Abstract: A charge/discharge control circuit includes: an output terminal from which a cell-balance control signal is sent to each of the first and the second cell balance circuits; the first and the second voltage detection circuits; a control circuit configured to send the first and the second control signals in accordance with a detection signal received from at least one of the first and the second voltage detection circuits; and an output circuit configured to select one of a voltage of a power supply terminal, a voltage of an input terminal connected to each of a negative electrode of a first battery and a positive electrode of a second battery, and a voltage of a ground terminal in accordance with the first and second control signals, and send the selected voltage to the output terminal.

Abstract: A charge/discharge control circuit includes: an output terminal from which a cell-balance control signal is sent to each of the first and the second cell balance circuits; the first and the second voltage detection circuits; a control circuit configured to send the first and the second control signals in accordance with a detection signal received from at least one of the first and the second voltage detection circuits; and an output circuit configured to select one of a voltage of a power supply terminal, a voltage of an input terminal connected to each of a negative electrode of a first battery and a positive electrode of a second battery, and a voltage of a ground terminal in accordance with the first and second control signals, and send the selected voltage to the output terminal.

Abstract: A charge and discharge control circuit operates between a first and a second power supply voltage of the secondary battery, and is used in a cascade-connection to the second charge and discharge control circuit having the same configuration, and includes an output circuit and an output terminal for discharge control, an input circuit and an input terminal for discharge control, and a control circuit. The input circuit includes a first MOS transistor having a source terminal connected to the input terminal and a gate terminal for receiving the first power supply voltage, a second MOS transistor having a drain terminal and a gate terminal connected to a drain terminal of the first MOS transistor and a source terminal for receiving the second power supply voltage, and a third MOS transistor current-mirror-connected to the second MOS transistor and having a drain terminal for supplying a discharge control input signal.

Abstract: 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.

Abstract: A charge and discharge control circuit operates between a first and a second power supply voltage of the secondary battery, and is used in a cascade-connection to the second charge and discharge control circuit having the same configuration, and includes an output circuit and an output terminal for discharge control, an input circuit and an input terminal for discharge control, and a control circuit. The input circuit includes a first MOS transistor having a source terminal connected to the input terminal and a gate terminal for receiving the first power supply voltage, a second MOS transistor having a drain terminal and a gate terminal connected to a drain terminal of the first MOS transistor and a source terminal for receiving the second power supply voltage, and a third MOS transistor current-mirror-connected to the second MOS transistor and having a drain terminal for supplying a discharge control input signal.

Abstract: 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.

Abstract: Provided are a cell balance device with high cell balance performance and high cell balance speed and requiring no high voltage process, and a battery system including the cell balance devices. The cell balance device includes: three terminals to be connected to secondary batteries; one terminal to be connected to a voltage hold device; three switches provided between the three terminals and the one terminal; and a receiving terminal and a transmitting terminal for a synchronization signal. Alternatively, the cell balance device includes: four terminals to be connected to secondary batteries; two terminals to be connected to a voltage hold device; six switches provided between the four terminals and the two terminals; and a receiving terminal and a transmitting terminal for a synchronization signal. The battery system includes: a plurality of secondary batteries; a plurality of voltage hold devices; a plurality of cell balance devices; and a clock generation circuit.

Abstract: 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.

Abstract: There is provided a battery voltage detector circuit which uses a multiplexer system and which is capable of reducing the influence of the deviation of a detected voltage attributable to a parasitic capacitance, thus improving the accuracy of voltage detection. The battery voltage detector circuit that monitors the voltages of a plurality of batteries connected in series includes a flying capacitor, a multiplexer switch that sequentially connects the flying capacitor to the plurality of batteries, a voltage detecting unit that detects the voltage of the flying capacitor, a first reference potential detecting unit connected to one terminal of the flying capacitor, a second reference potential connecting unit connected to the other terminal of the flying capacitor, and a control circuit that controls the multiplexer switch, the first reference potential connecting unit and the second reference potential connecting unit.

Abstract: 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.

