Abstract: A gate driver circuit comprises a sensor, an amplifier, a regulator and a gate driver. The sensor is configured to sense a collector-emitter voltage and includes a first resistor and a second resistor connected in series, a high voltage diode connected between the series connected first and second resistors and a first capacitor connected parallel to the second resistor. The amplifier is configured to amplify a sensor output voltage and includes a non-inverting operational amplifier controlled by means of a plurality of resistors, a voltage follower connected to an output terminal of the non-inverting operational amplifier through a first diode and a third resistor connected across the first diode and the voltage follower. The regulator is configured to regulate a regulator output voltage based on an amplifier voltage. The gate driver is configured to connect/disconnect the regulator output voltage to the base terminal of the BJT.

Abstract: A drive circuit for a transistor component is described. The drive circuit comprises: an output, which is designed to be connected to a drive input of a transistor component and which has a first output node and a second output node; an input, which is designed to receive an input signal, which is referred to a reference potential, and which has a first input node and a second input node; a differential amplifier arrangement, which is connected to the first input node, the second input node, and the second output node, and which is designed to generate a drive signal based on the input signal; and a driver circuit, which is designed to receive the drive signal and to generate a drive voltage between the first and second output node based on the drive signal.

Abstract: A method for detecting high-frequency AC currents in a DC circuit including a common mode choke with two partial windings includes tapping voltages dropping across the two partial windings due to the AC current, superposing the tapped voltages, and obtaining a superposed AC voltage wherein differential mode portions of the tapped voltages are summed constructively and common mode portions of the voltages are summed destructively; and measuring the superposed AC voltage.

Abstract: A power detecting circuit for a power supply module is disclosed. The power detecting circuit includes a current detecting module, a micro control unit (MCU), a correcting circuit. The current detecting module is electrically coupled to the power supply module and configured to detect an output current value of the power supply module. The micro control unit (MCU) is electrically coupled to the current detecting module. The correcting circuit is electrically coupled to the MCU and configured to correct the output current value of the power supply module. The MCU is configured to calculate an output power value of the power supply module according to the output current value and a preset output voltage value or a tested output voltage value of the power supply module and display the output power value via a display module.

Abstract: A light emitting system includes a light emitting device having a forward voltage, and an optical power control device. The optical power control device includes a control signal module and a current controller. The control signal module generates a control signal according to the forward voltage, and the current controller permits flow of a driving current through the light emitting device according to the control signal.

Abstract: A switching power supply includes a first auxiliary power supply for causing a first auxiliary winding of a transformer to induce voltage by ON/OFF control of a switching element connected to a primary winding of the transformer. The voltage induced by the first auxiliary winding charges a capacitor in the first auxiliary power supply. The switching power supply also includes a control circuit for starting and stopping the ON/OFF control of the switching element by comparing a voltage of the capacitor with a first threshold value, an activation circuit for charging the capacitor with voltage from the power supply input to the switching power supply, and a determination unit for determining a lifespan of the switching power supply based on the voltage of the capacitor after the voltage of the capacitor becomes greater than or equal to the first threshold value.

Abstract: In a light source inverter rectifier circuits are respectively connected to a CCFL in a substantially U-shaped lamp and a CCFL in a substantially U-shaped lamp, and the outputs from the rectifier circuits are fed to a stabilization circuit. Thus, the stabilization circuit monitors an average of currents flowing through the substantially U-shaped lamps. This makes it possible to make uniform the currents flowing through the substantially U-shaped lamps.

Abstract: A cathode ray tube display apparatus having a fly back transformer (FBT) to induce and output high voltage, the CRT apparatus including: a power controller controlling source power input into the FBT; a DC power detector to output a shut-off signal to shut off an operation of the power controller if the DC power detector is supplied with a direct current signal. The CRT display apparatus provides for normal operation of a system while protecting circuit components from abnormal operation of the system.

