| 摘要 |
Driver (1) for driving a load (L), the driver having BiFRED topology and comprising: - a first input terminal (5) and a second input terminal (6); a pair of output terminals (9a, 9b) for connecting the load; - a Bi FRED converter coupled to the input terminals, comprising: - a first inductor (L1), coupled to a first input terminal (5); - a first capacitor (C1) in series connection with the first inductor; - a controllable switch (S1) between the interconnection of the first inductor and the first capacitor and the second input terminal (6); - a second inductor (L2) coupled between the first capacitor and the second input terminal; - a control device (20; 30) for controlling the controllable switch (S1); wherein said control device (20; 30) comprises: - a first sensing element (21) for sensing the current through said switch (S1) and providing a first output signal proportional to said current, said current being the sum of the charging current of the first inductor (L1) and discharging current of the first capacitor (C1); - a reference device (24) for providing a reference signal; - comparing element for comparing said first output signal with said reference signal, and for switching said switch to a non-conductive state in each transition of the controllable switch's oscillation when said first output signal is equal to or higher than said reference signal; - an output capacitor (C2) connected between said output terminals (9a, 9b); - a second diode (D2) connected in series with said output capacitor (C2); - a second sensing element (25) for sensing the current through said second diode (D2), and for providing a second output signal for switching said switch to a conductive state when said current through said second diode (D2) reaches zero; wherein said second sensing element (25) comprises a sensing inductor (25) inductively coupled to said second inductor (L2) wherein the sensing inductor (25) having one end connected to the second input terminal (6) and having its opposite end coupled to the control terminal of the controllable switch (S1). |
