| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent a constant-current drooping value from being significantly affected by an output voltage value when selecting and switching one of output powers in an insulation type DC power source device provided with an output power switching function.SOLUTION: A primary-side control circuit comprises: a constant voltage control circuit configured to ON/OFF control a switching element based on an oscillation signal from an oscillation circuit and output from a comparator such that a secondary-side output voltage is constant; a constant current control circuit configured such that a secondary-side on-duty is calculated according to a drive pulse of the switching element and when the secondary-side output current is equal to or greater than a predetermined value, a signal for controlling the switching element is generated based on the on-duty such that output current is constant; and switching means configured such that a voltage in which the current of primary-side winding is changed and the gain of a path along which the dielectric voltage of auxiliary winding is transmitted are changed according to an output voltage value specifying signal supplied from outside, and the clamp value of a limiter circuit and the upper limit value of the on-duty are switched.</p> |
