Power supply for generating at least two regulated interdependent supply voltages

A power supply circuit for generating at least first and second interdependent supply voltages from an input voltage, comprising:

• first and second input terminals for connection to a source of supply voltage for the circuit,
• at least first and second output terminals for supplying said at least first and second interdependent supply voltages, respectively,
• a voltage converter coupled between said input terminals and said output terminals,
• a first control stage having a first input coupled to receive a first voltage determined by the actual value of the supply voltage at said first output terminal and an output coupled to a control input of the voltage converter to supply the voltage converter with a first control signal to control the actual value of the first supply voltage at the first output terminal to a first nominal value that can vary in a range between a first upper limit voltage and a first lower limit voltage,
• a second control stage having an input coupled to receive a second voltage determined by the actual voltage of the supply voltage at said second output terminal and an output coupled to a further input of the first control stage to supply a second control signal thereto whereby the actual value of the second supply voltage at the second output terminal is controlled to a second respective nominal value variable within a voltage range between a second upper limit voltage and a second lower limit voltage by varying the first nominal voltage value in a range between the first upper limit voltage and the first lower limit voltage in response to the second control signal, wherein the second control stage includes means for comparing the second voltage with the second nominal value of the second supply voltage.