Abstract: Devices and methods of forming an integrated circuit (IC) that offer protection against ESD in high voltage (HV) circuit applications are disclosed. A device includes N ones of a field effect transistor (FET) stacked in series to provide an N-level stack, where N is an integer greater than 1. A first pad of the device is coupled to a first FET and a second pad is coupled to an Nth FET. The device also includes a stacked/distributed RC control circuit configured to cause a short circuit between the first pad and the second pad in response to an ESD event. During the ESD event, the RC control circuit is configured to concurrently provide sufficient voltage to control the N ones of the FET by turning them on using parasitic conduction to cause the short circuit.

Abstract: A fluorescent lamp device includes a frequency generator for generating a pulse signal, a driver circuit coupled to said frequency generator for generating at least one driving signal according to said pulse signal, a half bridge power switch unit coupled to the driver circuit, a resonant tank coupled to the half bridge power switch unit, and a fluorescent lamp coupled to the resonant tank.

Abstract: A driving apparatus includes a DC-to-DC converter, a first LED series, a second LED series, a first constant-current circuit, a second constant-current circuit, and a feedback circuit. The DC-to-DC converter respectively outputs a direct-current voltage to one terminal of the first and the second LED series to generate a first potential and a second potential at the other terminal of the first and the second LED series according to a feedback voltage. The first and the second constant-current circuits are respectively coupled to the other terminal of the first and the second LED series and output a first current and a second current for driving the first and the second LED series according to a first and a second control signals. The feedback circuit uses the lower one of the first potential and the second potential as a feedback voltage.

Abstract: The invention concerns a control circuit for an electron tube display comprising a deflection coil, the deflection coil being part of a scanning circuit and being coupled to a coil of a transformer powering a high voltage generator used to accelerate an electron beam, a phase locked loop being used to keep in phase the flyback pulses produced by the scanning circuit and the video signal synchronisation pulses, and comprising an electron beam current measuring circuit, a compensation circuit for compensating the phase difference between the flyback pulses and the video signal synchronisation pulses as a function of the measured current.

Abstract: The invention includes: a capacitor 11 for generating ramp wave; a constant current source 10 for supplying constant current to the capacitor 11 for generating ramp wave; voltage fixing means for charging the capacitor 11 for generating ramp wave and for fixing a terminal of the capacitor 11 by force to a designated reference voltage Vref; and a counter circuit 15 enabling to output control signal having pulse width corresponding to desired waiting time, and that terminal voltage 17 of capacitor 11 for generating ramp wave is fixed to reference voltage while waiting time set by the counting circuit 15.

Abstract: The invention relates to a power supply (9) for a deflection circuit (1), that comprises a deflection coil (2) for connection to a picture tube, a drive circuit (4,5,6) connected to the deflection coil (2), and a deflection controller (3) for controlling the drive circuit (4,5,6). According to the invention the power supply (9) comprises a first input (10,11) connection to an output of the drive circuit (4,5,6) and the deflection coil, a second input connected to a power source (Vinput), a power supply output (13) connected to the drive circuit (4,5,6), and an adapter for adapting the power supply (VP) to the output (13) from the second input (Vinput) dependent on the first input (10,11).

Abstract: Disclosed is a device to control a circuit for the vertical deflection of a spot scanning a screen, and more particularly a control device whose output amplifier stage works in class D mode at the rate of a switching signal called a first switching signal. The control device has an internal auxiliary supply to generate the overvoltage needed for the fast flyback of the spot. This auxiliary power supply is a switching voltage generation circuit whose switching signal, called a second switching signal, is synchronous with the first switching signal. The present invention has been shown to used advantageously in television screens and/or computer screens.

Abstract: The control device includes an output amplifier stage ETS supplied by a main supply for controlling the vertical scan of the spot, and an auxiliary supply capable of delivering an overvoltage and a first two-way switch connected to the output stage and controllable to allow the overvoltage to be delivered to the vertical deflection circuit for flyback of the spot. The output stage is a stage having at least two transistors which are capable of operating in alternating switching mode, at least for control of the vertical scan of the spot, this stage being associated with a smoothing filter connected to the common terminal of the two transistors. The device includes a second two-way switch connected between a first transistor of the output stage and a first terminal of the main supply and controllable to prevent delivery of the overvoltage during control of the vertical scan of the spot.

