Abstract: A power supply comprises: a rectifier; a power preconverter coupled to the rectifier; a switched-mode power supply circuit coupled to the power preconverter; and, a phase control circuit for synchronizing operation of the power preconverter with operation of the switched-mode power supply circuit. An energy storage device may be coupled to the power preconverter and to the switched-mode power supply circuit. A preconverter switch conducts during each time interval that a power switch in the switched-mode power supply circuit conducts in order, for example, to charge the energy storage device. The preconverter switch begins conducting only after each time interval begins and always stops conducting before each time interval ends. In a portion of the time interval after the preconverter switch has stopped conducting, a current can flow directly from the power preconverter to the switched-mode power supply circuit without, for example, charging the energy storage device.

Abstract: A multiscan compatible horizontal deflection driving circuit prevents the flow of an excessive current through a transistor in a horizontal deflecting circuit when the frequency of a horizontal synchronization signal is switched. In the horizontal deflection driving circuit according to the invention, when a frequency of an H sync pulse of an input composite video signal decreases, a driving power source voltage is reduced earlier than a reduction of a frequency of a horizontal driving pulse, thereby preventing an excessive collector current from flowing in the transistor in the horizontal deflecting circuit.

Abstract: A display monitor which comprises a flyback transformer for supplying a high voltage to a display and an opposite-phase pulse inducing transformer. The flyback transformer includes a core, a primary-side low-voltage coil wound on the core, a secondary-side high-voltage coil wound on the core and divided into high-voltage coil pieces, rectifier diodes connected in series with respective output sides of the high-voltage coil pieces of the secondary-side high-voltage coil so as to form a series circuit, and a high-voltage capacitor connected to a cathode of one of the high-voltage rectifier diodes in a final stage of the series circuit.

Abstract: A device for driving a directly heated cathode of a cathode ray tube eliminating a delay due to inductance of a transformer. A transformer that produces the heater-heating signal voltage applied to the cathode includes a secondary coil divided into first and second coils. The voltage induced in the first coil is used for the heater-heating voltage and the signal induced in the second coil is synchronized with the voltage induced in the first coil and used as a bias voltage for turning on and off a switching element in synchronization with the heater-heating voltage. The switching element turns on only when the heater-heating signal voltage is applied to a control terminal of the switching element.

Abstract: A circuit for generating a screen voltage is provided. The circuit employs an operational amplifier and two NPN transistors and receives an analog control signal from a microprocessor. The analog control signal is input to the negative input terminal of the operational amplifier. The output screen voltage is taken at emitter of one NPN transistor. In one preferred embodiment, Vcc is taken at a primary side of a high voltage transformer within the display device and input to the collector of the one NPN transistor.

Abstract: A high-voltage stabilization circuit of a monitor can detect accurately a change of a high voltage of a secondary winding of a high-voltage transformer.

Abstract: A power supply for a raster center controller for a video display appliance which can prevent picture movement phenomena of a cathode ray tube which are caused by unstable power supply to the raster center controller due to the change of the horizontal frequency. The power supply for a raster center controller includes coils, provided in a secondary winding of a flyback transformer, for generating and providing to the raster center controller a pulse voltage having a pulse width corresponding to that of a high voltage developed in the flyback transformer, first and second power supply sections, coupled between the coils and the raster center controller, for providing positive and negative supply voltages to the raster center controller by rectifying and performing charge/discharge operation with respect to the pulse voltage developed in the coils, respectively.

Abstract: A high-voltage stabilizer circuit for a monitor which stabilizes its output voltage by reducing the overshoot of the output voltage occurring when the power is on. According to the circuit, the high voltages induced in two secondary windings of a flyback transformer are superimposed and provided as a reference signal for pulse-width modulation.

Abstract: Protection of EHT and/or scan output stages in multiscan displays is provided without the use of additional components within the power supply other than those required to perform the power supply function itself. Operation is non-dissipative, conserving power. A drive control signal is AC coupled. The switch is on during retrace of the flyback pulse. The drive control signal is varied in accordance with the load, becoming active longer and longer periods of time with increasing load until the control signal vanishes (becomes continuously asserted), turning off the switch. In accordance with a further feature of the invention, feedback to a controlling integrated circuit concerning an overload condition may be achieved without dedicating a line or pin to a separate feedback signal.

