| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress radiation noise though compact in size.SOLUTION: Step-up converters 14, 15 are juxtaposed, and a control circuit 17 drives transistors Q1, Q2 by drive voltages Vg1, Vg2 in opposite phases. The coils of inductors L1, L2 constituting a filter circuit 16 are wound around one and the same core and coupled in opposite phases. Since magnetic fluxes due to DC currents out of currents I1, I2 flowing in the inductors L1, L2 are offset each other, the magnetic flux density of the core is greatly reduced. The cubic volume of the core or the number of windings of the core can be reduced by employing a magnetic material, such as ferrite, having low saturation flux density and high magnetic permeability. Since a toroidal core of closed magnetic structure can be used, it is possible to reduce magnetic leakage flux and suppress radiation noise.</p> |
