US5850136A
Expired / Lapsed
US
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Battery charger
Assignee: Integran Inc
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Filing: 1997-05-14
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Granted: 1998-12-15
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Expires: 2017-05-14
Abstract
Abstract A battery charger includes charge control circuits each connected in parallel with an associated one of serially-connected battery cells. Each charge control circuit includes a switching device; a comparator, having a hysteresis characteristic determined by two threshold voltages, e.g., a safe charging voltage and an optimum charging voltage, for comparing the battery voltage with one of the threshold voltages selected according to a changing direction of the battery voltage; a reference voltage source for generating a reference voltage corresponding to either one of the threshold values; and a driving circuit for receiving a comparator output to render the switching device conductive or cutoff. When the battery voltage falls between the threshold voltages, the switching device becomes conductive to cause a constant current to flow from the battery cell to the switching device.
Inventors
- 👤 Akira Kaneko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:25
CPC Classifications
H; H02; H02J; H02J7/00; H02J7/50; H02J7/52; H02J7/54; Y; Y02; Y02T; Y02T10/00; Y02T10/60; Y02T10/70
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
258 words
A battery charger comprising: a direct current power source adapted to be connected in series with a battery array which is comprised of serially-connected battery cells, said direct current power source being operable to output a predetermined maximum electric current when it performs a constant-current operation; and charge control circuits adapted to be connected in parallel with the serially-connected battery cells, respectively, each of said charge control circuits including: a switching device which is connected in parallel with an associated one of the battery cells when said charge control circuit is connected to the associated one battery cell; a comparator, having a hysteresis characteristic thereof determined by a first threshold voltage and a second threshold voltage lower than the first threshold voltage, for comparing a battery voltage across the associated one battery cell with one of the first and second threshold voltages which is selected depending on a direction in which the battery voltage changes and for generating a comparator output indicative of a result of the comparison between the battery voltage and the selected one threshold voltage, the first and second threshold voltages being determined according to charging characteristics of the serially-connected battery cells; a reference voltage source for generating a reference voltage corresponding to one of the first and second threshold voltages; and a driving circuit for selectively rendering the switching device conductive according to the comparator output, said driving circuit being operable to permit a constant current to flow from the associated one battery cell to said switching device when said switching device is conductive.
Claim 2
Dependent Claim
258 words
A battery charger comprising: a direct current power source adapted to be connected in series with a battery array which is comprised of serially-connected battery cells, said direct current power source being operable to output a predetermined maximum electric current when it performs a constant-current operation; and charge control circuits adapted to be connected in parallel with the serially-connected battery cells, respectively, each of said charge control circuits including: a switching device which is connected in parallel with an associated one of the battery cells when said charge control circuit is connected to the associated one battery cell; a comparator, having a hysteresis characteristic thereof determined by a first threshold voltage and a second threshold voltage lower than the first threshold voltage, for comparing a battery voltage across the associated one battery cell with one of the first and second threshold voltages which is selected depending on a direction in which the battery voltage changes and for generating a comparator output indicative of a result of the comparison between the battery voltage and the selected one threshold voltage, the first and second threshold voltages being determined according to charging characteristics of the serially-connected battery cells; a reference voltage source for generating a reference voltage corresponding to one of the first and second threshold voltages; and a driving circuit for selectively rendering the switching device conductive according to the comparator output, said driving circuit being operable to permit a constant current to flow from the associated one battery cell to said switching device when said switching device is conductive.
Claim 3
Dependent Claim
58 words
The battery charger according to claim 1, wherein said driving circuit of said each charge control circuit includes a negative feedback circuit having a resistor connected in series with said switching device, said resistor generating a voltage thereacross which is indicative of a current flowing through said switching device when said switching device is in a conduction state.
Claim 4
Dependent Claim
124 words
The battery charger according to claim 1, wherein said comparator of said each charge control circuit generates a comparator output of a first level until the battery voltage across the associated one battery cell reaches the first threshold voltage, generates a comparator output of a second level when the battery voltage rises and reaches the first threshold voltage, and generates a comparator output of the first level when the battery voltage drops and becomes lower than the second threshold voltage; and wherein said driving circuit of said each charge control circuit causes said switching device to be cutoff while the comparator output is at the second level and causes said switching device to be conductive while the comparator output is at the first level.
Claim 5
Dependent Claim
47 words
The battery charger according to claim 1, wherein said first threshold voltage is a voltage corresponding to a safe charging voltage of the associated one battery cell and the second threshold voltage is a voltage corresponding to an optimum charging voltage of the associated one battery cell.
Claim 6
Dependent Claim
55 words
The battery charger according to claim 1, wherein said each charge control circuit has a high internal resistance; and wherein a voltage applied from the direct current power source to said charge control circuits and also applied to the battery array is substantially equally divided between the charge control circuits and between the battery cells.
