| 摘要 |
PURPOSE:To protect the circuit in a shortcircuit mode by obtaining the time until a main transistor starts conducting after the transistor is interrupted for a period longer than the prescribed time. CONSTITUTION:The instruction signal corresponding to the base signal of a transistor QU repeates ON and OFF in the instructin signal, and the instruction signal corresponding to the base signal of the main transistor QX maintains OFF state in the meantime. Consequently, the load current IU of U phase flows toward a load. At this time, the main transistor QU repeates ON and OFF for controlling the current, and the load current IU at this time alters in the route as below. That is, when the main transistor QU is ON, the load current IU flows through the main transistor QU. When the base current IBQU of the transistor QU becomes zero next, collector current will flow due to the storage time of the main transistor QU. When the main transistor QU becomes interrupted, the load current IU is immediately transferred to the diode DX. |
