| 摘要 |
PURPOSE: A charge/discharge protection circuit for a rechargeable battery is provided to economically realize the protection circuit in standard sub-micro technology having a low break-down voltage, while requiring little real estate on an IC chip. CONSTITUTION: A charge/discharge protection circuit comprises a short-circuit switch(20) coupled in series with a fusible link(2) across the terminals of a rechargeable battery, wherein one end of the fusible link is connected to one of the battery terminals, and the short-circuit switch leads to the guarantied destruction of the fusible link when closed, thereby protecting the rechargeable battery from a dangerous current over-charge, a load current switch having an end coupled to the junction of the fusible link and the short-circuit switch the other end in communication with a first charge/discharge terminal of the protection circuit, wherein the load current switch connects or disconnects the first charge/discharge terminal from the rechargeable battery, a second charge/discharge terminal of the protection circuit coupled to the other end of the battery terminal, and a control logic coupled between the battery terminals and in communication with the first charge/discharge terminal, wherein the control logic protects the battery and the first and the second charge/discharge terminals from over/under-voltage conditions. The control logic opens or closes the load current switch depending on the magnitude of the potential at the first and the second charge/discharge terminals of the protection circuit. The control logic includes an over-voltage detector which closes the short-circuit switch when reaching a predetermined voltage limit which depends on the electric strength of the protection circuit.
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