| 摘要 |
PURPOSE:To attain the drive of the load by eliminating the change of the switching speed due to the change of the gate capacity of a power MOSFET and regenerating accurately the duty of the pulse signal received from a load controller. CONSTITUTION:A time constant circuit 12 decides the rising and falling times of a pulse signal consisting of the output of a microcomputer of a load controller 25, etc. A comparator 13 applies the conduction/cut-off control to the transistors TR1 and TR2 of a drive circuit 14 so as to secure the coincidence between the output of the circuit 12 and the gate voltage of the MOSFET 15. As a result, the gate current varies to the change of a gate capacity 30 and therefore the switching speed of the MOSFET 15 never changes. Thus a load 16 can be accurately driven in accordance with the duty of the pulse signal. Furthermore the switching timing can be optionally set with the change of the current capacity of both current sources 22 and 23. |
