KR840000342B1 - Switching regulator for a television apparatus - Google Patents

Abstract

A controllable switch is coupled to a source of unregulated direct voltage and in a closed loop with a filter inductor and a storage capacitor. Its on-off state is controlled at the horizontal deflection rate to control the voltage across the capacitor and regulate a voltage. A diode is coupled with the filter inductor and storage capacitor to form a second series circuit through which current can continue to flow in the inductor when the controllable switch is opened.

Description

Switching regulator for TV devices

1 to 4 are partial block schematic diagrams of a television display embodying the present invention.

5 and 6 are amplitudes and time waveform diagrams of voltages and currents periodically occurring during operation of the apparatus.

7 is a partial block schematic diagram of another embodiment apparatus of the present invention.

FIG. 8 shows a device similar to the device of FIG.

FIG. 9 is a voltage versus time waveform diagram of the retrace pulse seen during operation of the apparatus of FIG. 8. FIG.

The present invention relates to a voltage regulator for a television display having excellent features.

In order to avoid the problems of weight and cost of the line separating transformer, a television receiver is directly supplied with power through a rectifier and a filter from an AC line. In this case, the filtered DC voltage may change in proportion to the change of the AC line voltage, which is not preferable. In addition, the value of the filtered DC voltage may be approximately the peak value of the AC current input, and may be larger or smaller than the required value.

The use of a series pass voltage regulation circuit can produce a regulated output voltage with a value less than an unregulated direct current input, but this is accompanied by a significant power consumption when the difference between the unregulated voltage and the regulated voltage and the load current are large. There is a flaw.

In recent years, power saving has been emphasized, and the use of switching adjustments for power supply to television receivers is increasing. In the switching regulator, a switch coupled to an unregulated DC voltage source is periodically interrupted with an impact factor suitable for the adjustment of the controlled voltage. U.S. Patent No. 4,024,434 describes the use of transistors that operate as switches with low power consumption. Although the power consumption is reduced by this type of operation, many transistors have low gains and require a significant base drive current to saturate at low power. In addition, inductors often associated with switching regulators require so-called free-wheeling diodes to prevent the application of excessive voltages at the time of blocking the transistor and also to sacrifice the energy accumulated in the inductor.

The use of a control rectifier such as SCR can avoid the problem of base driving associated with the use of a transistor switch. The SCR remains in the conduction state once the conduction circuit is conducting as long as it is forward biased. Therefore, in order to conduct the SCR, a gate pulse may be instantaneously applied to the control electrode of the SCR, and it is not necessary to continuously supply any current to maintain the conduction state. The control regulator is normally shut off when the forward current drops to zero and tries to reverse by applying a reverse voltage from an external power source. Compared with transistors, SCRs have good control characteristics and are advantageous because they are not destroyed even when a reverse voltage above the inverse voltage is applied to the transistor.

U.S. Patent No. 3,970,780 describes a switching regulator using SCR as a control element for controllably charging a capacitor from an unregulated power supply through a series circuit consisting of a winding and a inductor in a horizontal deflection circuit. In such a configuration, the inductor must be small enough so that the current flowing through the SCR falls to zero by the difference between the blocking voltage pulse and the unregulated DC voltage between the windings during the return period. As a result, a relatively large peak current flows between the inductor and the capacitor between the chargers of the capacitor, and there is an irrationality that I ² R, that is, the heat loss is relatively large due to such a relatively large current. In addition, a large change in the peak current of the regulator occurs due to a relatively large change in the adjustment current due to a change in the load current, such as due to a change in the beam current of the image tube, for example, a beam tube. A large change in peak current flowing through the SCR of the regulator and the blocking winding results in a quantitative change in the energy between the winding and the horizontal output transistor of the deflection circuit, which is a function of beam time modulation and charge time modulation at the output transistor base as a function of beam current. Cause. The charge time modulation causes the vertical lines to appear in the raster. It is desirable to reduce the curvature caused by return time modulation and beam current change, to reduce peak current and heat loss, and to reduce the load dependent variation of the voltage pulses for the shutoff regulator so that larger filter inductors can be used.