Abstract: A magnetic deflection amplifier implemented using a linear amplifier connected to a first side of a deflection coil and a three pole switch connected to a second side of the deflection coil. The three pole switch connects the coil to ground during the active scan and connects the coil to a positive or negative high voltage rail depending of the polarity of the retrace current resulting in fast retrace time and reduced voltage requirements on the linear amplifier.

Abstract: The present invention relates to a proximity detecting device for detecting the presence of an object in a target area, comprising a low voltage power source, a circuitry for generating electrical pulses and supplying them to a light emitting diode (LED) in order to emit light pulses, and a receiver for reception of light pulses emitted from the LED and directed towards said target area, characterised in that said circuitry comprises a first circuitry containing a primary coil and switching means for connecting the primary coil for a period of time to said low voltage power source such as to accumulate a predetermined amount of magnetic energy in the primary coil, and a second circuitry containing said LED and a secondary coil magnetically coupled to said primary coil to transform the accumulated magnetic energy by mutual induction upon opening said switching means each time into one of said electrical pulses.

Abstract: A power amplifier circuit drives a load with a convergence correction current which is proportional to a convergence correction voltage waveform that is applied to the power amplifier circuit. A predriver stage of the power amplifier circuit comprises first and second transistors in a push-pull configuration. First and second voltage divider networks bias emitter electrodes of the first and second transistors, respectively, so that a common-mode current flow between the first and second transistors is limited. The first and second voltage dividers also protect the first and second transistors, respectively, from damage caused by thermal runaway.

Abstract: Scanning beam velocity modulation or SVM may be employed to produce subjective enhancement of picture sharpness. However, impulsive SVM deflection current may produce unwanted crosstalk into other circuitry thus a circuit configuration is disclosed where SVM currents are confined. An apparatus for electron beam deflection comprises a cathode ray tube having a scanning electron beam. A coil for supplementary electron beam deflection is mounted on the cathode ray tube. An amplifier is coupled between a supply of power and a return circuit and has an input coupled to a signal representing a video signal edge transition. The amplifier has an output which is coupled to the coil for generating a pulse current therein for electron beam deflection responsive to the signal. The amplifier and the coil are configured for circulation of the pulse current mainly within the coil and amplifier output without substantial pulse current flowing in the power supply and return circuit.

Abstract: This invention relates to a circuit for solving a vertical interlace phenomenon generated by the instability of servo control when a mode of VCR operation is fast or still, comprising a vertical pulse delay 101 for delaying a vertical pulse inputted from a vertical and horizontal oscillator 100 for the time of a certain horizontal lines, a vertical driving part which transforms the vertical pulse delayed from the vertical pulse delay 101 into a vertical a tooth wave pulse, and amends the transformed vertical a tooth wave pulse according to the vertical position signal inputted to be made relayed as a feedback, a vertical deflection amplifying part for amplifying the amended a tooth wave pulse inputted from the vertical driving part 102, a vertical position detecting part 105 for detecting a vertical position of a picture from the signal inputted from the vertical deflection amplifying part 103 through a vertical deflection coil 104, a Micom 106 for controlling an operation of the vertical pulse delay 101 and

Abstract: A vertical deflection circuit includes a first pin which receives a forward scanning voltage having a first level and a first frequency. During a flyback period a second pin receives a flyback voltage having a second level higher that the first level and a second frequency higher than the first frequency. A third voltage source provides a first pulse. A switch means selectively couples the first pin and the third voltage source in response to a vertical blanking signal. The vertical blanking signal is differentiated to provide a differentiated signal and a voltage divider applies the differentiated signal to the switch to apply the first pulse to the first pin.