Abstract: An image distortion correction apparatus is disclosed which can correct misconvergence using a D-class amplifier. The image distortion correction apparatus has an image processor for detecting an image signal and horizontal/vertical synchronous signals from a signal received from an external source; a distortion value calculator for calculating a misconvergence value occurring when the image signal is scanned based on the horizontal/vertical synchronous signals; a correction value calculator for calculating a convergence correction value of a pulse waveform to correct misconvergence of the image signal based on the misconvergence value; an amplifier for performing a D-class amplification with respect to the convergence correction value; and a convergence yoke fixed to a cathode ray tube (CRT) for controlling a path of an electron beam corresponding to the image signal based on the convergence correction value amplified in the amplifier.

Abstract: A control circuit for use in a video processor utilizes combined automatic kinescope bias (AKB) control, and average individual beam current sensing and limiting in at least one CRT. The control circuit includes automatic kinescope bias (AKB) control circuitry for detecting a magnitude of individual red (R), green (G) and blue (B) cathode currents driving corresponding R, G and B CRTs, generating R, G and B average cathode current control signals therefrom, and using the R, G and B average cathode current control signals as feedback to the video processor to reduce the R, G and B cathode currents approximately equal current amounts.

Abstract: An image distortion compensating apparatus controls a convergence yoke, and includes a compensation value generator for calculating a convergence compensation value for compensating a convergence distortion which occurs while an image signal is emitted onto a display apparatus, the compensation value generator outputting the convergence compensation value after compensating for a phase and a gain of the convergence yoke; an amplifier for D-class amplifying of the convergence compensation value; and a convergence yoke attached to the display apparatus for controlling a path of electron beams corresponding to the image signal, based on the convergence compensation value as amplified at the amplifier.

Abstract: A control circuit of a power supply delivering a supply current to an inductor connected in series with the horizontal deflection yoke of a cathode ray tube display, the inductor being the primary coil of a transformer operatively connected for delivering a rectified low-pass filtered biasing voltage to the anode of the display, the low-pass filtering having a first time constant corresponding to the duration of a plurality of pictures, the control circuit having feedback circuitry for generating a monitoring voltage substantially proportional to the biasing voltage and for controlling the supply current to keep the monitoring voltage equal to a reference voltage; and feedforward circuitry for measuring the cathode current and for adding to the monitoring voltage a compensation voltage corresponding to the cathode current, low-pass filtered with a second time constant corresponding to the duration of a small number of lines and high-pass filtered with the first time constant.

Abstract: A line scan circuit for a CRT, including, in series across a switch, two oscillating circuits having the same time constant, each including, in parallel, a capacitor, a diode connected in antiparallel, and a series association of an inductor and of a voltage source, the inductor of a first one of the oscillating circuits being a scan coil of the CRT; an amplifier receiving a set-point voltage and using, as a feedback, a voltage taken from one of the oscillating circuits, and providing an adjustable voltage source to the second oscillating circuit.

Abstract: In accordance with an exemplary embodiment of the present invention, a cathode ray tube convergence circuit includes a low voltage power supply and a high voltage power supply. The cathode ray tube convergence circuit further includes a switching network which is adapted to switch between the low voltage power supply and the high voltage power supply. The switching network dissipates substantially no power during operation of the convergence circuit.

Abstract: A display system (10) which includes a CRT feedback current simulating circuit (20) to simulate the cathode feedback current directly from the from the red, green and blue output biases of the video processor (13). Furthermore, the display system (10) applies blanking to the references pulses applied to the CRT output driving stage (16) so that the reference pulses will not be visible during a vertical underscanned condition. Shifting the generation of the cathode feedback current prior to the application of the blanking prevents any significant distortion, modification or skewing of the cathode feedback current sensed by the AKB sensing circuitry (19) of the video processor (13).

Abstract: A circuit for driving a cathode ray tube (CRT) with cathode current detection. Specifically, the present invention discloses a CRT driver circuit comprising a push-pull configuration comprising upper and lower stages of darlington paired transistors. In the lower stage, a lower prestage circuit generates a video output signal in response to a video input signal that is amplified to drive a cathode electrode of a coupled CRT. In the upper stage, an upper prestage circuit of transistors drives a voltage divider for splitting a high voltage supply between the transistors in the lower prestage circuit. In both the upper and lower stages of darlington paired transistors, upper and lower output stages of transistors are electrically active only during transient periods of the video input signal. As such, a cathode current from a static test signal can be measured from an output through the lower prestage circuit.