In a switching regulator for a television apparatus according to a preferred embodiment of the present invention, a first series circuit composed of a controllable switch, an inductor and a horizontal deflection generator is coupled in parallel to an unregulated direct current voltage source, so that the inductor is closed for a period of time when the switch is closed. It becomes the passage of the increasing current flowing through. The switch has a gate and a leading circuit, which remain open, or non-conducting, until a signal is applied to the gate during forward bias, and closed or conducting as long as forward bias is maintained after the gate signal is applied. Keep it. When the horizontal frequency signal from the deflection generator is applied to the main circuit by the coupling device, the switch is controlled and opened. The diode coupled to the inductor forms a path of reduced current flowing through the inductor for at least a portion of the period in which the switch is open. A capacitor is coupled to the deflection generator so as to filter the current flowing through the inductor to form an operating voltage for the deflection generator. A control circuit is coupled to the deflection generator and the gate for closing the switch to control the driving voltage in a feedback manner by controlling the average of the increase current and the decrease current of the inductor.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, terminals 10 and 12 are adapted to be coupled to a source of unregulated direct current voltage, such as rectified filtered power line voltage. The anode-cathode converter and filter inductor 16 and horizontal deflection circuit 22 of the SCR 14 are combined as shown at circuit points 26 and 30 to form a first series circuit.

This series circuit is provided between the terminals 10 and 12 via the secondary winding 20b of the transformer 20. The capacitor 18 is coupled between the terminal 12 and the circuit point 30, and the deflection circuit 22 is driven by the voltage generated between the both ends of the capacitor. Diode 24 has a positive electrode coupled to terminal 12 (hereinafter referred to as ground point) and a negative electrode coupled to inductor 16 through circuit point 26, inductor 16, capacitor 18, diode 24 A second series closed circuit of current flowing through

The voltage control circuit, shown at block 36, is grounded and coupled to circuit point 30 through lead 28. The voltage control circuit 36 may use the form of US Pat. No. 3,970,780, for example. The voltage control circuit 36 senses the voltage between the circuit point 30 and the ground point, and generates a periodic gate pulse. This pulse is applied through the transformer 32 to the gate of the SCR 14, keeping the voltage at the circuit point 30 substantially constant with respect to the ground point. The horizontal deflection circuit 22 and the voltage control circuit 36 are coupled by conducting wires 34, so that the periodic gate pulse and the horizontal deflection are synchronized as is known. The primary winding 20a of the transformer 20 is coupled to the horizontal deflection circuit 22, so that the return voltage pulse from the horizontal deflection circuit is passed between the anode and the cathode of the SCR 14 through the secondary winding 20b. The SCR 14 is periodically turned off by supplying it to a current furnace.

In operation, the voltage control circuit 36 generates the SCR gate pulse shown by V ₃₆ in FIG. 5A. The pulse is generated with the timing related to the retrace voltage pulse, such as a first-degree V 5b _20a generated in the primary winding (20a) by a horizontal deflection circuit (22). At this time, as shown in FIG. 5, just before the time point T ₀ , the voltage generated by the winding 20b is small and the SCR 14 is in a conductive state, so that the circuit point 26 and the terminal 12 The voltage is positive as shown in FIG. 5C and the diode 24 is reverse biased. In this manner, when the SCR 14 is in a conductive state, an unregulated voltage is applied between both ends of the series circuit including the winding 20b, the inductor 16, and the horizontal deflection circuit 22, and I ₁₆ and 5E of FIG. _An increasing current is generated in inductor 16 and winding 20b as shown by 20b. This current charges the capacitor 18 and supplies the necessary current to the horizontal deflection circuit 22. The voltage at the circuit point 30 is slightly increased by the charging of the capacitor 18.

At the time point T ₀ , the deflection circuit 22 starts to output the retrace pulse. As the retrace voltage rises, the anode voltage of the SCR 14 gradually becomes negative. Flows in the SCR (14) to the time point T ₁ by the energy associated with the magnetic field to continue the current, the anode of the SCR (14) at a time point T ₁ substantially is at the ground potential circuit point 26 of the inductor 16 is the SCR It is negative with respect to the ground point due to the decrease in the forward conductivity. At this point, the diode 24 takes over the conduction state from the SCR 14, and the SCR 14 is reverse biased by the increase of the return voltage pulse to become the non-conduction state.

After the time point T ₁ , the SCR 14 is in a non-conducting state, and part of the energy associated with the magnetic field of the inductor 16 is inductor 16, capacitor 18 and diode 24 as shown by I 24 in FIG. 5F. It is transmitted to the capacitor 16 by the reduced circulating current flowing through the second series converter. At a later time point T ₂ , the retrace period is over and the SCR 14 is forward biased again, but does not conduct until gate pulses are applied to the gate at time point T ₃ . At time T ₃ , when SCR 14 is conducting, the voltage at circuit point 26 rises until it is substantially equal to the sum of the unregulated direct current voltage and the voltage between both ends of winding 20b. Since the diode 24 is reverse biased, it is in a non-conducting state, and the inductor current I ₁₆ begins to increase again, and to the capacitor 18 and the deflection circuit 22 as energy is accumulated in the inductor 16 again. The transfer of charge continues.

