprises voltage sense means which senses voltage applied across said low voltage device and implements said reconnection in response to said sensed voltage across said low voltage device exceeding a limit.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-07-14 | 1996-01-13 | 1996-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-14 | 2000-01-13 | 2000-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-14 | 2004-01-13 | 2004-07-14 | $7700.00 | Window Closed / Lapsed |