Abstract: An image input device includes a turn-on circuit and a converting circuit for receiving light reflected at an object and converting it into an electrical signal. The image input device is connected to a laser device as an output device. The turn-on circuit includes a triangular wave generating circuit, an error amplifier, a pulse width modulator, a lamp turn-on circuit, a xenon lamp and a protection circuit. The converting circuit includes an oscillator, a system control unit having a microprocessor to control the whole image input device, and image sensors. A same clock having a certain frequency from the oscillator is supplied to the turn-on circuit and the system control unit in the converting circuit thereby controlling the turn-on circuit to synchronize with driving signals of the image sensors.

Abstract: A shadowmaskless tracking cathode ray tube control circuit is described, comprising a control loop, which is coupled to a deflection unit of a shadowmaskless tracking cathode ray tube. The shadowmaskless tracking cathode ray tube control circuit further comprises a loop gain control means for compensating the loop gain of the control loop in dependence on the inverse value of the beam current in the shadowmaskless tracking cathode ray tube. The effect is that a constant loop gain is created, which is independent of the beam current.

Abstract: A primary winding of a transformer is serially connected to a horizontal deflection coil. An amplitude regulating circuit outputs a first correction voltage in response to a voltage generated on a secondary winding of the transformer. A phase regulating circuit regulates the phase of the first correction voltage output from the amplitude regulating circuit and outputs a second correction voltage. An addition circuit adds the second correction voltage to a sawtooth wave voltage generated by a sawtooth wave voltage generation circuit. A correction current output from an amplifier in response to the second correction voltage output from the phase regulating circuit cancels a current component generated on a vertical deflection coil by a horizontal deflection current.

Abstract: The present invention relates to a picture display device having a cathode ray tube (2), control means (50) for controlling the electron beam/beams of the cathode ray tube (2), an indexing element (12, 14) for determining whether the electron beam/beams impinges at the correct location, and a feedback system for providing the control means (50) with a signal generated by the indexing means (12,14). The feedback system comprises a level shifter (30) for transferring the signal from a high-voltage system (20) of the cathode ray tube and the indexing elements (12, 14) to a low-voltage system (22) of the control means (50). In order to provide the level shifter (30) with the capacity of transferring signals comprising high frequencies, the level shifter (30) is provided with an input stage (32a, 32b) arranged to decrease the input impedance of the level shifter (30).

Abstract: A tracking index cathode ray tube circuit includes a tracking circuit connected to a shadowmaskless tracking cathode ray tube for deriving a tracking signal therefrom. The tracking circuit comprises a modulator demodulator circuit. The tracking signal from the CRT tube is thus modulated, AC coupled to a low voltage and demodulated to obtain a baseband tracking signal for use as a control signal for the electron beam spots on the screen of the CRT tube.

Abstract: An electronic circuit for switching an inductive load (10) by way of a bipolar transistor (1) whereby a switching signal is supplied to the base (5) of a switching transistor (1) via an LRC circuit (6, 7, 9). During switching off the LRC circuit (6, 7, 9) causes a peak voltage at the base (5) of the switching transistor (1). The value of the peak voltage is a maximum when the power dissipation of the switching transistor (1) is a minimum. A regulator circuit (12-17) regulates a current source (18) in a primary winding of a switched transformer (22) in such a way that the peak voltage (Vp) is maximized.

Abstract: A CRT display apparatus is disclosed. The CRT display apparatus includes a CRT having an electron gun whose electrodes for controlling an electron beam are applied with voltages from their respective voltage sources specifically designed to supply an electrode current, and is capable of automatically ceasing a discharge that has occurred under fault conditions between any electrode within the electron gun and the cathode or an anode of the CRT.