Abstract: A differential amplifier formed by a pair of transistors couples a vertical sawtooth signal to an input side of a vertical deflection amplifier. Nonlinearity of the transistor pair provides S-correction in the vertical direction. The current in the transistor pair varies when vertical height is adjusted, in service operation, so that the nonlinearity changes. In a vertical shrink mode of operation, the amplitude of the sawtooth signal is reduced. The nonlinearity associated with a given level of the sawtooth signal that corresponds to a given vertical position in the vertical shrink mode is the same as that associated with the same level of the sawtooth signal in the vertical, non-shrink mode.

Abstract: The invention relates to a vertical deflection circuit of a cathode ray tube (CRT) using electromagnetic deflection. In the vertical deflection circuit, there is provided a pulse width varying unit for making both a vertical output transistor operated by a forward vertical deflection current and a transistor boosting-up during a vertical fly-back interval turn ON and OFF concurrently, in addition for adjusting an output pulse width from a circuit supplying a vertical blanking pulse to an image circuit. The pulse width is so adjusted that an initial portion of a vertical deflection is over-deflected thereby keeping a detection signal for an automatic white balance adjustment which is inserted immediately after the vertical blanking pulse from appearing on an under-scanned color CRT screen.

Abstract: Two windings of a flyback transformer in a horizontal deflection circuit are inductively coupled with opposite polarity to a source of horizontal rate retrace pulses. The windings have a common junction coupled to ground. A circuit energized by the retrace pulses generates modulated currents of opposite polarity. Conduction of each current is controlled by a switch circuit including a semiconductor switch and two diodes. The switch circuits are coupled to one another at a junction, and the junction is coupled to an energy storage capacitance. One of the diodes conducts positively valued portions of the respective current through the energy storage capacitance and the other of the diodes conducts negatively valued portions of the respective current through the semiconductor switch. Each semiconductor switch is a current discharge path.

Abstract: An special arrangement of the magnetic components of a horizontal sweep output circuit to reduce the net flux density and magnetic induction that are present at the exterior of a video display. The special arrangement meets the new, lower VLF electro-magnetic emission standards of some of the European countries, such as Sweden. The method used for obtaining this special arrangement of horizontal sweep output components is also disclosed.

Abstract: A display system is disclosed utilizing a cathode ray display device utilizing three electron beams which are directed through a shadow mask to excite three-color phosphor dots, and which is incorporated in a system to alternately provide raster scan display signals and calligraphic display signals to obtain the benefits of both raster scan and calligraphic displays (dot or line drawings). A deflection unit is disclosed with the X and Y deflection coils each driven by two pairs of transistor circuits. The transistor circuits are controlled so that alternatively one transistor in each set passes current to provide bi-directional currents at desired levels to obtain specific beam displacement. A resistive element between individual deflection coils provides an indication of deflection current, which indication is processed by a differential amplifier to indicate displacement. In accordance with the instant position of the beam, a convergence unit is controlled to reflect spherical considerations.

Abstract: A dual power source output amplifier comprises at least one pair of first and second input voltage sources of like polarity, operating at low and high voltage magnitude levels respectively relative to one another, and selectively operably coupled to an output stage for driving a load, for example a convergence yoke coil, in low and high voltage modes respectively. The first voltage input source is coupled to the output stage in the low voltage mode. A circuit for directly sensing the output voltage couples a biasing voltage level to the output signal for generating a high voltage demand control signal which varies directly with the output voltage. A switchable voltage regulator couples regulated high voltage from the second voltage input source to the output stage in the high voltage mode, responsive to the high voltage demand control signal. The output stage operates substantially linearly in both voltage modes.

Abstract: An electromagnetic deflection display system is operative for bi-directional raster and stroke deflection and provides minimum power dissipation in raster mode during a segmented or patch raster display. Energy stored in the deflection yoke during one direction of the raster scan is returned to an energizing power supply during the subsequent return scan in a manner that conserves power while avoiding an over-voltage condition of the associated power supply. A transformer is coupled to receive a portion of the energy stored in the yoke and return it to a designated raster mode power supply. The raster mode return voltage may be determined independently of stroke mode power requirements so as to optimize raster power savings and ampifier raster performance independent of the optimum stroke voltages.

