| 摘要 |
The invention concerns a method for monitoring and controlling the output current from an electronic drive system of the type that has a switched power supply (1) of fly-back type. The invention concerns also an electronic drive system and the use of such a drive system. According to the method, a switched power supply (1) of fly-back type is used for the driving of a load, for example a non-linear load of light-emitting diodes, whereby the output current (lout) from the power supply is controlled by means of pulse-width modulation through the ratio between the lengths of the ON and OFF phases of a switch in the primary circuit. The output current of the drive system is controlled and monitored through: - the selection of a switched power supply (1) of single-stage type and with a power factor correlation of PF, - the arrangement of a linear current regulator (15) at the output (UCout) of the switched power supply (1), - the regulation of the current (IL) through the load that is connected to the output (Uout) of the linear current regulator (15) by means of the linear current regulator (15), - the measurement and use of the fall in voltage (M1-M2) across the linear current regulator (15) in the formation of a first control signal (S1) that is led through a feedback loop (18, 19; 18, 19, 20) to a primary side of the power supply (1), - the use of the control signal (S1 ) for the control of the output voltage (Uout) of the power supply (1) through regulation of the duty cycle of the switch (SW), - the conversion of an AC voltage (Uin) to a rectified DC voltage (U1 ) that is fed in its raw, unfiltered or solely half-wave rectified form to the input terminals of the power supply (1). |
