US 12,394,995 B2
Internet of things device and battery power supply circuit thereof
Meng-Chien Chiang, Taipei (TW); and Yu Ping Hsu, Taipei (TW)
Assigned to Sercomm Corporation, Taipei (TW)
Filed by Sercomm Corporation, Taipei (TW)
Filed on Mar. 23, 2022, as Appl. No. 17/701,705.
Claims priority of application No. 202110806459.0 (CN), filed on Jul. 16, 2021.
Prior Publication US 2023/0020200 A1, Jan. 19, 2023
Int. Cl. H02J 7/00 (2006.01); H02H 1/00 (2006.01); H02H 3/06 (2006.01); H02H 3/24 (2006.01); H02H 7/18 (2006.01)
CPC H02J 7/00306 (2020.01) [H02H 1/0007 (2013.01); H02H 3/06 (2013.01); H02H 3/243 (2013.01); H02H 7/18 (2013.01); H02J 7/0031 (2013.01); H02J 7/0063 (2013.01); H02J 7/007182 (2020.01)] 10 Claims
OG exemplary drawing
 
1. A battery power supply circuit, comprising:
a battery;
a comparison circuit coupled to the battery and comparing a voltage of the battery with a predetermined over-discharge voltage to generate a comparison signal, wherein the comparison circuit comprises:
a voltage-dividing circuit coupled to the battery and dividing the voltage of the battery to generate a divided voltage; and
a three-terminal voltage regulator having a cathode terminal and an anode terminal respectively coupled to an output terminal of the comparison circuit and a ground, and having a reference terminal coupled to the divided voltage, wherein the three-terminal voltage regulator compares the divided voltage with a reference voltage, and generates the comparison signal at the output terminal of the comparison circuit; and
a battery protection circuit coupled to the battery and the comparison circuit, wherein the battery protection circuit comprises:
a first PNP transistor having an emitter terminal and a collector terminal respectively coupled to the battery and a load;
a first NPN transistor having a collector terminal and an emitter terminal respectively coupled to a base terminal of the first PNP transistor and the ground;
a second NPN transistor having a collector terminal and an emitter terminal respectively coupled to the collector terminal of the first PNP transistor and the ground, and having a base terminal coupled to the cathode terminal of the three-terminal voltage regulator; and
a power supply control circuit coupled to the base terminal of the first PNP transistor, and turning on the first PNP transistor according to a power supply control signal, wherein the first NPN transistor turns off the first PNP transistor in response to the voltage of the battery being less than the predetermined over-discharge voltage, wherein the battery protection circuit serves as a power supply path from the battery to the load and determines whether to cut off the power supply path according to the comparison signal, wherein the battery protection circuit cuts off the power supply path from the battery to the load when the voltage of the battery decreases from a value greater than the predetermined over-discharge voltage to a value less than the predetermined over-discharge voltage, but does not turn on the power supply path when the voltage of the battery increases from a value less than the predetermined over-discharge voltage to a value greater than the predetermined over-discharge voltage.