A method for limiting the output current of a switched-mode power supply of flyback type in overload situations,and a switched-mode power supply of flyback ty

摘要

The invention relates to a method for limiting the output current (Iout) of a switched-mode power supply of flyback type in overload situations and to a switched-mode power supply of flyback type. In accordance with the method, the output current (Iout) is limited by means of pulse width modulation (PWM) by adjusting, by means of a control circuit (13) known per se, the ratio of the duration of the ON and OFF phases of the switch (SW) of the primary circuit. In order for the output current not to increase inordinately in overload situations, the voltage (Vs) which is present on the primary side of the transformer (10) and which is dependant on the output voltage (Uout) of the power supply is utilized to control a current generator (21), and output current (Icc) of which is used to form a control signal for the control circuit (13). IMAGE