Abstract: A flyback transformer (FBT) driving apparatus for video display appliances which can prevent deterioration of the FBT efficiency caused by excessive horizontal frequency input. The FBT driving apparatus employs a PWM-type circuit to evenly maintain the Vcc power supply provided to the primary winding of the FBT irrespective of the excessive horizontal frequency input. The FBT driving apparatus makes use of the horizontal frequency per se in the low frequency band, while dividing the horizontal frequency by a half in the high frequency band to enable operation of the FBT by means of ordinary rectifying diodes even in the input of the high horizontal frequency and to prevent deterioration of the FBT efficiency caused by input of the high horizontal frequency.

Abstract: A power supply for producing a high DC output voltage. The power supply comprises a primary winding and a secondary winding coupled together by a magnetic circuit. The secondary winding comprises a series of independent coils or turns. Each coil includes a rectifier element for converting the induced AC voltage into a DC voltage. The rectifier elements are connected in series to produce a high level DC voltage output signal, for example, a minimum 50 kV output. The secondary coils have a turns ratio such that the induced voltage is less than the Paschen minimum voltage for the gaseous medium surrounding the secondary coils. The power supply may be fabricated using surface mount technology or as a printed circuit board where the secondary coils are formed as tracks on the substrate.

Abstract: A diode-split high voltage transformer for a television receiver includes a coil form having a plurality of axially aligned cells. The cells are arranged in groups and are separated by fins. Partial windings are individually arranged in the cells. A plurality of diodes is arranged about the edge of each fin and and substantially normal to the of the form. The partial windings and the diodes are alternately connected in series. Each of the fins includs a ramp-shaped recess tangentially extending from the fin edge to the bottom of the cell adjacent to the fin to provide space allowing the winding wires to stay clear of the partial windings.

Abstract: A device for adjusting a horizontal raster size in a monitor is disclosed, wherein, by detection of beam current applied to a cathode ray tube of induced voltage across a flyback transformer. An error detector detects overvoltage or overcurrent and generates a pulse to a frame compensator. A variation in size of horizontal raster is regulated by controlling output signal of a horizontal output and deflection circuit, whereby a stabilized video frame in horizontal size is obtained.

Abstract: There is provided a stabilizing circuit for stabilizing the horizontal picuture size on the display of a television receiver, wherein a video signal containing a horizontal synchronizing signal having a horizontal scanning frequency is inputted.

Abstract: A horizontal deflection circuit for a MultiSync.TM. monitor includes a driver transistor, a driver transformer having a primary windings coupled to the driver transistor, a horizontal output transistor coupled to a secondary windings of the driver transformer, a flyback transformer coupled to an output of the horizontal output transistor, and a current source coupled between a voltage source and the primary windings of the driver transformer for stabilizing an output current of the secondary windings of the driver transformer.

Abstract: A horizontal deflection circuit couples flyback pulses from a first transformer winding to a second transformer winding. The second winding is coupled to a source of unregulated DC voltage. A switch has input, output and control terminals. The output terminal is coupled to the first winding. The switch operates with a variable duty cycle for generating a regulated DC voltage at the output terminal. An inductor and a diode are coupled to the second winding. The inductor is also coupled to the input terminal. A pulse width modulator varies the duty cycle of the switch responsive to feedback and timing signals. Drive voltage for the control terminal is supplied by a first capacitor charged during retrace intervals and a second capacitor charged at the end of the retrace intervals by the first capacitor. The second capacitor is coupled to the control terminal and the drive voltage is discharged by the pulse width modulator.

Abstract: A horizontal deflection amplifying apparatus for use in an automatic main power supply such as that for a cathode ray tube is provided. The apparatus uses a microprocessor for the connection of capacitors to a horizontal deflection coil (yoke coil) by controlling the switching operation of relay switches. To prevent the drive transistor of the deflection coil driver from being destroyed or the horizontal deflection coil from being damaged due to excess current, the capacitors are connected or disconnected while the power supply voltage is off (i.e., at a 0V state) and the supply voltage is then re-applied. Thus, the horizontal deflection amplifying apparatus can be safely driven.