Abstract: Provided are a charge/discharge control circuit having a self-test function, which can dispense with a complicated test device, and a battery device. The battery device includes the charge/discharge control circuits each including a pull-up/pull-down circuit provided at a terminal to which a secondary battery is to be connected. When a self-test start signal is input so as to enter a self-test state, a self-test control circuit controls the pull-up/pull-down circuit, to thereby perform a test on a voltage detection circuit provided at the terminal to which the secondary battery is to be connected. When the self-test is finished, a self-test start signal is output to a next-stage charge/discharge control circuit, to thereby perform a test sequentially on the voltage detection circuits of the cascade-connected charge/discharge control circuits.

Abstract: 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.

Abstract: 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.

Abstract: 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?), a discharge current flows, and to solve another problem of power consumption of a charge/discharge control circuit (22), 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.

Abstract: Provided are a battery state monitoring circuit and a battery device, in which, even when one secondary battery becomes an overcharged state or an overdischarged state and then a voltage detection circuit operates, power is not consumed in only the one secondary battery. The battery state monitoring circuit includes: a plurality of voltage detection circuits which are provided for a plurality of secondary batteries, respectively, for detecting voltages of the plurality of secondary batteries; and a current bypass circuit provided in each of the plurality of voltage detection circuits, for allowing an operation current of the each of the plurality of voltage detection circuits to flow into a ground terminal. Therefore, when only one secondary battery becomes an overcharged state or an overdischarged state, the battery device operates so that the power of all the secondary batteries is consumed to prevent voltages between the secondary batteries from being unbalanced.

Abstract: There is provided a battery voltage detector circuit which uses a multiplexer system and which is capable of reducing the influence of the deviation of a detected voltage attributable to a parasitic capacitance, thus improving the accuracy of voltage detection. The battery voltage detector circuit that monitors the voltages of a plurality of batteries connected in series includes a flying capacitor, a multiplexer switch that sequentially connects the flying capacitor to the plurality of batteries, a voltage detecting unit that detects the voltage of the flying capacitor, a first reference potential detecting unit connected to one terminal of the flying capacitor, a second reference potential connecting unit connected to the other terminal of the flying capacitor, and a control circuit that controls the multiplexer switch, the first reference potential connecting unit and the second reference potential connecting unit.

Abstract: There are provided an overcurrent protection circuit which has a smaller circuit area, a charging and discharging control circuit, and a compact battery device. The charging and discharging control circuit includes an overcurrent detection circuit which monitors the voltage of an overcurrent detection resistor connected to an overcurrent detection terminal and which detects the flow of an overcurrent into a secondary battery, an overcurrent release circuit which monitors the voltage at a terminal to which a load is connected through a voltage step-down circuit connected to an overcurrent release terminal and which detects the removal of a load, and a clamping circuit connected to the overcurrent release terminal are provided. The voltage at the overcurrent release terminal is clamped by the voltage step-down circuit and the clamping circuit.

Abstract: Provided are a trimming circuit which does not need a dedicated terminal to which a current for cutting a fuse is input, and also a semiconductor device including the trimming circuit. The trimming circuit includes: an input terminal connected to a pad which is an external terminal of an internal circuit; a fuse provided between a power supply terminal and an output terminal; and a diode provided between the input terminal and the output terminal. The trimming circuit performs trimming by applying, to the pad, such a voltage that the diode is biased in the forward direction.

Abstract: Provided is a battery state monitoring circuit which detects that a voltage of a secondary battery has decreased abruptly because of an overcurrent, thereby being capable of protecting a battery device from an abrupt decrease in voltage of the secondary battery caused by the overcurrent. The battery state monitoring circuit includes a voltage comparator circuit and a power supply voltage detection circuit for detecting an abrupt decrease in power supply voltage, in which the voltage comparator circuit detects a normal overcurrent while the power supply voltage detection circuit detects the abrupt decrease in power supply voltage caused by load short-circuit.

Abstract: Provided are a battery state monitoring circuit with a small number of terminals and a battery device including the battery state monitoring circuit. An output of an overcharge detection circuit (12) is an open-drain output to a charge control terminal (18), and an input terminal of a voltage detection circuit (11) is connected to the charge control terminal (18), to thereby share a charger detection terminal and a charge control terminal.