Seiko Instruments Inc

Sii Semiconductor Corporation

Ablic Inc.

Toshiyuki Koike

Kazuaki Sano

Atsushi Sakurai

Fumihiko Maetani

Takashi Ono

Satoshi Abe

Hiroshi Mukainakano

Kiyoshi Yoshikawa

Yoshihisa Tange

Wataru Sakamoto

Minoru Ariyama

Yoshihide Kanakubo

Shohei Tsukamoto

Muneharu Kawana

Provided is a battery monitoring system that has a high level of safety even under a state in which characteristics of a reference voltage circuit are deteriorated. The battery monitoring system has a configuration in which: a reference voltage of a first battery monitoring IC is monitored by a second battery monitoring IC; and the second battery monitoring IC outputs, when detecting that the reference voltage reaches a value falling outside a predetermined range, a signal indicating an abnormality of the reference voltage to the first battery monitoring IC, and the first battery monitoring IC stops monitoring of a battery when the signal indicating the abnormality of the reference voltage is input to the first battery monitoring IC.

Battery monitoring system

Provided is a battery state monitoring circuit and a battery device capable of predicting a state of charge of a secondary battery with high accuracy. The battery state monitoring circuit includes a pseudo-equivalent circuit of the secondary battery, and causes a current flowing through a sense resistor to flow to the pseudo-equivalent circuit of the secondary battery, to thereby measure a pseudo-open circuit voltage of the secondary battery.

Battery state monitoring circuit and battery device

There is provided a battery device in which the accuracy of an over-current detection current value is high to have high safety. In a charging/discharging control circuit, a reference voltage circuit of an over-current detection circuit is configured to include a constant current circuit, a resistor, and a transistor having a resistance value that varies with a voltage of a secondary cell, that are connected to both ends of the secondary cell, and outputs, as a reference voltage, a voltage that is generated due to the flowing of a current of the constant current circuit to the resistor and the transistor.

Charging/discharging control circuit, charging/discharging control device, and battery device

Provided is a highly safe battery device in which the accuracy of an overcurrent detection current value and a short-circuit current value is improved and current consumption is reduced. A short-circuit and overcurrent detecting circuit includes: a reference voltage circuit configured to output a reference voltage generated when a constant current flows through an impedance element and a transistor having a resistance value that is changed depending on a voltage of a secondary battery; a first comparator circuit configured to compare a voltage of an overcurrent detecting terminal with the reference voltage; and a second comparator circuit configured to compare a voltage based on the voltage of the overcurrent detecting terminal with the reference voltage.

Charge and discharge control circuit and battery device

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.

Provided is a battery device with high convenience, which is capable of setting overcurrent release impedance to be low. The battery device includes: a first comparator circuit for detecting an overcurrent based on a first reference voltage; and a second comparator circuit for outputting an overcurrent release voltage control signal based on a second reference voltage that is higher than the first reference voltage.

Provided is a reference voltage circuit capable of forming optimal circuits for various modes of an electronic device. The reference voltage circuit includes, between respective transistors forming the reference voltage circuit and between the transistors and a power supply terminal, switching elements configured to switch a circuit configuration of the reference voltage circuit.

Reference voltage circuit and electronic device

Provided is a charge and discharge control circuit and a battery device which ensure high safety, even when a charger is reversely connected. The charge and discharge control circuit includes a consumption current increase circuit for supplying a current from a power supply terminal to a ground terminal, the consumption current increase circuit including a switch circuit configured to be turned on in response to a detection signal from a charger reverse connection detection circuit, which indicates that a charger is reversely connected.

The level shifter circuit includes: a first transistor including a gate connected to an input terminal of the level shifter circuit and a source connected to a first power supply terminal; a first resistor including one terminal connected to the input terminal of the level shifter circuit; a second transistor including a gate connected to another terminal of the first resistor, a drain connected to a drain of the first transistor, and a source connected to a terminal for inputting the voltage subjected to the level conversion; and a third transistor including a gate and a drain connected to the another terminal of the first resistor, and a source connected to the terminal for inputting the voltage subjected to the level conversion. Further, the battery device includes the charge/discharge control circuit.

Charge/discharge control circuit and battery device

Provided is a battery device with high safety, which has improved accuracy of overcurrent detection. In the battery device, an overcurrent detection terminal of a battery state monitoring circuit is connected to a node between a discharge control switch and a charge control switch via a resistor.

Battery device

Provided is a battery device for controlling charge/discharge of a secondary battery by a single bidirectionally conductive field effect transistor, a charge/discharge control circuit with which a leakage current of the bidirectionally conductive field effect transistor is reduced to perform stable operation. The charge/discharge control circuit includes: a switch circuit for controlling a gate of the bidirectionally conductive field effect transistor based on an output of a control circuit for controlling the charge/discharge of the secondary battery; and two MOS transistors for preventing back-flow of a charge current and a discharge current. The first MOS transistor has a drain and a back gate which are connected to each other, and a source connected to a drain of the bidirectionally conductive field effect transistor. The second MOS transistor has a drain and a back gate which are connected to each other, and a source connected to a source of the bidirectionally conductive field effect transistor.

Provided is a battery device including, in a charge/discharge protection circuit for controlling charge/discharge of a secondary battery by a single bidirectionally conductive field effect transistor, a charge/discharge control circuit with which the number of elements to be used is reduced to reduce the layout area. The charge/discharge control circuit includes a switch circuit for controlling a gate of the bidirectionally conductive field effect transistor based on an output of a control circuit for controlling the charge/discharge of the secondary battery, the switch circuit including a first terminal connected to a back gate of the bidirectionally conductive field effect transistor.

To solve a problem in that, even after a charge inhibition signal is input from an input terminal and a charge control transistor is turned OFF, if a load is connected between external terminals (EB+, EB&#x2212;), a discharge current flows, and to solve another problem of power consumption of a charge/discharge control circuit (), provided is a charge/discharge control circuit for controlling charge/discharge of a secondary battery, the charge/discharge control circuit including: a switch circuit for controlling a current that flows through the charge/discharge control circuit; a control circuit for controlling an operation of the switch circuit; and an input terminal to which a signal for controlling an operation of the charge/discharge control circuit is input from outside. In this way, when a signal is input to the input terminal from outside, the discharge current is interrupted, thereby reducing current consumption of the charge/discharge control circuit.

Battery control circuit responsive to external signal input

There is provided a charge/discharge control circuit and a battery assembly including an accurate overcurrent protecting circuit with low consumption current characteristics. The charge/discharge control circuit comprises a current protecting circuit including: a reference voltage circuit having a reference transistor for detecting overcurrent flowing through a control transistor to turn it on, and a constant current circuit; and a comparison circuit for comparing voltage on the reference voltage circuit with voltage generated by overcurrent flowing through the control transistor, wherein when no overcurrent flows, the electric current flowing through the reference voltage circuit is interrupted to reduce power consumption.

Charge/discharge control circuit and battery assembly

Provided are a battery state monitoring circuit and a battery device that are capable of reliably controlling charge by a charger even if a voltage of a secondary battery drops to around 0 V. In the battery device provided with the battery state monitoring circuit, respective gate voltages of a P-type metal oxide semiconductor (PMOS) transistor and an N-type metal oxide semiconductor (NMOS) transistor, which together form a voltage detection circuit for detecting a voltage of around 0 V of the secondary battery, are applied by a voltage dividing resistor circuit that is connected across terminals of the secondary battery.

Growing community of inventors

Chiba, Japan

Toshiyuki Koike