Abstract: A focus supply circuit, comprising: a power source for generating a high voltage for energizing a cathode ray tube, including a transformer having a high voltage winding with at least one intermediate output tap; and, a focus screen assembly, having a resistive chain with an input terminal coupled for receiving the high voltage, a focus output terminal for energizing a focus electrode of the cathode ray tube and at least one intermediate input tap between the input terminal and the focus output terminal, coupled to the at least one intermediate tap of the high voltage winding by an independent conduction path. An effective bias current for the cathode ray tube flows in the resistive chain. The voltages at the intermediate taps correspond to one another within a tolerance. The conductive path presents sufficiently low impedance to substantially inhibit variation of the high voltage due to variation of leakage current from the focus electrode.

Abstract: This invention relates to a video display high voltage generator. In the generator, the primary coil, the high voltage coil and the multiple foil high voltage capacitors of the multiplier are sequentially formed into a trausformer assembly on the insulating tube. The stepup capacitors are formed through an electrostatic induction of the metallized foil in the assembly, the two groups of the stepup capacitors are wound on the high voltage coil in opposite directions so as to nullify the voltages magnetically induced thereon, forming the wound metallized foils into pure capacitors without causing electromagnetic interference on the other equipments. The transformer assembly is mounted on the center pole of the ferrite casing and accomodated in the space provided by the casing. The magnetic path is formed by the center pole bases and rim of the ferrite casing.

Abstract: A power generator, including a transformer with a primary winding arrangement and a secondary winding arrangement which is inductively coupled thereto, the primary winding arrangement forming a resonant circuit in conjunction with a capacitor, and a load being connected to the secondary winding arrangement. Therein, one winding arrangement of the transformer forms part of a series resonant circuit and, the other winding arrangement forms part of a parallel resonant circuit, the resonance frequency of the series resonant circuit is lower than the resonance frequency of the parallel resonant circuit, and the primary winding is connected to an alternating voltage generator so that an essentially sinusoidal alternating current flows through the primary winding.

Abstract: In order to cause scan and/or fly-back voltages (Vsca, Vfly) supplied by a horizontal output stage (1) to vary at a desired rate during a change of state in a horizontal deflection circuit (1, 2, 4), a feedback circuit (4) is provided. This feedback circuit (4) processes the scan and/or fly-back voltages (Vsca, Vfly) to a control voltage (Vco) with which a duty cycle (dc) of a drive signal (Hdr) of a switching element (Tr) in the horizontal output stage (1) is influenced.

Abstract: An automatic beam current control circuit for a multimode monitor provides a high voltage circuit for regulating its output voltage according to a video signal being applied to a cathode ray tube, a luminance data compensator having an analog-to-digital (A/D) conversion port for receiving the output voltage of a feedback signal from the high voltage circuit and using a microprocessor to compare data converted by the analog-to-digital (A/D) conversion port with reference luminance data stored in a memory to thereby output an automatic beam current control value, and an automatic beam current controller for receiving the automatic beam current control value and automatically adjusting beam current provided to the cathode ray tube.

Abstract: In order to reduce power losses and to protect and thus to increase the service life of a vacuum-tube picture screen device with a stand-by function, the heating current (Ih) of the picture tube heater (Hh) is reduced and the deflection device (VA, HA) belonging to the picture tube (BR) and the video amplifier (VV) are switched off. At the same time, the cathode (K) and a predetermined electrode (G2) of the picture tube (BR) are supplied with a predetermined energy. In pauses between applications, a significant power reduction results while the instantaneous-picture function is retained and the risk of cathode poisoning is eliminated.

Abstract: A novel off-line bootstrap startup circuit (10) including a high voltage device (100) for providing an initial bias voltage to an integrated circuit (IC) is provided. The high voltage device includes an NMOS transistor (102) having a high source to ground breakdown voltage thereby extending a bias voltage range provided to the IC. This bias voltage range may be needed to support large comparator (303) hysteresis and allow for an unregulated bias voltage. The bootstrap startup circuit becomes inoperative when the bias voltage exceeds a predetermined value.