Abstract: A bi-directional scanning system for a CRT is disclosed comprising: a vertical CRT deflection coil, a horizontal CRT deflection coil; two class-E switchmode amplifiers which are connected in a push-pull arrangement to convert a positive DC voltage and a negative DC voltage to a generally sinusoidal current for operating the horizontal CRT deflection coil; and a staircase voltage generator for operating the vertical CRT deflection coil.

Abstract: A vertical deflection circuit used in a cathode ray tube display device for shortening a vertical blanking period is disclosed which includes back-flow blocking diode means for preventing an oscillating current from flowing backward to a vertical push-pull output amplifier circuit in the vertical blanking period, resonating capacitor means, and electrostatic energy supplying means for energizing a fly-back pulse. The resonating capacitor means is provided to generate resonance due to the capacitance of the capacitor means and the inductance of a vertical deflection coil, on the basis of the electro-magnetic energy of the vertical deflection coil at a time immediately before a retrace line starts from the bottom of display screen, thereby producing a fly-back pulse. The back-flow blocking diode means prevents the fly-back pulse from flowing backward to the vertical output circuit, that is, prevents the fly-back pulse from de-energizing the output of the vertical output circuit.

Abstract: The circuit, particularly suitable for high-definition monitors, wherein a power amplifier is fed by a supply voltage source to generate a deflection current in a yoke, furthermore comprises switching means which are activatable to connect another source of a supply voltage higher than the source to the amplifier, and flyback detector means to activate said switching means at the beginning of the flyback.

Abstract: A solid-state switch in a deflection circuit includes a plurality of field-effect transistors (Q7, Q8, and Q9) connected in series. Each of the transistors (Q7, Q8, and Q9) is part of a switching module (20, 22, and 24) in the form of a three-terminal transistor circuit. Two of the modules (20 and 22) are connected to a common gating terminal (12) solely by diodes (D6 and D7) oriented so as (a) to conduct current in the direction required to provide a turn-on signal for the transistors (Q7 and Q8) but (b) to isolate the common gating terminal (12) from the high voltages experienced by the transistors (Q7 and Q8) when they are in their non-conducting states.

Abstract: A vertical deflection current generator includes an operational amplifier responsive to an input sawtooth signal at a vertical rate. A first end terminal of a deflection winding is coupled to an output terminal of the amplifier. A second end terminal of the deflection winding is coupled in series with a parallel arrangement of a switch and a capacitor. The switch is conductive during vertical trace. During vertical retrace, the switch is nonconductive that causes a vertical retrace voltage to develop in a flyback manner in the retrace capacitor. The retrace voltage in the retrace capacitor and a retrace voltage at the output terminal of the amplifier that are opposite in phase speed up the reversal of a deflection current in the deflection winding.

Abstract: A method and apparatus for the fast retrace of the electron beam in a cathode ray tube are disclosed. A deflection signal is presented to a cathode ray tube deflection system upon the detection of the end of the retrace period of the deflection signal so that a cathode ray tube electron beam can scan across the screen of the cathode ray tube. Upon detecting the beginning of the retrace period of the deflection signal, a forcing signal is presented to the cathode ray tube deflection system. The presenting of the forcing signal to the deflection system quickly reverses the direction of the current flow through the deflection system and allows for the electron beam to slew to its initial position and settle before the end of the normal retrace period.

Abstract: In a video display apparatus having a service mode of operation, a vertical deflection circuit includes a vertical deflection winding coupled to a DC blocking capacitor. An output stage is coupled to the vertical deflection winding at an output terminal. A vertical sawtooth voltage generator is coupled to a driver stage for driving the output stage at a vertical rate in a sawtooth manner to generate a sawtooth deflection current in the deflection winding and for establishing a DC operating voltage level at the output terminal that charges the DC blocking capacitor. The sawtooth generator includes a second capacitor that, during normal operation, is charged in a sawtooth manner via a resistor for developing a sawtooth signal. A service mode switching circuit is coupled to the resistor for asserting the service mode of operation by preventing the charging of the second capacitor via the resistor. A DC feedback loop maintains the DC blocking capacitor charged during the service mode.

