Patent ID: 6141232
Filing Date: 2000-10-31
Classification: H02M

Abstract:
A flyback converter provided with a transformer, having a primary winding and having a secondary winding, the primary winding being connected in series with a controlled switch to an input direct voltage and the secondary winding being connected in series to a rectifier and a charging capacitor connected downstream of the secondary winding, comprising:an actuation circuit for supplying start pulses of a fixed frequency for the controlled switch, said actuation circuit including a current sensor for current flowing through the primary winding, a first rectifying amplifier for comparing the output voltage with an adjustable voltage reference value,a second rectifying amplifier for comparing the output current with an adjustable current reference value as a control signal derived from the output signals of the two rectifying amplifiers and the output signal of the current sensor of the actuation circuit is supplied for the purpose of influencing the pulse duty ratio, and the maximum output of the converter-primary part is lower than the product of the output voltage which can be adjusted to a maximum degree and the output current which can be adjusted to a maximum degree; whereinthe reference values which can be adjusted to a maximum degree correspond to the voltage and current values with which the secondary part can be loaded to a maximum, andthe level of the control signal is limited by a limiter, wherein the point at which the limiter is used is selected in such a way that a maximum breaking current in the primary circuit is established corresponding to the maximum permissible power loading of the primary circuit.