Abstract: Deflection apparatus for a raster scanned cathode ray tube display comprises a flyback circuit (T2,T4,Ly,Df,Cf) including a switch (T2,T4) connected in series with an inductor (Ly). The switch (T4) is responsive to a line drive signal (LINE) to alternately open and close a current path through the inductor (Ly) between a first voltage level (B+) and a second voltage level (0V) lower than the first voltage level (B+) to generate a raster scan current signal in a deflection coil of the display. The amplitude of the raster scan signal is determined as a function of the first voltage level (B+) and the frequency of the line drive signal (LINE). A feedback circuit (D2,R3,D3,C2) connected to the switch (T4) generates a feedback signal (F) as a function of current flowing out of the switch (T4).

Abstract: A fly-back transformer for generating a focus voltage to be applied to a cathode-ray tube, includes an iron core, a primary coil, a D.C. voltage generating circuit, and a superimposing circuit. The primary coil is wound on the iron core for receiving a pulse voltage generated during a fly-back period of a horizontal sweep signal for the cathode-ray tube. The D.C. voltage generating circuit includes at least one secondary coil wound on the iron core, for generating, in response to the pulse voltage, a D.C. voltage. The superimposing circuit generates a parabolic-wave voltage from a voltage taken out from one of the at least one secondary coil, and superimposes the parabolic-wave voltage on the D.C. voltage to generate the focus voltage. Alternatively, the superimposing circuit generates a parabolic-wave voltage from a voltage taken out by a third coil wound on the iron core, which has one end connected to an end of the at least one secondary coil.

Abstract: A deflection apparatus for a raster scanned cathode ray tube display, the apparatus comprising: a ramp generator having a flyback circuit including a first inductor connected in series with a first transistor switch, the first transistor switch being responsive to a line drive signal to alternately open and close a current path through the first inductor between a first voltage level and a second voltage level lower than the first voltage level to generate a raster scan current signal in a deflection coil of the display, the amplitude of the raster scan current signal being determined as a function of the first voltage level and the frequency of the line drive switching signal, and a boost circuit connected to the flyback circuit, the boost circuit comprising a second inductor connected in series with a second transistor switch, the second transistor switch being responsive to a pulse signal synchronized to the line drive signal to alternately open and close a current path through the second inductor between

Abstract: A charge storage capacitor is coupled to an ultor electrode of a cathode ray tube for supplying a beam current when video loading variations occur. A relatively small resistor coupled in series with the capacitor develops an AC feedback signal that is indicative of beam current variations. The AC feedback signal developed in the resistor is coupled to a control input of a high voltage regulator in a negative feedback manner to compensate for the beam current variations. An ultor voltage is developed across a voltage divider. A DC feedback signal is coupled from a terminal of the voltage divider to the control input of the regulator. The DC feedback signal is low-pass filtered via a first low-pass filter. The AC feedback signal is low-pass filtered via a separate low-pass filter that provides less extensive low pass filtering than the first low-pass filter.

Abstract: Disclosed herein is a raster left-and-right distortions correcting apparatus for correcting left and right distortions of a raster. According to the raster left-and-right distortions correcting apparatus, parameters for correcting the left and right distortions peculiar to a CRT of the raster left-and-right distortions correcting apparatus are stored in an E.sup.2 PROM. The parameters are then electrically processed by a DSP. Thereafter, an analog voltage obtained by D-A converting the result of processing is supplied to a comparator. The comparator compares the analog voltage with a sawtooth wave voltage synchronized with a horizontal synchronizing signal. A switch is controlled depending on the width of a pulse on the basis of the result of comparison to thereby switch a power source for a horizontal output circuit.

Abstract: In a focus circuit for cathode-ray tube (40) of electromagnetic focusing type, a DC voltage (B4) which is made by dividing CRT anode voltage (B3) by a voltage dividing circuit (27) is compared with a reference voltage (B6) by an anode voltage variation component detection circuit (29), thereby to output therefrom a signal (Ve) of anode voltage variation component. This signal (Ve) and static focus adjusting DC voltage (B7) are summed and amplified by an output amplifier 30, which issues a current for correcting focus to electromagnetic focusing coil (31).

