A circuit includes a current controlled oscillator (CCO), and a charge pump circuit boosting a supply voltage to produce a charge pump output voltage at a charge pump output node in response to output from the CCO. A current sensing circuit includes a first resistor coupled between the charge pump output node and an output node, a first transistor having a first conduction terminal coupled to the charge pump output node through a second resistor, and a second conduction terminal coupled to an input of the CCO. A second transistor has a first conduction terminal coupled to the output node, a second conduction terminal coupled to a reference current source, and a control terminal coupled to the control terminal of the first transistor and to the second conduction terminal of the second transistor.