EP0588615A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Battery protection circuits
Assignee: Sony Corp
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Filing: 1993-09-15
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Granted: —
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Expires: 2013-09-15
Abstract
Abstract A battery protection circuit has a condition detecting circuit which detects a voltage across a secondary cell or cells and compares the detected voltage with a reference voltage to detect an overdischarged condition or an overcharged condition of the secondary cell or cells. A control unit controls a first switching element for cutting off a discharging current and a second switching element for cutting off a charging current based on a detected condition of the secondary cell or cells. A third switch element cuts off electric power supplied to the condition detecting circuit. The third switch element is rendered nonconductive when the overdischarged condition is detected by the condition detecting circuit.
Inventors
- 👤 Yasuhito c/o Intellectual Property Div. Eguchi
- 👤 Hitoshi c/o Intellectual Property Div. Okada
- 👤 Kanji c/o Intellectual Property Div. Murano
- 👤 Akira C/O Sony Energytec Inc. Sanpei
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 09:55
CPC Classifications
H; H02; H02J; H02J7/00; H02J7/60; H02J7/663; H02H; H02H7/00; H02H7/18; H02J7/50; H02J7/52; H02J7/56; H02J7/61; H02J7/63
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
119 words
A battery protection circuit for a secondary cell, the circuit comprising: condition detecting means for detecting a voltage across a secondary cell and comparing the detected voltage with a reference voltage to detect an overdischarged condition or an overcharged condition of said secondary cell; first switch means for cutting off a discharging current; second switch means for cutting off a charging current; control means for controlling said first and second switch means based on a detected condition detected by said condition detecting means; third switch means for cutting off electric power supplied to said condition detecting means; and power-down mode means for rendering said third switch means nonconductive when the overdischarged condition is detected by said condition detecting means.
Claim 2
Dependent Claim
40 words
A battery protection circuit according to claim 1, further comprising power-down mode canceling means for restoring said third switch means from a nonconductive condition to a conductive condition when the secondary cell starts being charged again from the overdischarged condition.
Claim 3
Dependent Claim
53 words
A battery protection circuit according to claim 2, for a plurality of secondary cells connected in series with each other, wherein said power-down mode means comprises means for rendering said third switch means nonconductive when the overdischarged condition of one or all of said secondary cells is detected by said condition detecting means.
Claim 4
Dependent Claim
40 words
A battery protection circuit according to claim 3, further comprising power-down mode inhibiting means for holding said third switch means conductive if either one of said secondary cells is in the overcharged condition as detected by said condition detecting means.
Claim 5
Dependent Claim
48 words
A battery protection circuit according to claim 1, further comprising voltage drop preventing means for holding said third switch means conductive thereby to prevent the voltage detected across said secondary cell from dropping below a detected overdischarged voltage if an instantaneous large current flows through said secondary cell.
Claim 6
Dependent Claim
48 words
A battery protection circuit according to claim 3, further comprising voltage drop preventing means for holding said third switch means conductive thereby to prevent the voltage detected across said secondary cells from dropping below a detected overdischarged voltage if an instantaneous large current flows through said secondary cells.
Claim 7
Dependent Claim
30 words
A battery protection circuit according to claim 3, further comprising means for restoring a capacity balance of the secondary cells if the secondary cells are out of the capacity balance.
Claim 8
Dependent Claim
28 words
A battery protection circuit according to claim 1, further comprising charging and discharging terminals which are connected to said secondary cell and which are separate from each other.
Claim 9
Dependent Claim
28 words
A battery protection circuit according to claim 3, further comprising charging and discharging terminals which are connected to said secondary cells and which are separate from each other.
Claim 10
Dependent Claim
177 words
A battery protection circuit for a secondary cell, the circuit comprising: condition detecting means for detecting a voltage across a secondary cell and comparing the detected voltage with a reference voltage to detect an overdischarged condition or an overcharged condition of said secondary cell; first switch means for cutting off a discharging current; second switch means for cutting off a charging current; control means for controlling said first and second switch means based on a detected condition detected by said condition detecting means; power-down switch means for cutting off electric power supplied to said condition detecting means; power-down mode means for rendering said power-down switch means nonconductive when the overdischarged condition is detected by said condition detecting means; and power-down mode canceling means for restoring said power-down switch means from a nonconductive condition to a conductive condition when the secondary cell starts being charged again from the overdischarged condition; said power-down mode canceling means comprising means for restoring said power-down switch means to the conductive condition after the voltage across said secondary cell exceeds a predetermined voltage.
Claim 11
Dependent Claim
52 words
A battery protection circuit according to claim 10, for a plurality of secondary cells connected in series with each other, wherein said power-down mode means comprises means for rendering said power-down means nonconductive when the overdischarged condition of one or all of said secondary cells is detected by said condition detecting means.
Claim 12
Dependent Claim
52 words
A battery protection circuit according to claim 11, wherein said control means comprises means for holding said power-down switch means conductive for a first interval of time if an instantaneous large current flows through said secondary cells for a second interval of time which is shorter than said first interval of time.
Claim 13
Dependent Claim
40 words
A battery protection circuit according to claim 11, further comprising power-down mode inhibiting means for holding said third switch means conductive if either one of said secondary cells is in the overcharged condition as detected by said condition detecting means.
Claim 14
Dependent Claim
38 words
A battery protection circuit according to claim 10, further comprising forced charging means for forcibly rendering said secondary cell chargeable if said power-down switch means is nonconductive and the voltage across said secondary cell is substantially 0 V.
Claim 15
Dependent Claim
38 words
A battery protection circuit according to claim 11, further comprising forced charging means for forcibly rendering said secondary cells chargeable if said power-down switch means is nonconductive and the voltage across said secondary cells is substantially 0 V.
Claim 16
Dependent Claim
28 words
A battery protection circuit according to claim 10, further comprising charging and discharging terminals which are connected to said secondary cell and which are separate from each other.
Claim 17
Dependent Claim
28 words
A battery protection circuit according to claim 11, further comprising charging and discharging terminals which are connected to said secondary cells and which are separate from each other.
References Cited (Backward Citations)
No citation records indexed.
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