Flextronics Ap, LLC

Friwo Mobile Power Gmbh

Power Systems Technologies Gmbh

Rüdiger Malsch

Ralf Schröder Gen Berghegger

Armin Wegener

Ralf Gennant Berghegger Schroder

Ralf Schröder

The invention under consideration refers to a controller for a primary-side regulated control power supply unit for the regulation of the output of the primary regulated control power supply unit. The invention also concerns a method for the operation of a control power supply unit of the generic type and a pertinent control power supply unit. The controller comprises a control output (B), which can be connected with the control input of a primary-side switch (Q) of the control power supply unit; a voltage measurement input (U), which can be connected with a primary-side auxiliary winding (L) of a transformer () for the sensing of an auxiliary voltage, which is induced as a function of the secondary-side output voltage; a sample-and-hold element (SuH, SuH) for the sensing of the auxiliary voltage; and an error amplifier () for a comparison of the sensed auxiliary voltage with a reference value (Vref) and for the amplification of the deviation between the sensed auxiliary voltage and the reference value. The controller (IC) also has a return branch for the return of the output signal of the error amplifier () to the voltage measurement input (U).

Control circuit for a primary controlled switched mode power supply with improved accuracy of the voltage control and primary controlled switched mode power supply

The present invention relates to a control circuit for controlling the output power of a primary-controlled switched mode power supply unit, which comprises a primary switch and a transformer with an auxiliary winding. Within the auxiliary winding, voltage pulses are induced by primary-sided switching operations, which can be taken into account when controlling the output power. In order to provide an improved control and an enhanced flexibility with respect to the operational parameters, the sampling instance is determined based on the duration of the voltage pulse at the auxiliary winding during a previous switching cycle. In order to detect a defective contact between the auxiliary winding and the control circuit in a particularly simple and secure manner, the negative voltage pulse at the auxiliary winding occurring when the switch is closed may be used for confirming a proper connection. In order to optimize the switching off process of the switch and to reduce power losses, the output power may be controlled by comparing the current through the primary winding with two threshold values.

Control circuit for switched mode power supply unit

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Bad Schandau, Germany

Rüdiger Malsch