Charge and discharge control circuit and battery device

• US 9,647,465 B2
• Filed: 05/13/2015
• Issued: 05/09/2017
• Est. Priority Date: 05/14/2014
• Status: Active Grant

• Current Assignee: Ablic Inc. (MinebeaMitsumi Inc.)
• Original Assignee: SII Semiconductor Corporation
• Inventors: Ono, Takashi, Koike, Toshiyuki, Abe, Satoshi, Maetani, Fumihiko
• Primary Examiner(s): Ngo, Brian
• Application Number:
  US14/711,343
• Publication Number:
  US 20150333546A1
• Time in Patent Office: 727 Days
• Field of Search: 320236, 320127, 320128, 320134, 320135, 320137
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A short-circuit and overcurrent detecting circuit includes a reference voltage circuit including a constant current circuit, a first impedance element, a first transistor having a resistance value depending a voltage of a secondary battery, a second impedance element, and a second transistor having a resistance value depending the voltage of the secondary battery, which are connected in series. The reference voltage circuit outputs a first reference voltage from a node of the constant current circuit and the first impedance element, and outputs a second reference voltage from a node of the first transistor and the second impedance element. The short-circuit and overcurrent detecting circuit further includes: a first comparator circuit for comparing a voltage of an overcurrent detecting terminal with the first reference voltage; and a second comparator circuit for comparing the voltage of the overcurrent detecting terminal with the second reference voltage.

Claims

1. A charge and discharge control circuit, comprising:

a control circuit configured to detect a voltage and abnormality of a secondary battery; and

a short-circuit and overcurrent detecting circuit configured to detect an overcurrent and a short circuit based on a voltage of an overcurrent detecting terminal,

the short-circuit and overcurrent detecting circuit comprising;

a reference voltage circuit comprising a constant current circuit, a first impedance element connected to the constant current circuit, a first transistor including a drain connected to the first impedance element, and having a resistance value that is changed depending on the voltage of the secondary battery, a second impedance element connected to a source of the first transistor, and a second transistor including a drain connected to the second impedance element, and having a resistance value that is changed depending on the voltage of the secondary battery, the reference voltage circuit being configured to output a first reference voltage from a node of the constant current circuit and the first impedance element, and output a second reference voltage from a node of the first transistor and the second impedance element;

a first comparator circuit configured to compare the voltage of the overcurrent detecting terminal with the first reference voltage; and

a second comparator circuit configured to compare the voltage of the overcurrent detecting terminal with the second reference voltage.

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

wherein the first impedance element comprises a third transistor having a resistance value that is changed depending on the voltage of the secondary battery, and

wherein the second impedance element comprises a fourth transistor having a resistance value that is changed depending on the voltage of the secondary battery.

3. A battery device, comprising:

a secondary battery;

a charge and discharge control switch connected in a charge and discharge path of the secondary battery; and

the charge and discharge control circuit according to claim 1 configured to monitor a voltage of the secondary battery to control the charge and discharge control switch.

4. A battery device according to claim 3, further comprising a resistor connected in the charge and discharge path between the secondary battery and an external terminal, in which the charge and discharge control switch is connected.