Abstract: Consistent with an example embodiment there is a method of controlling a resonant power converter; the power converter includes first and second series connected switches connected between a supply voltage line and a ground line and a resonance circuit, having a capacitor and an inductor. The resonance circuit is connected to a node connecting the first and second switches. The method comprises repeated sequential steps of closing the first switch to start a conduction interval; sampling a voltage across the capacitor to obtain a sampled voltage level; and opening the first switch to end the conduction interval when a voltage across the capacitor crosses a voltage level determined by addition of the sampled voltage level with a predetermined voltage difference; wherein controlling the predetermined voltage difference determines a power output of the resonant power converter.

Abstract: A controller for an SMPS is disclosed. The controller applies a frequency jitter to the SMPS to reduce Electromagnetic Interference (EMI) and/or audible noise. A second input variable is multiplied by a correlated jitter signal, in order to compensate the output power for the frequency jitter. A corresponding method is also disclosed. Since the jitter compensation occurs within the controller, the method is particularly suitable for controllers operating under different control modes for different output powers (or other output criteria). The multiplicative compensation is applicable across a wide range of converter types.

Abstract: A controller for a switched mode power supply, the switched mode power supply comprising one or more windings. The controller comprising a fixed speed timer; a threshold setter configured to set a threshold for the timer in accordance with a peak value of a current through one of the one or more windings; a secondary stroke detector configured to start the fixed speed timer upon detection of the start of a secondary stroke of the switched mode power supply; a sampler configured to sample a voltage across one of the one or more windings when a count of the fixed speed timer reaches the threshold.

Abstract: A switching circuit (400) comprising an inductive component (406) including at least one winding; and a switch (404) is configured to transfer power from a voltage source (402) to the inductive component (406) in accordance with a switch control signal (412). The switching circuit (400) also comprises a controller (408) configured to integrate the voltage across the inductive component (406) in order to generate a signal representative of magnetic flux in the inductive component (406); and use the signal representative of the magnetic flux in the inductive component to account for a peak magnetization current value in order to control the switch (404).

Abstract: A method is disclosed of controlling a switched mode converter comprising a switch and for providing power to device having a load, comprising: in response to the load exceeding a first threshold, operating in a first mode, being a CCM; in response to the load exceeding a second threshold and not exceeding the first threshold, operating in second mode, being a BCM without valley skipping wherein the switching frequency increases with decreasing load; in response to the load exceeding a third threshold and not exceeding the second threshold, operating in a third mode, being a BCM with valley skipping, wherein the switching frequency depends on the load and the number of valleys skipped and is between a fixed upper and a lower switching frequency limit; and in response to the load not exceeding the third threshold, operating in a fourth mode, being a BCM with valley skipping, wherein the switching frequency depends on at least the load, and is between an upper and a lower switching frequency limit wherein the u

Abstract: A switched mode power supply (SMPS) is disclosed. The SMPS includes a mechanism for discharging charge stored in an input capacitor, upon the SMPS becoming disconnection from the mains, for instance by being unplugged. The SMPS includes a detector for detecting the disconnection of the mains, and a discharge circuit. The discharge circuit comprises a discharge element. The discharge element may be a part of the SMPS which is used otherwise, for instance, a high-voltage current source, or a bus capacitor or it may be an additional element, for instance a resistance load. The discharge circuit is adapted for, in response to the detector detecting a disconnection of the mains, discharging the input capacitor along a path. The detector controls a switch which engages the discharge circuit upon the detection. The switch forms a part of the discharge path.

Abstract: A circuit (1202) for a resonant converter (1204; 1326), the resonant converter configured to operate in a burst mode of operation, the circuit configured to: receive a signal (1206; 1308) representative of the output of the resonant converter; compare the received signal (1206; 1308) representative of the output of the resonant converter with a reference signal (1208; 1304) in order to provide an error signal (1310); and process the error signal (1310) in order to provide a control signal (1210; 1328), wherein the control signal (1210; 1328) is configured to set the switching frequency of the resonant converter in order to control the output power during the on-time of a burst of the resonant converter.

Abstract: The present invention relates to a noise sensor for an alternating or direct current power supply. The sensor comprises a noise sensing unit and a noise separator. The noise separator is configured to receive first, second and third input signals and provide a first output signal representative of the common mode noise and a second output signal representative of the differential mode noise. The noise sensing unit comprises a first capacitive element, a second capacitive element, a first resistive element and a second resistive element.

