| 摘要 |
PROBLEM TO BE SOLVED: To sense accurately overcurrents in the inside of a control IC, without using any current sensing resistor. SOLUTION: Each inverter output element comprises a power transistor having a sensing terminal. A sensed current IS of each inverter output element is converted into a sensed voltage VS by a resistor RS provided in the inside of an IC. A comparator 3 outputs a gate-off signal to a gate driver 9 based on the result of comparing the sensed voltage VS with a reference voltage VO. Also, in order to preventing any erroneous sensing caused by environmental conditions, the respective resistors RO, RS provided in the inside of the IC are disposed in the same place and the same orientation and formed by the same process to set to the respective resistors RO, RS the substantially same characteristic (inclusive of temperature characteristic). Further, such a characteristic as to cancel the variations of the sensed currents of the inverter output elements is given to a power supply VR. |
