Patent US4920307A successfully refreshed from Google Patents.
US4920307A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric power source used to charge a secondary power source
Assignee: Pentax Corp
•
Filing: 1989-07-12
•
Granted: 1990-04-24
•
Expires: 2009-07-12
Abstract
Abstract Whether electronic equipment is being used or a secondary battery is being charged is detected by measuring the electric current supplied from an electric power source to the electronic equipment. The voltage level supplied to the electronic equipment is switched corresponding to the detected result. Accordingly, the secondary battery can be charged reliably and efficiently at a higher voltage level than that used by the electronic equipment and the heat generated within the electronic equipment can be reduced. Therefore, the apparatus can be made compact and the cost thereof can be reduced. Further, the constructional parts to which the voltage from the electric power source is supplied can be operated by desirable operational characteristics.
Inventors
- 👤 Kohei Iketani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:20
CPC Classifications
H; H02; H02J; H02J7/00; H02J7/90; H02J7/94; Y; Y02; Y02B; Y02B40/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
76 words
An electric power source for supplying a direct current voltage to electronic equipment having a battery which is charged by said electric power source, said electric power source comprising: first means for detecting an electric current supplied to the electronic equipment from said electric power source; and second means for adjusting an output voltage of said electric power source to one of at least two different voltages in accordance with the amount of said detected current.
Claim 2
Dependent Claim
76 words
An electric power source for supplying a direct current voltage to electronic equipment having a battery which is charged by said electric power source, said electric power source comprising: first means for detecting an electric current supplied to the electronic equipment from said electric power source; and second means for adjusting an output voltage of said electric power source to one of at least two different voltages in accordance with the amount of said detected current.
Claim 3
Dependent Claim
28 words
An electronic power source as claimed in claim 1, wherein one of said at least two voltages is used to power an electronic device in said electronic equipment.
Claim 4
Dependent Claim
24 words
An electronic power source as claimed in claim 1, wherein a first of said at least two voltages is used to charge said battery.
Claim 5
Dependent Claim
24 words
An electronic power source as claimed in claim 3, wherein said first voltage is higher than a second of said at least two voltages.
Claim 6
Dependent Claim
24 words
An electronic power source as claimed in claim 4, wherein said second voltage is used to power an electronic device in said electronic equipment.
Claim 7
Dependent Claim
16 words
An electronic power source as claimed in claim 1, wherein said battery is a nickel-cadmium battery.
Claim 8
Dependent Claim
16 words
An electronic power source as claimed in claim 1, wherein said battery is a lead battery.
Claim 9
Dependent Claim
38 words
An electronic power source as claimed in claim 1, wherein said second means further comprises means for converting an alternating current voltage to a direct current voltage and said at least two voltages are constant direct current voltages.
References Cited (Backward Citations)
GB1496294A
Cited
US4384321A
Cited
US4441031A
Cited
US4386308A
Cited
US4451773A
Cited
US4488057A
Cited
US4714868A
Cited
US4575640A
Cited
GB2172416A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-04-23 | 1993-10-23 | 1994-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-23 | 1997-10-23 | 1998-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-23 | 2001-10-23 | 2002-04-24 | $7700.00 | Window Closed / Lapsed |