Multiple voltage switching power supply having output voltage limiting

摘要

A multi-voltage switching power supply having a first pair of switches connected in series with each other across a pair of incoming power lines. The switches are alternately closed at a fifty percent duty cycle. A plurality of pairs of series-connected switches are also connected between the incoming power lines and operated in a pulse-width modulated mode. Power supply circuits are connected between the junction of the pulse-width modulated switches of each pair and the junction of the fifty percent duty cycle switches. The peak value of the current applied to the power supply circuit, which determines the power supply output voltage, is controlled by adjusting the closure time of the pulse-width modulated switches.