US 9,812,743 B2
Battery state monitoring circuit and battery device
Toshiyuki Koike, Chiba (JP); Kazuaki Sano, Chiba (JP); Atsushi Sakurai, Chiba (JP); and Hiroshi Mukainakano, Chiba (JP)
Assigned to SII SEMICONDUCTOR CORPORATION, Chiba (JP)
Filed by Seiko Instruments Inc., Chiba-shi, Chiba (JP)
Filed on Jun. 29, 2015, as Appl. No. 14/753,722.
Claims priority of application No. 2014-134401 (JP), filed on Jun. 30, 2014.
Prior Publication US 2015/0380774 A1, Dec. 31, 2015
Int. Cl. H02J 7/00 (2006.01); H02J 7/04 (2006.01); G01N 27/416 (2006.01); H01M 10/48 (2006.01); G01R 31/36 (2006.01); H01M 10/44 (2006.01)
CPC H01M 10/48 (2013.01) [G01R 31/3606 (2013.01); G01R 31/3662 (2013.01); H01M 10/44 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A battery state monitoring circuit for monitoring charge and discharge of a secondary battery, to thereby detect a state of charge of the secondary battery, the battery state monitoring circuit comprising:
a first terminal and a second terminal to which the secondary battery is connected;
an equivalent circuit of the secondary battery, the equivalent circuit comprising a first capacitor, a first resistor and a second resistor connected in series, and a second capacitor connected in parallel with the second resistor;
a sense resistor for detecting a charge and discharge current of the secondary battery;
a voltage-current converter including input terminals respectively connected to both ends of the sense resistor and an output terminal connected to the equivalent circuit, for measuring a voltage between the both ends of the sense resistor, to thereby cause a current depending on the charge and discharge current to flow to the equivalent circuit;
a first A/D converter for monitoring a voltage of the first terminal;
a second A/D converter for monitoring an open circuit voltage of the equivalent circuit; and
an arithmetic circuit for detecting the state of charge of the secondary battery based on an output signal of the first A/D converter and an output signal of the second A/D converter.