Abstract: The invention relates to methods of controlling operation of a resonant power converter and to controllers configured to operate according to such methods. Embodiments disclosed include a method of controlling a power output of a resonant power converter comprising first and second switches (S1, S2) connected in series between a pair of supply voltage lines, a resonant circuit connected to a node between the first and second switches and to an output connectable to an output electrical load, the resonant circuit comprising an inductor and a capacitor, the method comprising: closing the first switch (S1) to start a first conduction interval; setting a first voltage level (902); setting a first time period; and opening the first switch (S1) to end the first conduction interval when a voltage (901) across the capacitor crosses the first voltage level (902) and when a time period from closing the first switch exceeds the first time period (904).

Abstract: A power conversion controller for controlling the operation of a switch in a power conversion circuit, wherein the power conversion controller is configured to operate the switch according to: a variable frequency mode of operation for switching frequencies greater than a minimum threshold value; and a fixed frequency mode of operation at a switching frequency equal to the minimum threshold value.

Abstract: Consistent with an example embodiment, there is a controller for a resonant converter, wherein the controller is configured to operate the resonant converter in a high power mode of operation by adjusting a first control parameter to vary the output power and a low power mode of operation by adjusting a second control parameter to vary the output power. The controller is configured to set the value of the first control parameter when changing over between the high power mode of operation and the low power mode of operation such that the output power is substantially consistent during the changing over.

Abstract: An example embodiment relates to a switched-mode power supply comprising a transformer with a first winding and a second winding. There is a transmitter configured to: detect a detectable variable (Vout) at the first winding, generate a transformer relayed signal in accordance with the detectable variable (Vout), and provide the transformer relayed signal to the first winding. A receiver is configured to: receive the transformer relayed signal from the second winding, and control a controllable variable at the second winding in response to the transformer relayed signal, wherein the transformer relayed signal is a symbol stream comprising a plurality of symbols.

Abstract: A noise filter circuit uses open loop signal processing to process the signal that causes the noise and generate a signal to be fed back into the system to cancel noise currents.

Abstract: An electrical power converter has a transformer (4) and detecting circuitry for deriving a reconstructed output or load current. In a first aspect of the invention the load current is computed by subtracting a scaled version of the time integral of the primary voltage (Vcap) from a scaled version of the primary current (Iprim). In a second aspect of the invention the load current is computed by subtracting a scaled version of the time integral of the voltage (Vaux) across an auxiliary winding (24) from a scaled version of the primary current (Iprim).

Abstract: A control circuit for a switched-mode power supply having an input side (101) connectable to an electrical power source and an output side (102) connectable to a load.

Abstract: Consistent with an example embodiment, there is a method of controlling a synchronous rectifier having an input signal having oscillations therein and a switch which is switchable between an open state and a closed state. The method comprises filtering the input signal to produce a filtered signal, comparing the filtered signal with a reference value, and opening the switch in response to the comparison, in which the filtering is active filtering. The active filtering may be based on determination of the peaks (positive and/or negative) of the signal, either directly, including a quarter period offset, or including decay—or a combination of the above; alternatively, the active filtering may be based on the a smoothing functions such as a switched low-pass filter or a short time integrator.

Abstract: Consistent with an example embodiment, there is a control method which reduces the steps: instead of a constant on-time for the switch, the duration of the on-time is increased each time an additional valley to be skipped. The predetermined increase may be either a fixed fractional increase or a further additional increment; it may be determined by a small regulation loop that multiplies the on-time from the main loop with a factor equal to the ratio between measured period time and the sum of primary and secondary stroke times.

Abstract: A controller for an SMPS is disclosed. The controller applies a frequency jitter to the SMPS to reduce Electromagnetic Interference (EMI) and/or audible noise. A second input variable is multiplied by a correlated jitter signal, in order to compensate the output power for the frequency jitter. A corresponding method is also disclosed. Since the jitter compensation occurs within the controller, the method is particularly suitable for controllers operating under different control modes for different output powers (or other output criteria). The multiplicative compensation is applicable across a wide range of converter types.

Abstract: A method of operating a resonant power supply in standby mode is disclosed, in which the switching period of the power supply is longer than the resonance period. The power converter is operated in normal mode for a significant fraction of one resonance period. Efficient operation is maintained, despite the switching period being extended beyond the resonance period, by using resonance current to enable soft switching, where this is beneficial, and dumping the resonance current into the load where this is more beneficial. Control methodologies to regulate the output power are also disclosed.

Abstract: An electrical circuit for emulating a capacitance, comprises a physical capacitor which is charged by charge flow from the input of the electrical circuit. An amplifier amplifies the voltage at the input of the electrical circuit such that the physical capacitor is charged with a larger change in voltage than the change in voltage at the input. This implements an effective multiplication of capacitance. A reset system resets the physical capacitor without drawing charge from the input of the electrical circuit. This extends the voltages which can be provided to the input.