Abstract: A voltage equalizer for a battery pack includes equalization switches provided corresponding to respective battery blocks that construct the battery pack, an equalization controlling unit, and an equalization diagnostic unit. The equalization diagnostic unit obtains an equalization control signal outputted from the equalization controlling unit, and an equalization detection signal detected at connection points of the equalization switches. Then, the equalization diagnostic unit compares the equalization control signal and the equalization detection signal, and diagnoses whether or not equalization processing in each of the battery blocks is executed in conformity based on a result of the comparison.

Abstract: A voltage detection device connects the positive electrodes of unit cells (BT1 to BT4) and terminals (T1 to T4) of a multiplexer (12) via connection lines (L1 to L4), respectively, and includes first switches (SW11 to SW14) between the connection lines and the unit cells. The voltage detection device connects first to fourth series-connected circuits (N1 to N4) to the respective connection lines to apply reference voltages to the connection lines. Subsequently, in a state where the first switches (SW11 to SW14) are turned off, reference voltages are applied to the respective connection lines and each of the reference voltages is selected by the multiplexer (12), level-shifted, and then digitized by an A/D converter (13). Based on the digitized voltages, the voltage detection device determines whether or not each of the multiplexer, level shifter, and A/D converter is nonconformity.

Abstract: An overheat protection device 10 that can perform the immediate resetting of the power cutoff control state or the power limit control state when the overheat state of the drive circuit (power MOSFET) is eliminated. A semiconductor switching apparatus and an intelligent power module 30 are also provided which use the overheat protection device 10. The overheat protection device 10 monitors the energized state of the drive circuit that drives the load 32; when it detects the overheat state of the drive circuit during the energized state, resets the energized state to limit or stop the driving of the load 32; holds the power limit control state or the power cutoff control state and monitors the overheat state in synchronism with the timing signal 102b having a predetermined cycle; and, when the absence of the overheat state is detected during the monitoring, generates the gate control signal 108a to reset the power limit control state or the power cutoff control state.

Abstract: To turn on or off semiconductor switches based on the current-duration product of a current flowing through them, the device of the present invention detects an ambient temperature of the harness and, based on thus detected ambient temperature, corrects a detected current value to compare the current-duration product of thus corrected current value to the threshold data, so that if that product value equals or exceeds that threshold data value, the semiconductor switches are turned off, thus avoiding the affection due to the heat from the engines or the semiconductor switches to effectively prevent the harness from fuming.

Abstract: A switching device which can reduce effectively noise that is generated from a charge pump used to generate a drive voltage for driving a plurality of semiconductor switches. In the switching device, the charge pump used to generate the drive voltage for operating the plurality of the semiconductor switches is shared in common by these semiconductor switches, and the plurality of the semiconductor switches can be driven by the drive voltage that is generated by the single charge pump. Due to this structure, the noise to be generated by the charge pump can be controlled to a minimum and the noise interfering into the power line can be removed by a single noise remove circuit, which makes it possible to simplify the structure of the switching device.