| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching element drive device with which it is possible to detect a bipolar electric current with high accuracy while suppressing the consumption of electric power.SOLUTION: One terminal of a current detection resistor 18 is connected to the source of a sense FET 6, the positive terminal of a first power supply circuit 17 is connected to a battery 8, and a voltage output terminal is connected to a terminal PGND, with a negative voltage outputted to a negative terminal. The non-inverted input terminal of an op-amp 23 is connected to the source of the sense FET 6, and the inverted input terminal is connected to a terminal PGND. A second power supply circuit 20 generates a power supply as a negative terminal is connected to a terminal ICGND. A series circuit of FETs 21 and 22 is connected in parallel to the second power supply circuit 20, and the common connection point of the series circuit is connected to the other terminal of the resistor 18, whereby the electricity-conducting state of the FETs 21 and 22 is reciprocally controlled in accordance with a change in the level of an output signal of the op-amp 23. An A/D converter 19 detects a current flowing in the resistor 18 on the basis of the voltage of the common connection point.SELECTED DRAWING: Figure 1 |