As described above, the current of the inductor 16 decreases from the vicinity of the start point of the retrace period to the time point T ₃ at which the SCR 14 conducts, and stops the decrease at time point T ₃ and inverts to the increasing state. The current is filtered by a capacitor 18 to form a driving voltage of the bias circuit 22, the driving voltage is controlled by controlling the time T _3. In this way, the adjustment voltage with respect to the ground point in the circuit point 30 is larger than the required value. If there is a tendency to be lowered, as shown at time point T ₃ ′ in FIG. 5, the control circuit 36 generates gate pulses V 36 early during the deflection cycle. 5c to 5d, the average of the current I ₁₆ flowing through the winding 16 is increased purely by early gate operation, and the adjusted voltage of the circuit point 30 is increased by this pure increase. Is maintained even if the current suction increases by the deflection circuit 22, and the tendency of the adjustment voltage to decrease due to the decrease in the unregulated voltage value or other causes can be compensated.

As described above, the operation in the configuration of FIG. 1 is applied when the inductor 16 is relatively large. When the inductance value of the inductor 16 is small, the current of the winding decreases to zero before the time T ₃ at which the SCR conducts. In this case, when the current of the inductor 16 and the diode 24 stops, the circuit point ( The voltage V26 of 26 rises until it is equal to the adjustment voltage.

The above description is for the capacitor 18 as coupled between the ground point of the regulated voltage terminal 30, but the capacitor 18 may be mounted between the circuit point 30 and a reference voltage point other than the ground point. FIG. 2 is similar to the configuration of FIG. 1, but shows that the reference point of the capacitor 18 is installed differently, and the series connection of the winding 20b and the SCR 14 is replaced. In FIG. 2, the citation number which added 200 to the citation number of FIG. 1 is used for the element corresponded to the element of FIG. In FIG. 2, terminals 210 and 212 are coupled to an unregulated DC voltage source. The lead circuit of the controllable switch of the type SCR 214 and the filter inductor 216 and the horizontal deflection circuit 222 are coupled in series at the circuit points 226 and 230, which are unregulated power supply terminals. It is bound to the liver. A capacitor 216 is provided between the circuit point 230 and the terminal 210. The anode of the diode 224 is coupled to the power supply terminal 212 and the cathode is coupled to the inductor 216 at the circuit point 226 to form a series circuit with the inductor 216 capacitor 218 to form a terminal 210, A current flows in the closed circuit, including 212 and the unregulated voltage source. Between the terminal 212 and the circuit point 230 is coupled a voltage control circuit 236 for sensing the voltage across the horizontal deflection circuit 222, which is also coupled to the gate of the SCR 214 through the transformer 232. The switching of the SCR is controlled to keep the voltage between both ends of the deflection circuit substantially constant. The voltage control circuit 236 is also coupled to the deflection circuit 222 by conducting wires 234 so that the switching of the SCR 214 is synchronized with the deflection cycle. The secondary winding 220b of the transformer 220 is coupled between the circuit point 226 and the cathode of the SCR 214, and the primary winding 220a of the transformer 220 is coupled to the horizontal deflection circuit 222. . The transformer 220 applies the retrace pulse generated by the horizontal deflection circuit 222 to the SCR 214 to periodically block the SCR. For convenience of explanation, the terminal 212 is hereinafter referred to as "ground point".

The operation of FIG. 2 configuration is such that the current of the load represented by the horizontal deflection circuit 222 causes the current flow in the capacitor 218 to cause the capacitor 218 to charge, i.e., to raise the voltage between the capacitor anodes. It differs from the operation of the first configuration in that it is. Since the change in the unregulated DC voltage is considerably slower than the deflection frequency, the voltage between the terminal 210 and the ground point in each line is constant. Thus, when capacitor 218 is charged, the voltage at circuit point 230 drops to ground. In this way, as in the case of FIG. 1, the load current causes the load voltage to drop.

