摘要 |
The invention relates to a voltage converting circuit ( 2 ) having:-an input terminal ( 11 ) for connection 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 gate electrode ( 31 ) for opening and closing of the switch when a control voltage of a first level is applied to the gate,-an oscillator ( 13 ) comprising a power input ( 14 ) connected to the output terminal ( 12 ), a start-up output ( 15 ) connected to the gate electrode ( 31 ) of the first switch ( 6 ) for supplying a pulse-like signal to the 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 gate electrode ( 32 ) connected to the oscillator output ( 16 ), wherein the first switch ( 6 ) remains 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.
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