A switched mode power supply operating with current mode regulation comprises an output switch coupled to a first winding of a transformer and to a source of input supply voltage. The switch is responsive to a control signal for initiating a pulse width modulated pulse voltage in a second winding of the transformer. A supply circuit coupled to the second winding generates an operating voltage. A feedback signal source monitors both current flowing through the first winding and the operating voltage. A control circuit coupled to the feedback signal source includes an oscillator for generating the control signal at a substantially constant frequency during normal operation and at a variable frequency during abnormal operation. The control circuit is responsive both to the current and to variations of the operating voltage over a regulating range, in a negative feedback loop. The control signal varies the on-time conduction of the output switch in each cycle to stabilize the operating voltage. The oscillator has a frequency control responsive to variations of the operating voltage outside of the regulating range, in a positive feedback loop. The on-time conduction of the output switch is limited to a maximum value by comparing the current to an error signal related to the operating voltage. The error signal varies when the operating voltage is within the regulating range but is limited in magnitude when the operating voltage falls below the regulating range. A DC feedback voltage forms a part of both the negative and positive feedback loops.

Switched power supply with current mode regulation

A resonant inverter is operated in a manner to provide a substantially constant output voltage to a load. The inverter is controlled using either a frequency control mode or a phase shift control mode. In the frequency control mode, a constant output voltage is maintained through frequency variation of the rectangular wave signal applied to the resonant circuit of the inverter. In the phase shift control mode, constant output voltage is maintained by phase shifting one component signal of the rectangular wave signal relative to another component signal thereof while maintaining constant the frequency of both component signals. Mode switching occurs automatically at the extremities of the operating frequency range of controllable switch means in the resonant inverter.

Resonant inverter with improved control

An improved DC to DC converter that is capable of operating in both a continuous mode for providing one or more higher levels of output current, and an intermittent mode in order to provide improved efficiency at one or more extremely low output current levels The DC to DC converter (16) includes a power input for receiving power at a predetermined input voltage The converter (16) is current-controlled to provide output power at a predetermined output voltage and several output current levels The converter is further selectively controlled for either continuous or intermittent mode of operation The continuous mode provides the higher output current levels and the intermittent mode provides the lowest output current level

DC to DC converter

A flyback feedforward circuit for a pulse width modulated DC power supply in which the duty cycle is determined by varying the slope and peak amplitude of the sawtooth waveform under the influence of a weighted sum of input and output voltages.

Flyback feedforward pulse width modulation regulator

A contactless power transmitting system includes a power transmitting circuit and a power receiving circuit that are coupled by a transformer having a primary coil and a secondary coil. The power transmitting circuit includes a switching power supply having a predetermined frequency. The power receiving circuit includes a capacitor that is connected to the secondary coil and that constitutes a resonating circuit in cooperation with the leakage inductance of the secondary coil and a flyback rectifier circuit. The capacitance of the capacitor is set so that the resonant frequency of the resonating circuit is substantially equal to the predetermined frequency of the switching power supply.

Contactless power transmitting system and contactless charging system

A tuned switched-mode power supply for producing a stabilized d.c. output voltage by controlling the duration of the conducting period of a bidirectional switch as a function of the output voltage. The drive switching pulses for the switch are subjected to a pulse duration modulation control followed by a frequency control in such a way that the switch-off pulses have a substantially pre-determined time duration which is longer than half a cycle of the tuning frequency of the power supply.

Tuned switched-mode power supply

Line deflection circuit in which the deflection coil is east-west modulated. In order to cancel an east-west dependent horizontal linearity defect the inductance value of the linearity correction coil is made independent of the field frequency, for example by means of a compensating current. In an embodiment this current is supplied by the shunt coil of the east-west modulator.

Circuit arrangement in an image display apparatus for (horizontal) line deflection

A line deflection current generator and a diode modulator for influencing the amplitude of the generated deflection current but without influencing the d.c. voltages which are also generated by the generator, a controllable switching device, for example, the series arrangement of a coil and a thyristor being included in parallel with one of the diodes of the diode modulator and with the opposite direction of conduction. This controllable switching device can also serve as control element for the amplitude modulation.

Circuit for generating a sawtooth line deflection current

Circuit arrangement for producing a sawtooth current in a coil

A circuit for generating both line deflection current and final anode voltage that has main and auxiliary generators. The main generator supplies part of the deflection current and the anode voltage, while the auxiliary generator supplies the remaining part of the deflection current. The main generator is stabilized against anode voltage variations as a result of the beam current variations and component ageing, its operating line being located just above or at the limit of saturation. The auxiliary generator is stabilized against supply voltage variations and its stabilizing circuit can also be modulated by a parabola voltage of field frequency in order to correct the East-West pincushion distortion.

Antonius Boekhorst

Papers

Tuned switched-mode power supply

Circuit arrangement in an image display apparatus for (horizontal) line deflection

Circuit for generating a sawtooth line deflection current

Circuit arrangement for producing a sawtooth current in a coil

Circuit arrangement for generating a sawtooth current in a line deflection coil for a display tube conveying a beam current and for generating an eht