Abstract: A CRT protector circuit for detecting an overcurrent or an overvoltage to a CRT to protect the CRT. A detector circuit is provided for detecting the overcurrent and the overvoltage, and when such is detected an abnormality detection output from the detector circuit is supplied to a control circuit which in turn controls a horizontal output circuit. The operation of the horizontal output circuit, provided on a primary side of a flyback transformer is, instantaneously broken by the control circuit according to the abnormality detection output from the detector circuit. When the frequency of generation of the abnormality detection output becomes a predetermined value or more, the operation of the horizontal output circuit is continuously inhibited. Accordingly, when the abnormal condition is temporary, a normal high-voltage generating operation can be automatically restored.

Abstract: In a horizontal deflection circuit output stage, a retrace pulse voltage is developed in a primary winding of a flyback transformer and transformer-coupled to a secondary winding and rectified for developing a high voltage. A portion of the transformer-coupled rectified voltage is combined in a voltage divider with a second rectified voltage. The second rectified voltage is produced in a peak rectifier from the retrace pulse voltage in the primary winding in a manner that bypasses the secondary winding. A screen grid voltage is developed at a terminal of the voltage divider. A change in beam current loading produces variations in opposite sense in the combined rectified voltages in a manner to regulate the screen grid voltage.

Abstract: A display apparatus for displaying pictures virtually instantaneously adopts a direct-heating type cathode of an impregnated structure, and includes a cathode ray tube having a dispenser cathode wherein a cathode material is filled in pores of a porous body and a porous heater is directly connected to the cathode material. A voltage generator of the apparatus produces a first voltage for driving the heater. A video signal supply portion supplies a video signal to the cathode, while a deflector deflects horizontally and vertically an electron beam generated from the cathode to produce a raster by scanning the fluorescent surface of the cathode ray tube. A flyback transformer generates a second voltage to be supplied to the anode and one or more grids of the cathode ray tube using a horizontal deflection output signal supplied from the deflector. With the described arrangement, an electron-emitting velocity of an electron gun reaches its maximum value within about one second after power is applied.

Abstract: A circuit for synchronizing an operating clock of a switching power supply (SPS) system is provided. The SPS has an oscillator, a primary control circuit, a secondary voltage generation circuit, a feedback control circuit. The oscillator outputs an oscillation signal to the primary control circuit. The feedback control circuit, in response to a direct current (DC) voltage from the secondary voltage generation circuit, generates a DC feedback voltage signal. The synchronization circuit comprises an isolation device, a signal separation circuit and a triangle-wave generation circuit. The isolation device has an input terminal and an output terminal. The input terminal receives a horizontal synchronization signal and the DC feedback voltage signal. A mixed signal is generated at the output terminal as a result of amplitude-modulating the DC feedback voltage signal by the horizontal synchronization signal. The input terminal is voltage-isolated from the output terminal.

Abstract: Deflection apparatus for a raster scanned cathode ray tube display comprises a ramp generator (210) for producing a current ramp signal synchronised to a raster synchronisation signal. A ramp regulator (230) is connected to the generator (210) for varying the amplitude of the scan signal as a function of the difference between a reference input and a feedback signal. A feedback circuit (220) connected to the generator (210) and to the regulator (230) for generating the feedback signal as a function of the amplitude and frequency of the line scan signal. A multiplier (250) is connected to the regulator and for varying the reference input as a function of an integer multiple of the frequency of the raster synchronisation signal. Any scan signal frequency component in the feedback signal is cancelled at the input to the regulator by introducing, via the multiplier (250), a scan signal frequency component to the reference input.

Abstract: A first resonant retrace circuit is operable for generating a first voltage signal and a second resonant retrace circuit coupled to the first resonant retrace circuit is operable for generating a second voltage signal summed with the first voltage signal. An auxiliary winding of a flyback transformer in the first resonant retrace circuit generates a first feedback pulse signal representative of the first voltage signal. A regulator senses the summed first and second voltage signals and generates a second feedback pulse signal representative of the summed first and second voltage signals. The second resonant retrace means is responsive to the regulator. A resistive summing junction combines the first and second feedback pulse signals to generate a composite feedback pulse signal. A voltage level is generated indicative of the energy in the composite feedback pulse signal.

