| 摘要 |
<p>First main electrodes of second and third semiconductor elements are connected to the first main electrode of the first semiconductor element, control electrodes of the second and third semiconductor elements are connected to the control electrode of the first semiconductor element, a second main electrode of the second semiconductor element is connected to a first resistor, and a second main electrode of the third semiconductor element is connected to a second resistor. Main-electrode voltages of the first and second semiconductor elements are compared with each other by a first comparator, a control voltage is supplied a control voltage to the control electrodes of the first and second semiconductor elements according to an output of the first comparator by control means. Main-electrode voltages of the first and third semiconductor elements are compared with each other by a second comparator. The transistor widths of the second and third semiconductor elements are each smaller than the transistor width of the first semiconductor element. The first semiconductor element is connected to power supply elements in parallel with one another between a power source and a load, and a weak current is detected when the load and power supply elements are OFF. There is no shunt resistor when detecting an overcurrent or a weak current. Accordingly, a heat loss is minimized and detective sensitivity is improved. <IMAGE></p> |
