Regulator circuit, corresponding system and method

A power supply system, comprising:

• a high-voltage source;
• low-voltage circuitry;
• and
• a circuit, including:
• a first electronic switch coupled between the high-voltage source and the low-voltage circuitry;
• a second electronic switch coupled between the voltage-sensing node and the first electronic switch;
• a comparator coupled to the voltage-sensing node, the comparator configured to compare a voltage at the voltage-sensing node with a threshold and generate a switch-on signal in response to the voltage reaching said the threshold;
• and
• a charge pump coupled to the first electronic switch and the second electronic switch.

A method, comprising:

• coupling low-voltage circuitry to high-voltage source by switching a first electronic switch to a conductive state;
• coupling a second electronic switch between a voltage-sensing node and the first electronic switch;
• coupling the voltage-sensing node to the first electronic switch by switching the second electronic switch to a conductive state in response to a voltage at the voltage-sensing node reaching a threshold;
• moving electric charge from a current flow path of the first electronic switch to a control node of the first electronic switch by activating a charge pump with the second electronic switch after switching the second electronic switch to the conductive state.