Patent ID: 7081739

Claim:
Voltage converting circuit ( 2 ) having: an input terminal ( 4 ) for connecting to a varying voltage or current source, and an output terminal ( 12 ) with a supply voltage, an inductive element ( 5 ) being with a first terminal connected to the input terminal and with a second terminal to a capacitive element ( 8 ) and to the output terminal ( 12 ), the capacitive element ( 8 ) being with one terminal connected to a reference voltage ( 9 ), a first switch ( 6 ) being with a first terminal connected to the second terminal of the inductive element ( 5 ), and with a second terminal to the reference voltage ( 9 ), the first switch ( 6 ) comprising a first gate electrode ( 31 ) for opening and closing of the first switch when a control voltage of a first level is applied to the first gate electrode ( 31 ); a first oscillator ( 13 ) comprising a power input ( 14 ) connected to the output terminal ( 12 ), a start-up output ( 15 ) connected to the first gate electrode ( 31 ) of the first switch ( 6 ) for supplying a pulse-like signal to the first gate electrode ( 31 ) and an oscillator output ( 16 ), and a second switch ( 7 ) connected in parallel with the first switch ( 6 ), the second switch having a second gate electrode ( 32 ) connected to the oscillator output ( 16 ), the first switch ( 6 ) remaining opened when the supply voltage at the output terminal ( 12 ) reaches a predetermined level, and the second switch ( 7 ) is operated by the oscillator output ( 16 ) at a second voltage level that is higher than the first voltage level, characterized in that the first oscillator ( 13 ) comprises low voltage inverter ports able to generate output voltages for said start-up output ( 15 ) when said power input ( 14 ) receives an input voltage of below 0.4 V and that a clamp diode (D 4 ) is connected between the second terminal of the inductive element ( 5 ) and the first gate electrode ( 31 ).