| 摘要 |
PURPOSE:To increase the load capacity by supplying the detection currents of plural coils magnetically connected together to a differential amplifier and applying a pulse to the gate terminal of a switching element in response to the deviation between the output of the differential amplifier and a current command. CONSTITUTION:Two coils of an electromagnet 72 are magnetically connected to each other so that their magnetic fluxes are generated in the same direction. Then a comparator 11 compares the signal of a rectangular wave transmitter 12 with the current of the electromagnet 72 to generate the pulse string signal in response to the result of comparison performed between the current of the electromagnet 72 detected by a differential amplifier 8 and the current command input of a comparator 9. A command is sent to a gate driver 13 and the switching elements 1 and 2 are repetitively turned on and off. When both elements 1 and 2 are turned on, the currents flowing to the electromagnet 72 are increased and then reduced vice versa. Therefore the elements 1 and 2 can work in a normal state and with no breakage even if no synchronization is secured between both elements. Thus the load capacity is increased without increasing the capacity of a switching element. |
