there is described a voltage booster circuit for powering a piezoelectric actuator of an injector , and having a first and a second input terminal supplied with an input voltage ; a first and a second output terminal supplying an output voltage greater than the input voltage , the second input terminal and second output terminal being connected to each other over a common line ; a first and a second inductor coupled magnetically and connected in series between the first input terminal and the first output terminal ; a capacitor connected between the first output terminal and the second output terminal ; and a controlled switch connected between the intermediate node between the first and second inductor , and the second input terminal and second output terminal , and which switches between a closed operating state , to permit charging of the first inductor by the input voltage , and an open operating state , to permit transfer of the charge stored in the first inductor to the capacitor via the second inductor .