| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply unit for CRTs, wherein reducing the ripple of its output voltage, the linearity of its vertical deflection voltage is maintained so as to eliminate the upper and lower displaying shrinkages of its displaying picture plane. SOLUTION: In this unit, there are provided with a converter transformer 11 for supplying positive and negative polarity output voltages V+, V- with the same absolute value, a difference detecting means 14 for the difference voltage between the positive and negative polarity output voltages V+, V- by using the negative polarity output voltage V- as the reference, and a voltage-comparing means 15 for comparing the foregoing difference voltage with a predetermined voltage In this case, transferring a comparison signal 151a formed by the voltage comparing means 15 to the primary side of the converter transformer 11 by using an insulation transferring means 16, an on/off duty signal formed using a converter controlling means 17 is applied to a switching means 18 so as to control the transferring of energy to the secondary side of the transformer 11, by switching on or off charging and discharging of an electric energy to the converter transformer 11. |