Claim 7
Dependent Claim
123 words
The battery charger according to claim 5, wherein said reference voltage source of said each charge control circuit generates the reference voltage based on a voltage which is applied from the direct current power source to said charge control circuits and then substantially equally divided between the charge control circuits; and wherein said each charge control circuit includes a voltage divider circuit for generating a voltage corresponding to the battery voltage across the associated one battery cell based on a voltage which is applied from the direct current power source to the battery array and then substantially equally divided between the battery cells, the thus generated voltage corresponding to the battery voltage across said associated one battery cell being supplied to said comparator.
Claim 8
Dependent Claim
68 words
The battery charger according to claim 1, wherein said each charge control circuit includes a current line through which said switching device is connected with said associated one battery cell and a power source line provided independently of and separately from the current line, said comparator and said driving circuit of said charge control circuit being connected with said associated one battery cell via said power source line.
Claim 9
Dependent Claim
34 words
The battery charger according to claim 1, wherein said each charge control circuit includes an abnormality detection circuit for monitoring occurrence of an abnormality including over-charging and over-discharging of said associated one battery cell.
Claim 10
Dependent Claim
211 words
A charge control circuit for a battery charger operable to charge a battery array comprised of serially-connected battery cells, said charge control circuit being adapted to be connected in parallel with an associated one of the battery cells, comprising: a switching device connected in parallel with the associated one battery cell; a comparator, having a hysteresis characteristic thereof determined by a first threshold voltage and a second threshold voltage lower than the first threshold voltage, for comparing a battery voltage across the associated one battery cell with one of the first and second threshold voltages which is selected depending on a direction in which the battery voltage changes and for generating a comparator output indicative of a result of the comparison between the battery voltage and the selected one threshold voltage, the first and second threshold voltages being determined according to charging characteristics of the serially-connected battery cells; a reference voltage source for generating a reference voltage corresponding to one of the first and second threshold voltages; and a driving circuit for selectively rendering the switching device conductive according to the comparator output, said driving circuit being operable to permit a constant current to flow from the associated one battery cell to said switching device when said switching device is conductive.
Claim 11
Dependent Claim
211 words
A charge control circuit for a battery charger operable to charge a battery array comprised of serially-connected battery cells, said charge control circuit being adapted to be connected in parallel with an associated one of the battery cells, comprising: a switching device connected in parallel with the associated one battery cell; a comparator, having a hysteresis characteristic thereof determined by a first threshold voltage and a second threshold voltage lower than the first threshold voltage, for comparing a battery voltage across the associated one battery cell with one of the first and second threshold voltages which is selected depending on a direction in which the battery voltage changes and for generating a comparator output indicative of a result of the comparison between the battery voltage and the selected one threshold voltage, the first and second threshold voltages being determined according to charging characteristics of the serially-connected battery cells; a reference voltage source for generating a reference voltage corresponding to one of the first and second threshold voltages; and a driving circuit for selectively rendering the switching device conductive according to the comparator output, said driving circuit being operable to permit a constant current to flow from the associated one battery cell to said switching device when said switching device is conductive.
Claim 12
Dependent Claim
53 words
The charge control circuit according to claim 9, wherein said driving circuit includes a negative feedback circuit having a resistor connected in series with said switching device, said resistor generating a voltage thereacross which is indicative of a current flowing through said switching device when said switching device is in a conduction state.
Claim 13
Dependent Claim
113 words
The charge control circuit according to claim 9, wherein said comparator generates a comparator output of a first level until the battery voltage across the associated one battery cell reaches the first threshold voltage, generates a comparator output of a second level when the battery voltage rises and reaches the first threshold voltage, and generates a comparator output of the first level when the battery voltage drops and becomes lower than the second threshold voltage; and wherein said driving circuit causes said switching device to be cutoff while the comparator output is at the second level and causes said switching device to be conductive while the comparator output is at the first level.
Claim 14
Dependent Claim
48 words
The charge control circuit according to claim 9, wherein said first threshold voltage is a voltage corresponding to a safe charging voltage of the associated one battery cell and the second threshold voltage is a voltage corresponding to an optimum charging voltage of the associated one battery cell.
Claim 15
Dependent Claim
60 words
The charge control circuit according to claim 9, further including: a current line through which said switching device is connected with said associated one battery cell; and a power source line provided independently of and separately from the current line, wherein said comparator and said driving circuit are connected with said associated one battery cell via said power source line.
Claim 16
Dependent Claim
30 words
The charge control circuit according to claim 9, further including: an abnormality detection circuit for monitoring occurrence of an abnormality including over-charging and over-discharging of said associated one battery cell.
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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) | 2001-12-14 | 2002-06-15 | 2002-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-14 | 2006-06-15 | 2006-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-14 | 2010-06-15 | 2010-12-15 | $7700.00 | Window Closed / Lapsed |