Abstract: In a video display apparatus having an on-screen display feature (OSD), a vertical deflection circuit includes a vertical deflection winding coupled to a DC blocking capacitor. A deflection amplifier responsive to a sawtooth signal is coupled to the vertical deflection winding at an output terminal. A vertical sawtooth voltage generator that generates the sawtooth signal is coupled to an input terminal of the amplifier for driving the output stage at a vertical rate in a sawtooth manner to generate a sawtooth deflection current in the deflection winding. The sawtooth generator includes a capacitor that, during normal operation, is charged in a sawtooth manner via a resistor for developing a sawtooth signal. During a transition interval that follows a user initiated channel selection command, the frequency of the sawtooth signal becomes smaller.

Abstract: A vertical deflection circuit for a video display apparatus includes a service switch that collapses vertical or field rate scan in order to facilitate adjustment of cathodes ray tube electron beam drive levels. The service switch operates by referencing the vertical sawtooth signal generator, the AC feedback, and the DC feedback to ground potential so that no input is applied to the vertical drive circuitry.

Abstract: A vertical deflection circuit includes a vertical deflection coil; a vertical deflection circuit for supplying an vertical deflection current to the vertical deflection coil; a current multiplying circuit multiplying a predetermined current upon the current flowing through the vertical deflection coil in an even field or an odd field of a television signal; and the raster of the even field and the raster of the odd field coinciding with each other.

Abstract: A deflection amplifier for a CRT display device which generates a sweep ramp by means of a low distortion complimentary push-pull amplifier. The amplifier generates a compliance voltage which is fed back to an initial push-pull differential amplifier input stage and which is also used to generate a current through a deflection yoke coil. A sense resistor in series with the deflection yoke coil operates with a differential amplifier to direct a negative feedback signal to the input for the complimentary push-pull amplifier.

Abstract: A cathode ray beam deflection system operable in slew and random stroke and periodic raster display modes provides automatic power supply voltage switching to maintain linear operation and high efficiency. Control of automatic switching is obtained by continuously monitoring yoke voltage, yoke current, and deflection voltage, a power supply voltage being switched to a voltage of higher magnitude to provide a higher deflection rate when the yoke voltage exceeds a predetermined level at a predetermined current polarity and returned to a power supply voltage of lower magnitude when the higher deflection rate is no longer required.

Abstract: A vertical deflection amplifier of a video display apparatus includes first and second transistor amplifier output stages arranged in a totem-pole, push-pull configuration. A vertical deflection winding is coupled to the output stages at a deflection amplifier output terminal. An S-capacitor is coupled to the deflection winding at a second terminal remote from the output terminal. A source of deflection rate signals is coupled to the deflection amplifier for generating a deflection current in the deflection winding. A base current generating circuit is coupled to one of the transistor amplifier output stages for providing base current thereto. The S-capacitor voltage is applied to the base current generating circuit for enabling conduction of base current in the one amplifier output stage. When the video display apparatus is first turned on, the initially discharged S-capacitor is slowly charged from a DC voltage supply to delay generation of vertical deflection past completion of picture tube degaussing.

Abstract: In a video display apparatus having a service mode of operation, a vertical deflection circuit includes a vertical deflection winding coupled to a DC blocking capacitor. An output stage includes first and second output amplifiers coupled to the vertical deflection winding in a push-pull arrangement at an output terminal. A vertical sawtooth voltage generator is coupled to a driver stage via an error amplifier that provides both AC and DC negative feedback for driving the output stage at a vertical rate in a sawtooth manner to generate a sawtooth deflection current in the deflection winding and for establishing a DC operating voltage level at the output terminal that charges the DC blocking capacitor. A service mode switching circuit is coupled to the driver stage for asserting the service mode of operation by maintaining the first output amplifier in cutoff and the second output amplifier in conduction to discharge the DC blocking capacitor and disable the generation of the sawtooth deflection current.

