| 摘要 |
PROBLEM TO BE SOLVED: To provide an active filter circuit which can supply any desired voltage to a load of the poststage by using an inexpensive power MOSFET having a small power dissipation against heat. SOLUTION: The amplification degree of a voltage error amplifier circuit which is incorporated in an ordinary active filter circuit for constantly maintaining the output voltage is set at 2 to 3. As a result, the surface temperature of a power MOSFET is suppressed to about 88-100 deg.C when the input voltage is 90V to 200V as shown by the solid line (l) of the figure for the amplification degree of 2 or alternate long and short dash line (2) for amplification degree of 3 and a desired output voltage of 250-370V can be obtained. |
