Battery protecting circuit, battery protecting device, and battery pack

• US 9,035,620 B2
• Filed: 12/27/2012
• Issued: 05/19/2015
• Est. Priority Date: 01/23/2012
• Status: Active Grant

• Current Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Original Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Inventors: Kimura, Daisuke
• Primary Examiner(s): Nguyen, Nha
• Application Number:
  US13/727,893
• Publication Number:
  US 20130187615A1
• Time in Patent Office: 873 Days
• US Class Current: 320/134
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/00309 Overheat or overtemperature protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence

Abstract

A disclosed battery protecting circuit includes a battery protecting IC powered by a voltage of a secondary battery; another battery protecting IC powered by a voltage of another secondary battery connected to the secondary battery in series; and a constant voltage output unit which receives a maximum voltage obtained by adding voltages of the secondary battery and the other secondary battery in series and outputs a constant voltage upon receipt of a control signal from an output terminal of the battery protecting IC or the other battery protecting IC.

Claims

1. A battery protecting circuit comprising:

a first battery protecting IC powered by a voltage of a first secondary battery;

a second battery protecting IC powered by a voltage of a second secondary battery connected to the first secondary battery in series; and

a constant voltage output unit which receives a maximum voltage obtained by adding voltages of the first secondary battery and the second secondary battery in series and outputs a constant voltage upon receipt of a control signal from an output terminal of the first battery protecting IC or the second battery protecting IC, said constant voltage output unit including a transistor which receives the maximum voltage and generates the constant voltage in conformity with the control signal.

2. The battery protecting circuit according to claim 1,

wherein the constant voltage output unit includes the transistor provided for each of the control signals.

3. The battery protecting circuit according to claim 1,

wherein the constant voltage output unit stops outputting the constant voltage when the constant voltage exceeds the predetermined value.

4. The battery protecting circuit according to claim 1, further comprising:

a load powered by the constant voltage.

5. The battery protecting circuit according to claim 4,

wherein the load includes a temperature detecting unit.

6. The battery protecting circuit according to claim 5,

wherein the first battery protecting IC and the second battery protecting IC protect the first secondary battery and the second secondary battery using a temperature detected by the temperature detecting unit.

7. A battery protecting device comprising:

a battery protecting circuit according to claim 1; and

a shutoff unit for shutting off a current flowing through the first secondary battery and the second secondary battery in conformity with control outputs from the battery protecting circuit.

8. A battery pack comprising:

the battery protecting device according to claim 7; and

the first secondary battery; and

the second secondary battery.