Symmetrical output switch-mode power supply

A voltage regulating device comprising

• a power stage comprising an inductor between a first node and a second node;
• a first switch between the first node and a power supply node for which the potential is non-zero and of constant polarity;
• a first capacitor between a node at a reference potential and a second switch coupled to the first node;
• a second capacitor between a node at the reference potential and a third switch coupled to the second node;
• a fourth switch between the second node and a node at the reference potential;
• a fifth switch between the first node and a node at the reference potential;
• a first output for delivering a first voltage corresponding to the voltage at the terminals of the first capacitor;
• a second output for delivering a second voltage corresponding to the voltage at the terminals of the second capacitor;
• the power stage being arranged to adopt one of the following configurations as a function of the control signals:
• a first configuration in which only the first and the third switches are closed;
• a second configuration in which only the first and the fourth switches are closed;
• a third configuration in which only the second and the fourth switches are closed;
• a fourth configuration in which only the third and the fifth switches are closed;
• and
• a control circuit for synchronizing and controlling the switches in order to apply a given control strategy, the control circuit being coupled to the power stage and being able to produce error signals as a function of the difference between the reference potential and the first and second voltages, and to generate the control signals,
• wherein the control circuit comprises a first subtractor able to calculate a first comparison signal representing the result of the difference between the first voltage and the second voltage;
• said control circuit comprising a second subtractor arranged to calculate a second comparison signal representing the result of the sum of the second voltage and the first voltage.