Abstract: A full wave rectified AC mains supply voltage is produced from an AC mains supply voltage without low-pass filtering. The rectified voltage is developed in a winding of a flyback transformer. The winding of the flyback transformer is also coupled to a switching transistor that generates in the winding a first plurality of current pulses at a frequency that is higher than the frequency of the mains supply voltage. The current pulses energize a load circuit. A capacitor voltage is coupled via a second switching transistor to the winding to produce in the winding a second plurality of current pulses that energize the load circuit during a portion of the period of the mains supply voltage that does not occur in the vicinity of the peak of the mains supply voltage. When the second plurality of current pulses are generated, the mains supply voltage is decoupled from the first winding.

Abstract: An East-West switching transistor is coupled between a flyback transformer primary winding and a horizontal deflection output transistor circuit to control retrace energy to obtain an East-West modulation of the deflection current amplitude as required for East-West pincushion raster correction. The East-West switching transistor isolates a retrace resonant circuit that includes a horizontal deflection winding from a flyback resonant circuit that includes the flyback transformer during a portion of retrace. The deflection winding is coupled to a common conductor to permit the use of a retrace voltage sample, developed in the deflection winding and coupled to the East-West switching transistor, to control the switching operation in a manner that bypasses the flyback transformer. A resistor coupled in series with the primary winding develops a voltage, during trace, that is indicative of beam current.

Abstract: An improved regulated flyback high DC voltage output supply, particularly adapted for providing the anode voltage to a CRT, includes a flyback transformer having its output winding connected to a improved regulator of the type including a string of transistors used to provide a correction signal for stabilizing the output of the supply. The regulator also includes a plurality of Zener diodes, each connected in parallel with a corresponding one of the transistors for providing surge protection for the transistors and for providing an alternate current path to the corresponding transistor, depending on the level of the correction signal.

Abstract: A flyback transformer for use with a horizontal sweep circuit and a CRT. The transformer includes a first "U-shaped" magnetic core member having first and second legs and a second "U-shaped" magnetic core member having first and second legs. The first legs of the first and second core members are spaced apart to form a gap therebetween, and the second legs of the first and second core members have planar faces that are in parallel abutting relationship with each other when the transformer is in an assembled relationship. Coil windings surround the gap and a portion of each of the first legs when the transformer is assembled.

Abstract: A distributed power system for providing multiple output voltages, including pulsed voltages, to a solid-state phased-array radar transmit/receive module, for example, includes: an energy-storage capacitor for coupling to an input dc power source and for storing substantial energy at high voltage for supplying pulsed voltages at low voltage; at least one capacitance-multiplying converter, including first and second transformers with multiple secondary windings, for producing positive and negative voltages on buses internal to a power module; and a plurality of series regulators to obtain multiple positive and negative load voltages, including pulsed voltages, from the positive and negative bus voltages. Substantial energy storage is achieved within the power module; and, if even more energy storage is desired, an additional external energy-storage capacitor can be coupled to the input power leads, thereby being coupled in parallel with the energy-storage capacitor.

Abstract: A deflection and high voltage circuit produces a proper luminance level and a focusing performance in a CRT image irrespectively of changes in a luminance signal level. The circuit is provided with a voltage control circuit for controlling an output voltage level of a voltage supply circuit according to changes in the anode voltage of the CRT so that a voltage obtained by rectifying a voltage generated by the secondary winding of flyback transformer, i.e., the anode voltage of the CRT is made constant. Furthermore, the circuit is provided with a correction circuit for preventing a voltage across the terminals of a S-curve correction capacitor determining the H-size of the CRT image from being affected by the variation of the output voltage level of the voltage supply circuit.

Abstract: A power supply for a television apparatus, comprises a first source of unregulated DO run voltage operable only in a run mode of operation and a second source of unregulated DO voltage operable in a standby mode and in the run mode of operation. A first regulator responsive to the first source unregulated DO run voltage produces a first regulated voltage. A second regulator responsive to the second source of unregulated DO voltage produces a second regulated voltage. First and second integrated circuits are energized respectively by the first and second regulated voltages. At least one of the integrated circuits has a signal output coupled to a signal input of the other of the integrated circuits. A controller is operable in the run mode and responsive to variations of one of the regulated voltages for adjusting the other of the regulated voltages to follow the variations. Each of the regulators may comprise a series pass transistor and a control transistor coupled to a base of the series pass transistor.

