A voltage regulator has a first output is connected to a capacitive element. A current source is coupled between the first output and a first node receiving a power supply voltage. The current source delivers a first DC current in response to assertion of a first binary signal. A comparator asserts a second binary signal when a first voltage on the first output is lower than a set point voltage. A first circuit controls assertion of the first signal for a first fixed time period when the second binary signal is asserted.