Abstract: An electron beam magnetic deflection system capable of raster and stroke deflection and providing minimum power dissipation in raster mode. Automatic switching of the voltage demanded in raster mode is obtained by continuously sampling the yoke current, the power supply voltage being switched in magnitude and polarity corresponding to the direction of change and polarity of the yoke current. By returning energy stored in the yoke to the power supply during portions of the raster cycle, power efficiency is substantially enhanced.

Abstract: An apparatus for generating a periodic resonant pulse voltage across an inductance includes first and second switches coupled together in a series cascode arrangement. The cascode arrangement applies a first voltage to an inductance for storing energy therein. A periodic switching signal is coupled to the second switch. Each cycle of the switching signal includes a turn-on portion and a turn-off portion. The initiation of the turn-off portion makes the second switch nonconductive to enable the inductance and a resonating capacitance to form a resonant circuit that generates a resonant pulse voltage at a terminal of the resonant circuit. A damper switch is coupled to the inductance for terminating the generation of the resonant pulse voltage at the end of the first interval, prior to the initiation of the turn-on portion of the switching signal.

Abstract: A transformerless switching circuit is described for rapidly turning a horizontal output transistor off and on in response to horizontal rate input pulses. The switching circuit includes a first transistor which is rendered alternately conductive and non-conductive by the input pulses, a second transistor which supplies base drive to the horizontal output transistor in response to the first transistor being conductive, and a third transistor which turns off the horizontal output transistor rapidly in response to the first transistor being non-conductive. The conduction level of the second transistor is controlled by temperature compensating means such that base drive to the horizontal output transistor is varied to compensate for temperature induced current gain changes in the output transistor, thereby holding the latter transistor to a substantially constant saturation current.

Abstract: The signal amplifier is used for amplification of an input signal with varying control amplitude, particularly in the field of electromedicine. The amplifier contains at least two amplification paths which supply current to the deflection coil of the recording device. In the first path is arranged a first individual amplifier which is designed as a voltage-controlled current source. It is rated for a lower control range. This lower range is chosen to be the range in which the input signal lies during relatively long periods of time. In the second path is arranged a second individual amplifier. This amplifier is designed as a voltage amplifier. It is rated for a higher control range and supplies the deflection coil with peak current during relatively short periods of time.

Abstract: A circuit for generating a sawtooth current (I) in a coil (25), the coil (25) being driven during the trace periods of the sawtooth from an amplifier circuit (4, 6, 7, 9, 15) by a current, and during the shortest possible retrace periods, the amplifier circuit being blocked, the coil (25) being included in a resonant circuit (25, 20, 21, 18, 7) which further comprises a capacitor (20), a first (21) and a second diode (18) and a transistor (7). In order to prevent disturbing ringing phenomena from occurring when a retrace period of the shortest possible duration is required, the junction of the capacitor (20), the first (21) and the second diode (18) and the transistor (7) is fed-back via a resistor (23) to a signal input of an amplifier (4) comprised in the amplifier circuit (4, 6, 7, 9, 15), this signal input further being coupled to a terminal (1) for the supply of a sawtooth voltage.

Abstract: A dynamic new circuit is disclosed which permits an extremely high resolution cathode ray tube display. Utilizing this circuit, horizontal drive operating frequency may be increased by a factor of approximately four and video drive operating frequency may be increased by a factor of approximately ten. Improved circuits for horizontal drives vertical drive, video drive and associated circuitry are disclosed which cooperate to produce a high frequency display which has unparalleled clarity and resolution.

Abstract: A horizontal width control circuit for use with an image display apparatus includes first and second variable inductors connected in series and shunt relationship respectively with a horizontal deflection coil. The inductance of the inductors are variable in opposite directions for controlling the extent of horizontal deflection through a relatively large range of values without detuning the horizontal deflection circuits.

