Battery control circuit responsive to external signal input

• US 8,957,638 B2
• Filed: 06/01/2012
• Issued: 02/17/2015
• Est. Priority Date: 06/09/2011
• Status: Active Grant

• Current Assignee: Ablic Inc. (Minebea Mitsumi, Inc.)
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Maetani, Fumihiko, Sano, Kazuaki, Koike, Toshiyuki, Ono, Takashi
• Primary Examiner(s): Levin, Naum B
• Application Number:
  US13/486,504
• Publication Number:
  US 20120313574A1
• Time in Patent Office: 991 Days
• Field of Search: 716/128, 716134-136
• US Class Current: 320/128
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

To solve a problem in that, even after a charge inhibition signal is input from an input terminal and a charge control transistor is turned OFF, if a load is connected between external terminals (EB+, EB−), a discharge current flows, and to solve another problem of power consumption of a charge/discharge control circuit (22), provided is a charge/discharge control circuit for controlling charge/discharge of a secondary battery, the charge/discharge control circuit including: a switch circuit for controlling a current that flows through the charge/discharge control circuit; a control circuit for controlling an operation of the switch circuit; and an input terminal to which a signal for controlling an operation of the charge/discharge control circuit is input from outside. In this way, when a signal is input to the input terminal from outside, the discharge current is interrupted, thereby reducing current consumption of the charge/discharge control circuit.

Claims

1. A charge/discharge control circuit for controlling charge/discharge of a secondary battery, the secondary battery connected to an external terminal by charge and discharge transistors, the charge/discharge control circuit comprising:

a switch circuit for controlling a current that flows through the charge/discharge control circuit;

a control circuit for controlling an operation of the switch circuit and the charge and discharge transistors;

an input terminal that receives an external signal for controlling an operation of the charge/discharge control circuit;

an external signal detection circuit connected to the input terminal; and

a charge/discharge monitoring circuit,

wherein the external signal detection circuit is connected to a positive terminal of the secondary battery via the switch circuit, and the charge/discharge monitoring circuit is connected to the positive terminal of the secondary battery via the switch circuit.

2. A charge/discharge control circuit according to claim 1,

wherein the switch circuit comprises a first switch circuit and a second switch circuit,

an output of the external signal detection circuit is connected to the control circuit,

a power supply of the external signal detection circuit is connected to a positive terminal of the secondary battery via the first switch circuit,

a power supply of the charge/discharge monitoring circuit is connected to the positive terminal of the secondary battery via the second switch circuit, and

when a signal is input to the input terminal, the control circuit outputs a signal for turning OFF the first switch circuit and the second switch circuit.

3. A battery device, comprising:

a chargeable/dischargeable secondary battery;

a charge/discharge control switch provided in a charge/discharge path of the chargeable/dischargeable secondary battery; and

the charge/discharge control circuit according to claim 2, for monitoring a voltage of the chargeable/dischargeable secondary battery and opening/closing the charge/discharge control switch to control charge/discharge of the chargeable/dischargeable secondary battery.

4. A battery device, comprising:

a chargeable/dischargeable secondary battery;

a charge/discharge control switch provided in a charge/discharge path of the chargeable/dischargeable secondary battery; and

the charge/discharge control circuit according to claim 1, for monitoring a voltage of the chargeable/dischargeable secondary battery and opening/closing the charge/discharge control switch to control charge/discharge of the chargeable/dischargeable secondary battery.