Abstract: A power converter comprises an inductor (L) and a main switch (M1) having a main current path, the inductor (L) and the main current path are arranged in series to receive a DC-input voltage (VIN). A control circuit (CC) controls on-periods (Ton) and/or off-periods (Toff) of the main switch (M1) to stabilize an output voltage (VO) supplied to a load (LO). The control circuit (CC) further has an input (IN) to receive a measuring signal (MS) to protect the main switch (M1) against situations of overvoltage. A measuring circuit (MC) is coupled to a junction (J1) of the inductor (L) and the main current path to obtain the measuring signal (MS) which is indicative of a voltage across the main current path. Preferably, the measuring circuit (MC) comprises a peak-clamp.

Abstract: A DC-DC converter includes a switch (S1) which periodically connects an inductor (L) to a DC-input voltage (Vi) during an on-period (Ton) of a period time (Tp). The operating frequency (fo) of the DC-DC converter is the inverse of the period time (Tp). An output (O1) of the DC-DC converter is coupled to the inductor (L) to supply an output voltage (Vo). A controller (CO) controls the operating frequency (fo) of the DC-DC converter to be substantially proportional to the output voltage (Vo) to obtain a substantially constant average duration of the on-period (Ton) as function of the output voltage (Vo).

Abstract: The invention concerns switched mode power supplies, and a current mode control circuit for such a power supply. In one of the described embodiments of the present invention, instead of employing a sense resistor directly in the primary circuit, line voltage and primary current are emulated by means of an auxiliary winding (130) on the primary side. Current flowing in a resistor (R1) is buffered by means of first and second current mirrors (312, 313) to provide a voltage varying over time at an input of a pulse width modulator (322). This voltage is utilized to provide current mode controlled operation of the switch mode power supply.

Abstract: The present invention relates to a switched-mode power supply comprising a transformer (T1) having an additional control winding (N2). This control winding (N2) forms part of an over power protection system by providing information relating to the line voltage Vline. Additionally, the control winding (N2) forms part of an over voltage protection system by monitoring the output voltage, Vout, of the switched-mode power supply. The sensing of Vline and the monitoring of Vout is performed in a time phased way so that the same control winding (N2) may be used to provide a plurality of information relating to the performance/status of the switched-mode power supply.

Abstract: The present invention relates to a switched-mode power supply comprising a transformer (T1) having an additional control winding (N2). This control winding (N2) forms part of an over power protection system by providing information relating to the line voltage Vline. Additionally, the control winding (N2) forms part of an over voltage protection system by monitoring the output voltage, Vout, of the switched-mode power supply. The sensing of Vline and the monitoring of Vout is performed in a time phased way so that the same control winding (N2) may be used to provide a plurality of information relating to the performance/status of the switched-mode power supply.

Abstract: A converter for the conversion of an input voltage between a first supply terminal and a second supply terminal into an output voltage, including a switching means which in operation are turned on and off alternatively under control of a control signal, an inductive element which together with the switching means forms a series arrangement coupled between the firs supply terminal and the second supply terminal, a control circuit for supplying the control signal, and evaluation means for evaluating a voltage across the switching means, which voltage exhibits ringing, and for supplying an evaluation signal to the control circuit. The frequency of the control signal is approximately constant and is determined by an oscillator.