Multiple output switching power supply having one controlled output voltage and load compensation

Claim 1

1) Multiple output switching power supply providing a first directly controlled output voltage between a first output and ground and indirect control of at least a second output voltage between a second output and ground, comprising a transformer having at least a primary winding and at least two secondary windings, periodical voltage pulses being induced in said secondary windings, said voltage pulses loading, through rectifying elements, a first capacitive element, having a grounded terminal, at a first voltage V1 and a second capacitive element, having a grounded terminal, at a second voltage V2, equal in sign to V1 but having a lower value, said voltages being available, for loads powering, respectively at said first output and at said second output, characterized in that said first capacitive element comprises a first and a second capacitor, series connected between said first output and ground, the node common to said first and second capacitor being connected to said second output through a diode, said first and second capacitors having a value such that said first voltage applies to said node a voltage level equal or slightly higher, in absolute value, than said second voltage, said diode being conductive in the direction which allows power flow from said first capacitive element to said second output terminal and said second capacitive element.