Abstract: In an arrangement for coupling out an output current from a load current by a load (2), particularly a deflection coil of a cathode ray tube by means of an output resistor (4), which arrangement comprises an output current mirror (9, 10, 11), in which a control value in the form of the difference between two voltages dropping across two resistors (35, 36) for controlling the load current is generated and in which a reference current bank (12) is provided with a current mirror circuit whose input receives a constant current for generating constant currents, a minimal temperature dependence is obtained in that the output current is coupled to the emitter of at least a first output transistor (10) and at least a second output transistor (11) of the output current mirror, in that the reference current bank (12) supplies a first reference current which, together with the output current, is coupled to the emitter of the first output transistor (10) and the second output transistor (11) of the output current mirror,

Abstract: A CRT display apparatus is disclosed. The CRT display apparatus includes a CRT having an electron gun whose electrodes for controlling an electron beam are applied with voltages from their respective voltage sources specifically designed to supply an electrode current, and is capable of automatically ceasing a discharge that has occurred under fault conditions between any electrode within the electron gun and the cathode or an anode of the CRT.

Abstract: A CRT driving voltage generating apparatus which can be realized and integrated at low cost, and can prevent breakdown and malfunction of circuits by actively adapting to a change in the frequency of a horizontal synchronous signal, and a CRT driving voltage generating method performed by the apparatus are provided. In this apparatus, a first comparator compares a reference value with the peak value of a fly back pulse. A stability controller shifts the level of the result of the comparison using a current mirroring technique and outputs a compared signal having a shifted level. A second comparator compares the compared signal with a sensing signal to obtain a reset signal. A pulse width modulated signal generator outputs a pulse width modulated signal having a level which is determined in response to the logic levels of a clock signal and a reset signal. A driving voltage generator generates the CRT driving voltage in response to the pulse width modulated signal.

Abstract: A Braun tube discharge apparatus that includes a so-called spot killer function. In the apparatus, an operational amplifier included in a vertical IC receives a vertical ramp signal from a one-chip IC at the non-inversion input terminal. The operational amplifier also receives a part of the output as a negative feedback to the inversion input terminal, and performs differential amplification of it and transmits the results to a vertical deflection coil. At the time a spot killer circuit discharges a remaining electrical charge held by a Braun tube when the power is turned off, a switching transistor is rendered conductive by using a spot killer pulse signal that instructs the activation of the spot killer circuit. When the negative feedback input side of the operational amplifier drops to the ground level, the center DC value of the vertical output signal is increased, and the amplitude is increased.

Abstract: The present invention relates to an apparatus and a method for saving electric power in a display system in which, when the display system is turned to an off mode, a total electric power consumption is reduced to a range for the display system to be operated through a reduction of an on-duty time period of a PWM pulse by using a charging/discharging device of a large capacitance. The present invention provides an ultra electric power-saving mode for a display system when the display system is turned into an off mode with no input of the horizontal and vertical synchronization signals from a video card of the computer main body to the display system. It accomplishes this by reducing the total electric power consumption by approximately half compared to the existing off mode performance through a remarkable reduction of the on-duty time of a PWM pulse to a range of supplying an operational voltage of the microcomputer with the use of a charging/discharging device of large capacitance.

Abstract: A shadowmaskless tracking cathode ray tube control circuit is described, comprising a control loop, which is coupled to a deflection unit of a shadowmaskless tracking cathode ray tube. The shadowmaskless tracking cathode ray tube control circuit further comprises a loop gain control means for compensating the loop gain of the control loop in dependence on the inverse value of the beam current in the shadowmaskless tracking cathode ray tube. The effect is that a constant loop gain is created, which is independent of the beam current.

Abstract: A wide band horizontal size regulation circuit of a display, is selectively switched according to input frequency, to control the amount of current transmitted to a current sensing port of a PWM IC. This circuit includes a microcomputer for generating a signal for regulating the horizontal size of a picture, a PWM-IC for generating a PWM signal for controlling the amount of current which flows through a horizontal deflection coil according to the control signal of the microcomputer, a current sensor for feeding back a current corresponding to a picture state to the PWM-IC in order to maintain a specific horizontal size, and a current controller which is selectively switched according to the control signal of the microcomputer, to control the amount of current fed back to the current sensor of the PWM-IC.