Abstract: A deflection coil driver includes a current driver stage comprising three power transistors, a first power transistor being caused to turn on via a class B transistor stage when an input signal of a first polarity is input to the class B stage, second and third power transistors being caused to turn on via said class B stage when the input signal has an opposite polarity. When turned on, the first power transistor couples current from a positive voltage source to the deflection coil, the second power transistor couples current from a negative voltage source to said coil, and the third power transistor couples said coil to ground. A transistor switch determines whether the second or the third power transistor is on, as a function of the voltage across the deflection coil. The current through the coil is also sensed and provides negative feedback to an input amplifier to ensure that the shape of such current matches the shape of the input signal.

Abstract: A cathode ray dual mode electromagnetic beam deflection amplifier system for providing current for driving a deflection coil, and means for switching between linear and resonant non-linear operational modes. In the linear mode, the deflection coil current is controlled to closely follow an applied input deflection sweep voltage and operates as a push-pull amplifier. In the non-linear resonant mode, one-half the output stage is abruptly decoupled from the deflection coil such that energy stored in the deflection coil is discharged into a series capacitor, the subsequent resonant pulse being returned through the non-decoupled half of the output stage to a power supply.

Abstract: A resonant retrace vertical deflection circuit comprises a retrace capacitor which forms a resonant circuit with the yoke vertical deflection windings during retrace of the electron beams. One or more diodes isolate the yoke from the circuit power supply to allow the yoke voltage to increase beyond the level of the supply to provide faster retrace. A second power supply is provided to precharge the retrace capacitor prior to retrace, resulting in a further decrease in retrace time.

Abstract: Disclosed is a vertical drive circuit for a cathode ray tube in a video display in which sawtooth current waveform corrections for the deflection yoke are made by means of an S-correction feedback loop featuring DC-coupling and low frequency filtering. The amplified correction signal is transmitted to a push-pull type output stage for driving the deflection yoke. Power consumption is reduced and operation made more efficient by an approximate doubling of the retrace voltage applied to the push-pull output stage during retrace by means of a discharging capacitor network.

Abstract: An improved drive for the deflection coil of a cathode ray tube. A first deflection, low-power supply means drives the deflection coil causing the electron beam to scan the face of the tube. A separate second deflection, high-power supply means drives the deflection coil causing retract of the beam. A switch means including a mono-stable multi-vibrator produces an output pulse of selected duration which controls a transistor switch connecting the second supply means to the deflection coil during the retrace cycle. A source of sync signals connected to the multi-vibrator produces the pulse input signals necessary to drive the multi-vibrator thereby controlling the timing of the transistor switch for causing retrace. The use of a separate second high power supply permits rapid retrace, improved power supply matching and minimal heat loss.

Abstract: A circuit for driving and protecting the horizontal output transistor of a resonant raster scan display is disclosed. The driving circuitry described provides a circuit for separately establishing the currents required to turn a horizontal output transistor on and off. This transistor is turned on by a forward base current determined by beta requirements and turned off by a reverse base current equal to one half of the forward collector current. Protection against several common circuit failures is also incorporated in the circuit.

Abstract: A push-pull pair of output transistors provides trace current to a vertical deflection winding. A retrace capacitor forms a resonant retrace circuit with the deflection winding to develop a resonant retrace current in the deflection winding. A damping circuit coupled to the deflection winding damps unwanted oscillations of the trace current. A diode disconnect functions to prevent the resonant retrace current from flowing in both the output stage and in the damping circuit, thereby reducing undesirable dissipation in the vertical deflection circuit.

Abstract: An amplifier includes first and second switches coupled at a junction to form a series circuit. The series circuit is serially coupled with an inductor across a source of energizing potential. A capacitor couples the junction between the switches to a load. The switches conduct alternately under the control of a duty cycle modulator. The duty cycle modulation tends to vary the amplitude of the two opposite-polarity portions of the signal appearing across the load. A clamp is coupled to the junction of the series switch circuit and the inductor. The clamp operates during a first of the two alternate switch conduction intervals to clamp the voltage across the inductor at a fixed value. Since a direct voltage cannot be established across an inductor, the voltage across the inductor during the second switch conduction interval is established by the clamp voltage and the duty cycle, and varies with duty cycle.