| 摘要 |
PURPOSE:To reduce the size and cost of an apparatus significantly by a method wherein a circuit construction is simplified and a low frequency transformer is eliminated. CONSTITUTION:A DC power supply 3 and a switching circuit 4 which switches the input from the DC power supply 3 are connected to the primary winding 2x of a power supply transformer 2. Further, an input circuit 5 which supplies an input signal Sp which is obtained by superposing a DC signal Sd on an AC signal Sa and a modulating circuit 6 which applies pulse width modulation to the input signal Sp or a processed signal Se which is obtained by processing the input signal Sp and which performs the switching control of the switching circuit 4 with modulated signal Sm are provided. An output circuit 7 which supplies a superposed voltage Ep and is composed of a rectifier 7d and a low- pass filter 7c is connected to the secondary winding 2y of the power supply transformer 2. |