Abstract: An apparatus for image enhancement in a cathode ray tube display comprises an amplifier for a scanning velocity modulating signal. The scanning velocity modulating signal has an AC component and a DC value. A feedback circuit is responsive to power dissipation in the amplifier for controlling the AC component and the DC value with a first control signal, and controlling only the DC value with a second control signal.

Abstract: Recent circuit concepts inject measurement lines, for cutoff and drive control of the cathode current, into each color channel during the vertical frame blanking period. Owing to the physically dependent exponential beam current characteristic profile as a function of the cathode control voltage VK, the exponent &ggr; of the characteristic profile and the ratio of two cathode components IK1 and IK2 may be used to form control reference values for cutoff and drive control, this process being started in each case from a fixed value of the exponent &ggr; or of the ratio of the two cathode currents IK1 and Ik2. However, it has been found that, if a fixed value is assumed for the exponent &ggr; or for the ratio of the two cathode currents IK1 and IK2, it is not possible to achieve an optimum result for displaying monochrome pictures. Thus, according to the invention, the exponent &ggr; is defined as a function of the color tube 1. The aim in this case is to reduce a &ggr;-dependent DC voltage offset u0f to zero.

Abstract: An image display device has a plurality of electrodes that control a beam between a group of linear cathodes (2) and a screen (8) with a phosphor layer, and is provided with a circuit (31) for generating a beam track offset signal, which generates a signal for slightly oscillating one of the beams horizontally, a PIN photodiode (33) for detecting the emission amount of the phosphor layer for this beam, a comparator (35) for generating a beam irradiation position misalignment signal based on the detected emission amount, an integrating circuit (36) for generating a beam position control signal in correspondence with the beam irradiation position misalignment signal; and a horizontal deflection electrode driving circuit (39) for driving a horizontal deflection electrode (6) in accordance with the beam position control signal.

Abstract: A circuit fixedly limits the horizontal image size of a screen of a CRT display. The circuit for limiting the horizontal image size of the screen detects a voltage indicative of the horizontal image size of the screen with power provided to a horizontal output unit by a field effect transistor in a horizontal output power supply unit. A current mirror circuit coupled to the field effect transistors outputs current which flows into the drain of a field effect transistor when the field effect transistor is turned on. The outputted current is transformed into voltage and the voltage is fed back to the PWM control circuit to limit the horizontal image size of the screen.

Abstract: A raster distortion correction and deflection circuit arrangement includes a deflection coil adapted to be mounted on a cathode ray tube, a horizontal deflection coil driving circuit for passing a current of saw-tooth waveform of a horizontal deflection period through a horizontal deflection coil constituting the deflection coil, a flyback transformer the primary winding of which is connected between a power supply and an output terminal of the horizontal deflection coil driving circuit, an S-correction capacitor connected in series with the horizontal deflection coil, and an anode voltage detection circuit for detecting variations in an anode voltage of the cathode ray tube which is a secondary winding output of the flyback transformer. A raster distortion correction current based on an output voltage of the anode voltage detection circuit is injected into a connection point of the horizontal deflection coil and the S-correction capacitor.

Abstract: A horizontal size regulation circuit of a horizontal deflection circuit of a display device maintains a constant horizontal size despite transformer manufacturing tolerances, by using a horizontal flyback output value fed back from a choke coil of a horizontal output circuit. A voltage supplied to a switching element providing current to a horizontal output transistor is sensed according to the duty cycle output from a horizontal size controller. A voltage detector incorporated into the horizontal deflection circuit controls the value fed back to the horizontal size controller according to the variation of the voltage supplied to the switching element.

Abstract: A circuit for inhibiting a transition phenomenon in a power supply unit is disclosed. When the power supply mode is shifted, a transition phenomenon is made not to appear in the operating power supplied to the load. The circuit includes a microcomputer which judges as to the presence or absence of horizontal and vertical synchronizing signals supplied from the computer system so as to vary the power in a stepwise form when shifting the power supply mode. In accordance with control signals of the microcomputer, a feedback level adjusting section reduces the error detected voltage in a stepwise form when the power is fed back from a second rectifying section through an error detecting section to a pulse width modulator (PWM) control section. Therefore, in accordance with the stepwisely decreasing error detected voltage, the pulse width modulator (PWM) control section reduces its output signals in a stepwise form, so that the power supplied to the load can be reduced in a stepwise form.

