Denso Corporation

Satoshi Sobue

Tomohisa Yamamoto

Hiroyuki Ban

Tomomichi Mizoguchi

Shigenori Mori

The battery fault determination apparatus includes battery monitor sections connected in a daisy chain, each of which is provided for a corresponding one of unit batteries each including battery cells connected in series to monitor the battery cells and output an output signal indicative of a monitoring result, and a control section configured to output a control signal to the battery monitor sections. The control signal and the output signal are cascaded through the battery monitor sections causing each battery monitor section to perform a state change between a state to monitor overcharge of the battery cells and a state to monitor wire breakage. Each battery monitor section is configured to receive the control signal from the immediately upstream-side battery monitor section, make a detection whether the state change has been performed correctly, and output the output signal including a detection result to the immediately downstream-side battery monitor section.

Battery fault detection apparatus

A semiconductor integrated circuit device formed by a trench dielectric isolation technique has input terminals connected to positive and negative terminals of secondary cells of an assembled battery and includes monitor circuits for respectively monitoring cell voltages of the cells. Each monitor circuit includes a cell voltage detection circuit, a reference voltage generation circuit, and a comparison circuit. The cell voltage detection circuit divides a voltage between the input terminals connected to the positive and negative terminals of a corresponding cell and detects the cell voltage based on the divided voltage. The reference voltage generation circuit generates a reference voltage from the cell voltage. The comparison circuit is powered by the cell voltage of the corresponding cell and compares the divided voltage with the reference voltage.

Semiconductor integrated circuit device for monitoring cell voltages

A current mirror circuit includes transistors having bases coupled together and emitters connected to a voltage line. The current mirror circuit further includes a zener diode having an anode connected to the bases and a cathode connected to the voltage line. When a base potential of the transistors decreases, a reverse current of the zener diode increases. Therefore, the zener diode has a resistance and acts as a resistor to clamp the base potential of the transistors. A layout area of the zener diode is much smaller than that of the resistor having a resistance equal to that of the zener diode. The current mirror circuit achieves reduced chip size by using the zener diode instead of the resistor.

Current mirror circuit for reducing chip size

A current mirror circuit includes a pair of first and second transistors having bases connected together and emitters connected to a power line, a resistor connected between the bases of the first and second transistors and the power line, a third transistor for providing base currents of the first and second transistors and a resistor current flowing through the resistor, and a current compensation circuit that adds a compensation current to an input current to the first transistor. The amount of the compensation current is approximately equal to that of the resistor current divided by a current gain of the third transistor. Thus, the compensation current compensates the difference between a collector current of the first transistor and the input current.

Current mirror circuit and constant current circuit having the same

In a combined battery pack of a plurality of battery cells, a comparison circuit compares a voltage appearing at a common connection point between two adjacent battery cells with a reference voltage. Based on a result of the comparison, an electric discharging operation of an electric discharging circuit connected between both terminals of each of the battery cells is carried out. The comparison circuit is driven to operate with a power supply voltage appearing between a positive-side terminal of a battery cell provided on a higher-potential side of a common connection point and the negative-side terminal of the battery cell provided on a lower-potential side of the common connection point.

Cell voltage equalization apparatus for combined battery pack including circuit driven by power supplied by the combined battery pack

A battery ECU controls a main battery composed of a plurality of battery cells connected to each other in series. The battery cells are grouped into cell blocks each having a cell-block monitor circuit. A control unit controls charging/discharging processes on the basis of signals output by the cell-block monitor circuit. A signal output by a cell-block monitor circuit on a high-voltage side turns on a transistor for propagating a signal to a cell-block monitor circuit on a middle-voltage side. In the cell-block monitor circuit on a middle-voltage side, the propagated signal turns on another transistor for further propagating a signal to a cell-block monitor circuit on a low-voltage side. In the cell-block monitor circuit on a low-voltage side, the propagated signal turns on a further transistor for outputting a signal to a control unit.

Circuit system for a battery electronic control unit

A comparator includes a differential amplification circuit having differential input transistors and load transistors, an output transistor for outputting an output value of the comparator, a diode having a cathode connected to a ground, a current output circuit, a resistor connected between an anode of the diode and the bases of the load transistors. When the output transistor is in the OFF state, the diode clamps the voltage of the resistor to a forward voltage so that no current flows through the resistor. When the output transistor is in the ON state, the resistor has a slight voltage so that a slight current flows through the resistor. Thus, a threshold voltage of the comparator has a slight hysteresis without increase in resistance of the resistor.

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Nukata-gun, Japan

Satoshi Sobue