Abstract: A first transformer is coupled to a deflection yoke and coupled to a derived secondary voltage source for driving a load, for example, for generating an ultor voltage. An on/off switch is responsive to an on/off signal. A second transformer has a primary winding coupled to the switch and coupled to a voltage source and has a secondary winding coupled to the first transformer. A first sampling circuit generates a first feedback signal indicative of current flowing from the secondary winding to the first transformer. A first safety circuit responsive to the first feedback signal controls the effect of the on/off signal on the switch when the current flowing from the secondary winding to the first transformer exceeds a threshold, by limiting the on time of the switch to limit the peak value of the current. A second sampling circuit generates a second feedback signal indicative of the ultor voltage.

Abstract: The horizontal output stage of a television receiver is tested by denergizing the receiver so as to remove B+ voltage from the horizontal output stage, and then powering the horizontal output stage from an independent low voltage DC power supply through a switch which is turned on and off at the horizontal sweep frequency to permit making measurements of operating parameters of said horizontal output stage.

Abstract: A pulse-width modulator controls a switching transistor. The switching transistor is coupled to a primary winding of a chopper transformer. The switching transistor and the primary winding are referenced to a nonisolated ground conductor. To initiate a standby mode of operation, a first on/off control signal that is referenced to an isolated ground conductor disables a horizontal oscillator that is energized from a secondary winding of the chopper transformer and that is also referenced to the isolated ground conductor. As a result, a decrease loading of circuit elements that are referenced to the isolated ground occurs. In the standby mode, current pulses in the primary winding are produced at a substantially higher frequency than in normal operation. A frequency detector referenced to the nonisolated ground generates a second on/off control signal that is referenced to the nonisolated ground in accordance with the frequency of the current pulses in the chopper transformer.

Abstract: In a switch mode power supply, a full wave rectified AC mains supply voltage is produced from an AC mains supply voltage without low-pass filtering. The unfiltered rectified voltage is applied to a winding of a flyback transformer that is coupled to a switching transistor. A first plurality of current pulses are generated in the winding from the rectified voltage at a frequency that is higher than the frequency of the mains supply voltage and at peak amplitudes that vary in a manner to reduce a power factor. A second supply voltage is applied via a second switching transistor to the winding to produce in the winding a second plurality of current pulses that reduce a ripple component at an output of the power supply. The second plurality of current pulses are pulse-width modulated in a feed-forward manner during a period of the mains supply voltage in accordance with the mains supply voltage.

Abstract: In a switch mode power supply, a full wave rectified AC mains supply voltage is produced from an AC mains supply voltage without low-pass filtering. The unfiltered rectified voltage is applied to a winding of a flyback transformer that is coupled to a switching transistor. A first plurality of current pulses are generated in the winding from the rectified voltage at a frequency that is higher than the frequency of the mains supply voltage and at peak amplitudes that vary in accordance with the rectified voltage in a manner to increase a power factor. The rectified voltage is further rectified via a rectifier coupled in series with a resistor and a low-pass filter capacitor and produces current pulses in the capacitor. A voltage in the capacitor is coupled via a second switching transistor to the winding to produce in the winding a second plurality of current pulses that reduce a ripple component at an output of the power supply.

Abstract: An EHT power supply, for example for a cathode ray tube, having a voltage multiplier of a multi-stage Cockroft-Walton type, in which the capacitors of each stage are formed by layers of conducting material juxtaposed on either side of a layer of dielectric material, the layers of dielectric material forming an integral part of the mechanical structure of the multiplier and physically supporting the rectifier diodes of the multiplier. In one embodiment of the invention, the multiplier is formed as a closely-spaced stack in which each stage comprises a separate layer of dielectric material, and in another embodiment the capacitors of the AC side of the multiplier are formed on one layer of material and the capacitors of the DC side of the multiplier are formed on another layer, the two layers being disposable on opposite sides of the neck of a cathode ray tube with the successive stages being longitudinally disposed along the neck.

Abstract: A coil (11) is connected in series to a primary winding (1a) of a flyback transformer (1). A series circuit of a capacitor (15) and a switching circuit (12) is connected in parallel to the coil (11). By turning on and off the switching circuit (12), the connection of the capacitor (15) to the coil (11) is switched, to thereby connect or disconnect the coil (11) in an AC fashion. Therefore, it is possible to realize a high voltage regulating circuit which can be made inexpensive.