Abstract: A series arrangement of a deflection coil (Lf) and a series resistor (Rs) is connected between an output of a first output amplifier (1) and an output of a second output amplifier (2) to be driven in a bridge configuration for generating a deflection current (If) through the deflection coil (Lf). Across the series resistor (Rs), a voltage is generated which corresponds to the deflection current (If). A differential amplifier (5) has a first input connected to a first end of the series resistor (Rs). A second input of the differential amplifier (5) is connected to a second end of the series resistor (Rs) via a conversion resistor (Rc). An input current (Ii) is generated through the conversion resistor (Rc). The polarity of the input current (Ii) is selected to obtain a voltage across the conversion resistor (Rc) which has an opposite polarity with respect to the voltage across the series resistor (Rs).

Abstract: An external magnetic field correction device capable of preventing malfunctions of the external magnetic field correction device due to operation of a degaussing circuit by judging that an abnormality has occurred when an output of an external magnetic field detector is not less than a predetermined value and interrupting offset adjustment process accordingly, and that is capable of limiting irregularities of offset current in operational current of the magnetic field correction device to predetermined value or less by adjusting an offset value as to make correction current to be supplied to an external magnetic field correction coil when an external magnetic field around a CRT is zero to a regular value or less.

Abstract: A deflection circuit generates a deflection current (If) through a deflection coil (Lf). The deflection circuit includes a series resistor (Rs) arranged in series with the deflection coil (Lf) to supply a feedback voltage (Vf;Vr), and a drive circuit (1,5) which has an output coupled to the series arrangement of the deflection coil (Lf) and the series resistor (Rs). The drive circuit (1,5) has an input coupled to the series resistor (Rs) to receive a feedback voltage (Vs). The drive circuit (1,5) further is coupled to a conversion resistor (Rc) for receiving an input waveform (Vi). The drive circuit (1,5) is arranged in a feedback loop to obtain a deflection current (If) with a shape resembling the input waveform (Vi). The deflection circuit further includes a damping impedance (Rd) arranged in parallel with the deflection coil (Lf), and a current generating circuit (3) for generating a correction current (Ic) within the flyback period (Tf).

Abstract: The turn-off period of the FET (111) is adjusted by changing the output pulse width of the MM (113) according to the horizontal deflection frequency, to adjust the total capacitance value of the S-shape correcting capacitor group in one horizontal deflection period, that is, to execute an optimum S-shape distortion correction according to each horizontal deflection frequency. The timing at which the electronic switch element (111) is turned off in a first half of the horizontal scanning period is continuously and variably controlled on the basis of an external control signal (Vg). The auxiliary S-shape correcting capacitor (110) of the S-shape correcting capacitor group is controllably turned on or off by the electronic switch element (111), to execute an optimum S-shape distortion correction.

Abstract: In a vertical sawtooth generator of a vertical deflection circuit, a first comparator generates an output signal when a retrace portion of a sawtooth signal is at a first magnitude to initiate a vertical trace portion of the sawtooth signal. An amplifier responsive to the sawtooth signal and to a reference signal generates a feedback current at a time that occurs between the center of vertical trace and the end of trace and away from the center of trace. The feedback current is determined in accordance with a difference between the sawtooth signal and the reference signal. The feedback current is coupled to a first capacitor to develop a gain control voltage. The control voltage is applied via a voltage-to-current converter to an integrating capacitor to develop in the integrating capacitor the trace portion of the sawtooth signal. The control voltage is initialized during a power start-up interval.

Abstract: A spot killer circuit for a CRT is capable of thoroughly removing any spot persistence and prevents damage to the fluorescent body of the CRT due to inaccurate horizontal and vertical deflection. When the power cord is unplugged, or when the display device is turned off (for example, via remote control key input), the bias voltage of the first grid G1 and the electric potential of the cathode are controlled so as to completely suppress any residual beam current flowing in the CRT. In the case of an inaccuracy (such as total failure) in either the horizontal deflection or the vertical deflection signals, the bias voltage of the first grid and the electric potential of the cathode are controlled to suppress the CRT beam current just as in the case of power shut off. This prevents damage of the fluorescent body in the CRT due to the inaccurate deflection operation.

