Mitsumi Electric Company Ltd.

Junji Takeshita

Takashi Takeda

Daisuke Suzuki

Takeshi Yamaguchi

Yoshihiro Motoichi

Gentaro Kurokawa

Kouichirou Sakamoto

Yohei Watanabe

Hiroki Matsuda

Masayuki Suzuki

Yuji Yamanaka

Koji Yano

Yukihiro Terada

Takatoshi Itagaki

Daisuke Kimura

Tomomitsu Ohara

Ryota Kageyama

Tomiyuki Nagai

Naoshi Tokuda

Koichi Murano

Yasuhiro Tokumaru

Keisuke Yamazato

Kouhei Shibata

Koichiro Sakamoto

A secondary battery protection apparatus includes a temperature sensitive element and a secondary battery protection circuit with a first terminal coupled to an external device and the temperature sensitive element to control charge and discharge using a switching circuit to protect a secondary battery from temperature, and a conversion circuit of the secondary battery protection circuit is controlled such that a first input of a comparison circuit to compare a voltage against a threshold is electrically coupled to the first terminal of the secondary battery protection circuit, the voltage corresponding to a change in temperature of the secondary battery.

Secondary battery protection apparatus and battery pack including temperature sensitive element

A secondary battery protection circuit for controlling charge and discharge using a switching circuit to protect a secondary battery from temperature is provided. The switching circuit is configured to be provided in a charge-and-discharge path between the secondary battery and an external device. The secondary battery protection circuit includes a detection terminal configured to be electrically connected, via a resistor, to between the switching circuit and the external device. The secondary battery protection circuit includes a first terminal configured to be electrically connected to a temperature detection terminal of the external device. The secondary battery protection circuit includes a second terminal to which a temperature sensitive element is configured to be electrically connected, the temperature sensitive element having a characteristic value varying in accordance with a change in temperature of the secondary battery.

Secondary battery protection circuit, secondary battery protection apparatus, battery pack and temperature detection circuit

A secondary-battery protection circuit is configured to, in response to detecting that a first switching circuit is turned on and a second switching circuit is turned on, supply a first output voltage to a first load between a first terminal and a second terminal; and supply a third output voltage to a second load between the first terminal and a third terminal, the third output voltage indicating the sum of the first output voltage and a second output voltage, the second output voltage corresponding to a voltage across a second secondary battery. In response to detecting that the first switching circuit is turned off and the second switching circuit is turned on, the secondary-battery protection circuit is configured to stop supplying the first output voltage to the first load; and stop supplying the third output voltage via the first terminal and the third terminal.

Secondary-battery protection circuit and battery pack

A battery protection circuit for protecting a secondary battery, the battery protection circuit not having a CPU, includes a non-volatile memory into which characteristics data determining protective characteristics of the battery protection circuit are writable; and a protection operation circuit which performs a protection operation of the secondary battery based on the characteristics data read out of the non-volatile memory.

Battery protection circuit, battery protection apparatus, and battery pack

A secondary protection IC is connected in parallel with a rechargeable battery and controls the charge and discharge of the rechargeable battery separately from a primary protection IC. The secondary protection IC includes a detection circuit that detects an overcharge or overdischarge of the rechargeable battery, a regulator that stabilizes the voltage of the rechargeable battery and outputs the stabilized voltage to the outside of the rechargeable battery, and a control terminal that controls the regulator with a control signal. Each of the detection circuit and the regulator performs a normal operation or stops operating based on the voltage of the rechargeable battery and the control signal.

Secondary protection IC, method of controlling secondary protection IC, protection module, and battery pack

In a battery pack, an overcharge detecting circuit compares a voltage between a positive electrode and a negative electrode of a secondary battery with a threshold voltage to detect an overcharge of the secondary battery, and turns off a switching element. A series circuit including a thermistor and a resistor is arranged near the secondary battery and connected in parallel to the secondary battery. A comparator compares a voltage at a junction point of the thermistor and the resistor with a reference voltage corresponding to a predetermined temperature. In response to an output signal of the comparator, a changing unit changes the threshold voltage to a first value when a temperature of the secondary battery is below the predetermined temperature, and changes the threshold voltage to a second smaller value when the temperature of the secondary battery is above the predetermined temperature.

