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EP0319020A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Over-discharge protection circuit

Assignee: Fujitsu Ltd
•
Filing: 1988-12-02
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Granted: —
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Expires: 2008-12-02
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Abstract

Abstract An over-discharge protection circuit included in a charge circuit in a portable apparatus having a portable portion and a body, the portable portion and body being interconnected by two charging terminals of the body and two terminals of the portable portion when the portable portion is placed on the body; the over-discharge protection circuit comprises: first resistor connected across a battery charger for detecting a discharge current when a power source of the battery charger is accidentally turned OFF during a charge of the battery; a switching circuit connected between a load and a battery for disconnecting the load and battery when the power source of the battery charger is accidentally turned OFF during a charge of the battery; a switch control circuit connected to the switching circuit through a third resistor for turning the switching circuit ON/OFF; a second resistor connected between the switching circuit and the switch control circuit for controlling a flow of a charge current to the switch control circuit; and a diode connected between the switch control circuit and the first resistor for allowing a flow of the discharge current to the first resistor when the power source of the battery charger is accidentally turned OFF during a charge of the battery.

Inventors

  • 👤 Akio Nakanishi
  • 👤 Ken-Ichi Ikegaya
  • 👤 Takao Naito
  • 👤 Yukio Sejima
  • 👤 Koji Matsushima

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-31 23:16
CPC Classifications
H; H02; H02J; H02J7/00; H02J7/60; H02J7/663

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 210 words
An over-discharge protection circuit included in a charge circuit in a portable apparatus having a portable portion and a body, said portable portion and said body being interconnected by two charging terminals of said body and two terminals of said portable portion when said portable portion is placed on said body, said over-discharge protection circuit comprising: a first resistor connected across a battery charger for detecting a discharge current when a power source of said battery charger is accidentally turned OFF while a battery is being charged: a switching means connected between a load and said battery for disconnecting said load and said battery when said power source of said battery charger is accidentally turned OFF during a charge of said battery; a switch control means connected to said switching means through a third resistor for turning said switching means ON/OFF; a second resistor connected between said switching means and said switch control means for controlling a flow of a charge current to said switch control means; and a diode connected between said switch control means and said first resistor for allowing a flow of said discharge current to said first resistor when said power source of said battery charger is accidentally turned OFF during a charge of said battery.
Claim 2
Dependent Claim 210 words
An over-discharge protection circuit included in a charge circuit in a portable apparatus having a portable portion and a body, said portable portion and said body being interconnected by two charging terminals of said body and two terminals of said portable portion when said portable portion is placed on said body, said over-discharge protection circuit comprising: a first resistor connected across a battery charger for detecting a discharge current when a power source of said battery charger is accidentally turned OFF while a battery is being charged: a switching means connected between a load and said battery for disconnecting said load and said battery when said power source of said battery charger is accidentally turned OFF during a charge of said battery; a switch control means connected to said switching means through a third resistor for turning said switching means ON/OFF; a second resistor connected between said switching means and said switch control means for controlling a flow of a charge current to said switch control means; and a diode connected between said switch control means and said first resistor for allowing a flow of said discharge current to said first resistor when said power source of said battery charger is accidentally turned OFF during a charge of said battery.
Claim 3
Dependent Claim 18 words
An over-discharge protection circuit as claimed in claim 1, wherein said switching means comprises a PNP type transistor.
Claim 4
Dependent Claim 21 words
An over-discharge protection circuit as claimed in claim 1, wherein said switch control circuit comprises two transistors forming a Darlington connection.
Claim 5
Dependent Claim 17 words
An over-discharge protection circuit as claimed in claim 1, wherein said switch control circuit comprises a comparator.

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