| 摘要 |
PURPOSE:To prevent a switching element from being destroyed by a method wherein any one of the switching elements on the primary side is turned off in proportion to an increase in output current or a reduction in output voltage in a multiplex switching regulator. CONSTITUTION:Switching elements 2, 3 in a square-law type switching regulators are used to chop an input voltage 1 with a phase difference by 180 deg. so that square waves with differentiated phases by 180 deg. are generated on the secondary side of transformers 8, 9. The square waves are converted into DC current by a rectifier smoothing circuit consisting of diodes 10, 11, a reactor 13 and a capacitor 14 to supply DC voltage to a load 15. A pulse width controller 16 controls 'on' time during which switching elements 2, 3 are turned on so that the output voltage Vo can be maintained constant. The controller works to turn off the switching element 3 when the output current exceeds the specified limit, or when the output voltage becomes lower than the specified limit, to permit the element 2 only operates. |