Overcharge detecting circuit and integrated circuit

A charge controller includes a charge control circuit that, when detecting that a charging power supply is connected, controls the charging transistor to apply the charge current; a first and second control switch element connected in series between one terminal of a secondary battery and an external terminal; and a protection circuit that, when the secondary battery is over-discharged, turns off the first control switch element to stop discharge current and when deeply discharged, turns off the second control switch element. The protection circuit sends a charge inhibit signal to the charge control circuit when the secondary battery is deeply discharged, and while receiving the charge inhibit signal, the charge control circuit keeps the charging transistor off to prevent the charge current from flowing even if detecting that the charging power supply is connected.

Charge controller with protective function and battery pack

A charge controller includes a charge control circuit which controls a charging transistor; and a protection circuit that, when the secondary battery is over-discharged, turns off the first control switch element to block discharge current and when the secondary battery is overcharged, turns off the second control switch element to prevent the charge current from flowing. The charge control circuit includes a function of control for applying constant charge current through the charging transistor until the voltage of the secondary battery reaches a predetermined value and switching to control for applying charge current at a constant voltage after the voltage of the secondary battery reaches the predetermined value, and a terminal voltage on the positive electrode side and a terminal voltage on the negative electrode side of the secondary battery are supplied as monitoring voltage to the charge control circuit.

Charge controller with protection function and battery pack

A protection circuit includes a detector to detect an overcharging or an excessive discharging of a battery, from a voltage of a power terminal coupled to the battery, a controller to generate a control signal to stop the charging or the discharging of the battery when a detection of the overcharging or the excessive discharging is continuously detected by the detector for a predetermined time, and a current varying circuit to vary a current flowing through the power terminal only for a certain time when the detector detects the overcharging or the excessive discharging of the battery.

Protection circuit and battery pack having current varying circuit to vary current flowing through power terminal

A charge control circuit equipped with a function of controlling a charging current to be supplied to a secondary battery, comprises: a detecting unit for monitoring a temperature; and a charge control unit for controlling so as to break the charging current when the monitored temperature rises to a temperature equal to or more than a predetermined set temperature, decrease the charging current as the monitored temperature becomes higher when the monitored temperature is in a predetermined temperature range lower than the set temperature, flow the charging current having a predetermined current value in a state where the monitored temperature is lower than a lower limit temperature of the temperature range, or flow the charging current having a current value smaller than the current value when the monitored temperature is within a range of from an upper limit temperature of the temperature range to the set temperature.

Charge control circuit and charge controlling semiconductor integrated circuit

Battery pack

A battery pack including a protection circuit configured to detect over-charge, over-discharge and over-current of a rechargeable battery to turn off a switch element, the switch element provided at a wire provided between the rechargeable battery and a load circuit or a charging device; a series circuit of a thermistor and a resistor, the series circuit provided in parallel to the rechargeable battery, the thermistor thermally connected to the rechargeable battery; and an abnormal temperature detection unit provided in the protection circuit, wherein the abnormal temperature detection unit operates the switch to be in an off state when the temperature of the rechargeable battery is higher than a predetermined temperature, and when a voltage of the wire is higher than a threshold voltage of a forward drop voltage of a body diode in the switch, the abnormal temperature detection unit operates the switch to be in an on state.

A battery pack has first through third external terminals connected to positive and negative power supply terminals and a voltage detection terminal, respectively. A secondary battery is connected between the first external terminal and the third external terminal. A protection circuit controls ON/OFF of first and second switching elements provided on a wiring between the secondary battery and a load or a charge device by detecting an overcharge, an overdischarge and an overcurrent of the secondary battery. A first thermistor is connected between the second external terminal and the third external terminal. A series circuit containing a second thermistor and a resistor is provided in parallel to the secondary battery. A third switching element is connected between the second external terminal and the third external terminal. The protection circuit turns on the third switching element and short-circuits between the second external terminal and the third external terminal when a detection is made by the second thermistor that a temperature of the secondary battery exceeds a predetermined temperature.

Battery pack having protection circuit for secondary battery

A DC-DC converter includes: an inductance element and a rectifier element connected in series between a voltage input terminal to accept input direct current voltage and a first output terminal; a switching element connected between a connection node of the inductance element and the rectifier element and a reference potential point; and a controlling circuit to form a signal to control on/off of the switching element. The controlling circuit controls on/off of the switching element to control current through the inductance element, and a voltage applied to the voltage input terminal to accept the input direct current voltage is output via a second output terminal as a reference potential of a circuit at a latter stage, so that an output voltage is controllable from a lower to higher voltage than the input direct current voltage without switching step-up and step-down operations.

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Atsugi, Japan

Junji Takeshita