摘要 |
There is disclosed a voltage supply stage comprising an input supply voltage, a first (102) and second (104) switch connected in series, the first (102) and second (104) series-connected switches being connected in parallel with the input supply voltage between first and second terminals of the input supply voltage, a third (106) switch and capacitor connected in series, the series-connected third (106) switch and capacitor being connected in parallel with the first (102) switch, a fourth (108) switch connected between the connection of the third switch and the capacitor and an output, and a fifth (110) switch connected between the output and a terminal of the input supply voltage, wherein: in a first phase of operation, the first and the fourth switch are closed, and the second, third and fifth switches are open; in a second phase of operation, the second, third and fifth switches are closed, and the first and fourth switches are open; and the duty cycle of the first and second phases is controlled such that the average voltage on the output varies between 0 volts and twice the input supply voltage. |