Abstract: This invention generally relates to discontinuous conduction mode switch mode power supply (SMPS) controllers employing primary side sensing. We describe an SMPS controller which integrates a feedback signal from a point determined by a target operating voltage to a peak or trough of an oscillatory or resonant portion of the feedback signal when substantially no energy is being transferred to the SMPS output. When regulation is achieved this value should be zero; the difference from zero can be used to regulate the output voltage of the SMPS.

Abstract: This invention relates to switch mode power supply (SMPS) controllers employing primary side sensing. We describe an (SMPS) controller which uses an area correlator to compare an area under a feedback signal waveform between a start point defined by said first timing signal and an end point defined by said second timing signal with a reference area. An output of the area correlator provides an error signal for regulating the SMPS output.

Abstract: This invention relates to SMPS controllers employing primary side sensing to detect a point of zero magnetic flux, at which the output voltage of the SMPS may be sampled accurately on the primary side. We describe a switch mode power supply (SMPS) controller for regulating the output voltage of an SMPS is response to a feedback signal from an auxilliary winding of a magnetic energy storage device forming part of an output circuit of the SMPS, the SMPS controller comprising: a reference level input to receive an output reference level signal; an input to receive said feedback signal, said feedback signal being responsive to a voltage on said auxilliary winding of said magnetic energy storage device; an integrator to integrate a difference between said feedback signal and a first fixed reference level signal; a first comparator to compare an output of said integrator with a second fixed reference level signal and to provide an output responsive to said comparison for regulating said SMPS output voltage.

Abstract: This invention generally relates to saturation detection circuits, in embodiments for substantially lossless detection of saturation of power switches in power integrated circuits. We describe a saturation detection circuit for detecting saturation of a power semiconductor device, the circuit including a said power semiconductor device having an input terminal and an output terminal, a second semiconductor device connected across said input and output terminals of said power semiconductor device, and a circuit responsive to a current flowing through said second semiconductor device to detect said saturation of said power semiconductor device.

Abstract: This invention generally relates to discontinuous conduction mode switch mode power supply (SMPS) controllers employing primary side sensing. We describe an SMPS controller which integrates a feedback signal from a point determined by a target operating voltage to a peak or trough of an oscillatory or resonant portion of the feedback signal when substantially no energy is being transferred to the SMPS output. When regulation is achieved this value should be zero; the difference from zero can be used to regulate the output voltage of the SMPS.

Abstract: This invention relates to Switch Mode Power Supply (SMPS) controllers, especially analogue controllers employing a combination of Pulse Width Modulation (PWM) and Pulse Frequency Modulation (PFM). We describe a switch mode power supply (SMPS) controller circuit for controlling a power switching device of said SMPS, the circuit including: a current input to receive a feedback signal current dependent upon an output voltage of said SMPS; a ramp generator circuit coupled to said current control input to generate responsive to said feedback current signal consecutive first and second voltage ramps, one rising the other falling; and a control output responsive to said voltage ramps from said voltage ramp generator to provide a drive signal for controlling said power switching device.