US5118962A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power supply backup circuit
Assignee: Toshiba Corp
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Filing: 1990-03-15
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Granted: 1992-06-02
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Expires: 2010-03-15
Abstract
Abstract Improvements to a power supply backup circuit used to backup the operation of a radio device or the like when a power supply therefor is interrupted. A reverse current preventing diode is connected such that its anode is connected to the junction point of a DC power source and a voltage stabilizing circuit and such that its cathode is connected to the stabilizing circuit. A transistor is provided which has a collector connected to the cathode of the diode, an emitter connected to one end of a capacitor, the other end of which is grounded, and a base connected to a DC power source via a first resistor, and which has a second resistor connected across the base and emitter thereof. A third resistor is further connected across the collector and emitter of the transistor.
Inventors
- 👤 Takaaki Ishii
- 👤 Masayuki Sakanishi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:16
CPC Classifications
H; H02; H02J; H02J9/00; H02J9/04; H02J9/06; H02J9/061
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
196 words
A power supply backup circuit comprising; a capacitor having a capacity large enough to backup a load; a charging circuit for charging the capacitor via current limiting circuitry; a discharging circuit for supplying the stored charge in the capacitor via a switch to a junction point of reverse current preventing circuitry and a voltage stabilizing circuit; means for detecting interruption of a current from a DC power source; control means for turning on the switch in response to a detection output from the detecting means indicative of the detection of interruption of the current from the DC power source; wherein the switch includes a transistor having a base, a collector connected to the junction point of the reverse current preventing circuitry and the voltage stabilizing circuit, and an emitter connected to the capacitor; wherein the control means includes a circuit in which the DC power source is connected to the base of the transistor via a first resistor and in which a junction point of the emitter and the base of the transistor connected via a second resistor; and wherein the charging circuit includes a circuit for charging the capacitor via the first and second resistors.
Claim 2
Dependent Claim
196 words
A power supply backup circuit comprising; a capacitor having a capacity large enough to backup a load; a charging circuit for charging the capacitor via current limiting circuitry; a discharging circuit for supplying the stored charge in the capacitor via a switch to a junction point of reverse current preventing circuitry and a voltage stabilizing circuit; means for detecting interruption of a current from a DC power source; control means for turning on the switch in response to a detection output from the detecting means indicative of the detection of interruption of the current from the DC power source; wherein the switch includes a transistor having a base, a collector connected to the junction point of the reverse current preventing circuitry and the voltage stabilizing circuit, and an emitter connected to the capacitor; wherein the control means includes a circuit in which the DC power source is connected to the base of the transistor via a first resistor and in which a junction point of the emitter and the base of the transistor connected via a second resistor; and wherein the charging circuit includes a circuit for charging the capacitor via the first and second resistors.
Claim 3
Dependent Claim
104 words
A power supply backup circuit comprising: a first load connected directly to a DC power source and requiring no backup; a second load requiring a backup connected via reverse current preventing circuitry and voltage stabilizing circuitry to the DC power source; a capacitor having a capacity large enough to backup the second load; a switch connected between the capacitor and a junction point between the reverse current preventing circuitry and the voltage stabilizing circuitry; a charging circuit for charging the capacitor via current limiting circuitry; and control means for turning on the switch when an electric current from the DC power source is interrupted.
Claim 4
Dependent Claim
104 words
A power supply backup circuit comprising: a first load connected directly to a DC power source and requiring no backup; a second load requiring a backup connected via reverse current preventing circuitry and voltage stabilizing circuitry to the DC power source; a capacitor having a capacity large enough to backup the second load; a switch connected between the capacitor and a junction point between the reverse current preventing circuitry and the voltage stabilizing circuitry; a charging circuit for charging the capacitor via current limiting circuitry; and control means for turning on the switch when an electric current from the DC power source is interrupted.
Claim 5
Dependent Claim
54 words
A power supply backup circuit according to claim 2 wherein the charging circuit includes: a first charging circuit for directly charging the capacitor with an output of the DC power source; and a second charging circuit for charging the capacitor with the output of the DC power source via the reverse current preventing circuitry.
Claim 6
Dependent Claim
36 words
A power supply backup circuit according to claim 2 wherein the reverse current preventing circuitry includes a diode having an anode connected to the DC power source and a cathode connected to the voltage stabilizing circuitry.
Claim 7
Dependent Claim
104 words
A power supply backup circuit according to claim 2, wherein the switch includes a transistor having a base, a collector connected to a junction point of the reverse current preventing circuitry and the voltage stabilizing circuitry, and an emitter connected to the capacitor; the control means includes a circuit in which the DC power source is connected to the base of the transistor via a first resistor and in which a junction point of the emitter and the base of the transistor connected via a second resistor; and the charging circuit includes a circuit for charging the capacitor via the first and second resistors.
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) | 1995-06-02 | 1995-12-02 | 1996-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-02 | 1999-12-02 | 2000-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-02 | 2003-12-02 | 2004-06-02 | $7700.00 | Window Closed / Lapsed |