Abstract: A horizontal retrace time adjustment pulse generating circuit includes a microcomputer for outputting a horizontal flyback signal and an analog voltage based on an input horizontal synchronizing frequency; oscillation duty adjusting circuit for outputting a duty-cycle adjusting signal based on the analog voltage of the microcomputer; a monostable multivibrator for outputting a rectangular wave based on the horizontal flyback signal of the microcomputer and the duty-cycle adjusting signal of the oscillation duty adjusting circuit; feedback signal detecting circuit for detecting a horizontal flyback pulse from a horizontal deflection circuit and outputting the detected signal; and signal coupling circuit for coupling the rectangular wave of the monostable multivibrator and the detected signal from the feedback signal detecting circuit and outputting a result of the coupling as a time control pulse for horizontal retrace.

Abstract: The line-sweep power circuit is of the known type, in which the base current of the switching transistor (TP) is automatically maintained by a positive feedback provided by a winding (L2) of the EHT transformer. This circuit is synchronized by a signal transmitted by an opto-coupler (DE-TC). The duty factor of the control signal transmitted by the opto-coupler is modified in a progressive manner during the transitions of a start signal (RC) so as to interrupt the conductance of the power transistor at an ever earlier instant. This may be obtained, for example, by means an integrator (4, 8) to which the load resistor (R2) of a transistor (T0) with an open collector is connected, which is driven by a line synchronizing signal.

Abstract: A horizontal deflection circuit includes circuitry for protecting the horizontal output transistor from failure due to an over-current condition. The circuitry includes a current detector for detecting the current in the collector-emitter path of the horizontal output transistor, and a interrupter for interrupting the drive signal to the horizontal output transistor when the detected current exceed a predetermined level.

Abstract: The electron gun with a field emission type cathode includes a substrate, a plurality of groups of cathodes disposed on the substrate, each group having a conically shaped electron-emitter, and gate electrodes each associated with each group of the plurality of groups of cathodes for causing the conically shaped electron-emitter to emit electrons by field emission. A control voltage can be applied independently to each group of the plurality of groups of cathodes, and also to the gate electrodes.

Abstract: In a vertical sawtooth generator, an end time of a retrace portion of a vertical sawtooth signal is controlled by an output signal of a comparator. The comparator has a first input terminal that is responsive to a reference voltage and a second input terminal that is responsive to the sawtooth signal. The reference voltage is coupled to an input terminal of an amplifier of an integrator that generates the sawtooth signal. Any disturbance signal component in the reference voltage is super-imposed on the sawtooth signal. Because the same disturbance signal component is developed simultaneously in both input terminals of the comparator, a high degree of common mode rejection is provided with respect to the disturbance signal component.

Abstract: A complementary push-pull emitter follower amplifier is coupled between the output of a high voltage driver amplifier and the cathode of a kinescope for reducing the effective capacitance presented to the driver amplifier that is attributable to the kinescope cathode, socket, spark gaps and related stray capacitances. A secondary undesired capacitance loading of the amplifier attributable to the collector to base capacitances of the follower amplifier is effectively reduced by regulating the collector emitter voltages of the push-pull follower output transistors at respective substantially constant values thereby improving parameters such as the slew rate and bandwidth of the overall video display system.

Abstract: A flat type CRT includes a horizontal deflection circuit and/or a vertical deflection circuit, in which order to prevent undesired zooming without using a high voltage regulator, reduce an amount of overscanning, and stabilize the picture, the deflection circuit is separated from a high voltage generating circuit, and a capacitor is provided between the high voltage generating circuit and the deflection circuit. The capacitor is arranged to provide a low voltage .DELTA.HV proportional to an anode voltage HV. This low voltage is added to the output of a transistor so that the level of the deflection voltage is varied.