In the configuration of FIG. 2, the capacitor 218 must be discharged in order to raise the voltage between the both ends of the horizontal deflection circuit, which is conducted by the SCR 214 and from the capacitor 218 to the SCR 214 winding 220b inductor ( 216), when a first series circuit is formed which returns to the capacitor. During the conduction of the SCR 214, current is also supplied to the deflection circuit 222 via the SCR 214 and the inductor 216. When the SCR 214 is interrupted by the retrace pulse applied by the winding 220b, the magnetic field accumulated energy of the inductor 216 is used to continue the current supply to the deflection circuit 222, and also the inductor 216 Is used to discharge the capacitor 218 through the second series circuit, which is returned to the inductor 216 via the circuit point 230, capacitor 218 unregulated voltage source facing diode 224. When this is done, part of the accumulated energy returns to the unregulated voltage source.

The operation of the configuration of FIG. 2 will be described with reference to FIG. Just before the time T ₀ at which the deflection circuit 222 generates a return voltage pulse, the SCR 214 is in a conducting state, and the voltage at the circuit point 226 is equal to the unregulated voltage as shown by V226 in FIG. 5C. It is substantially equal to the sum of the voltages between both ends of the winding 220b. The current of the inductor 216 is increased as shown by I 216 of FIG. 5d under the voltage action across the capacitor 218, and at the same time, the current of the inductor 216 is also wound as shown in FIG. 5e. Flows). At time T ₀ , a retrace pulse V220a is applied to the primary winding of transformer 220, and a pulse voltage is applied between circuit point 226 and the cathode of SCR 214 and the circuit point 226 is negative. ) Cathode becomes positive. As long as the SCR 214 is conducting, its cathode is substantially at an unregulated direct current voltage, so that the circuit point 226 is gradually driven negatively with the rise of the return voltage. At the time point T ₁ , the voltage pulse between both ends of the winding 220b is substantially equal to the unregulated DC voltage, and the circuit point 226 is negative by 1 Vbe with respect to the ground point so that the diode 224 conducts.

Further, even when the pulse voltage between both ends of the winding 220b rises, the circuit point 226 is no longer negative, the cathode of 214 becomes more positive than the terminal 210, and the SCR 214 is non-conducting. If SCR 214 becomes non-conductive at time T ₁ , current is returned to SCR 214 through inductor 216, circuit point 230, and capacitor 218 instead of terminal 210 of the unregulated voltage source. From 212 through diode 224 back to inductor 216. A portion of the current flowing through inductor 216 flows through circuit point 230 to deflection circuit 222 and back through diode 224. In this way, a portion of the energy accumulated in the magnetic field associated with the inductor 216 is returned to the unregulated voltage source and the other portion is supplied to the deflection circuit 222. At time T ₂ , the retrace period is over and the SCR 214 is forward biased again, but thereafter the non-conducting state until time T ₃ when gate pulse V236 is generated by voltage control circuit 236 as shown in FIG. 5A. Is maintained. At time T ₃ , SCR214 begins to conduct and the voltage at circuit point 226 rises, causing diode 224 to become nonconductive again. The inductor 216 is coupled in parallel to the capacitor 218 by the SCR 214 and the capacitor 218 starts discharging and the energy accumulated as the voltage between the anodes is through a series circuit including the SCR 214. Sent to inductor 216. As a result, the current of the SCR 216 gradually increases as shown in FIG. 5D.

The voltage at the circuit point 230 of FIG. 2 is adjusted by controlling the average current of the inductor 216 formed up to the time point T ₃ at which the SCR 214 conducts during the deflection cycle.

Thus, if the adjustment voltage with respect to the ground point of the terminal 230 tends to fall below a required value, the gate pulse V236 is generated at an early point in the deflection sprout as shown at the point T ₃ in FIG. . As shown by the dashed lines in FIGS. 5C-5E, the early gate action results in a net increase in the average of the current I 216 flowing through the inductor 216, whereby the capacitor 218 is larger than before. Even if the current is increased by the deflection circuit 222 due to the discharge, the adjustment voltage can be maintained, that is, the compensation voltage can be compensated. As in the case of FIG. 1, the above description is for the case where the inductor 216 has a relatively large inductance, and when the inductance is small, the current of the inductor 216 is reduced to zero before T ₃ , and the diode 224 Is non-conducting, and the circuit point 226 becomes the adjustment voltage.

In the embodiment of Figs. 1 and 2, the secondary winding is coupled in series to the SCR, but this secondary winding may be coupled in series to the diode as shown in FIG. In FIG. 3, elements corresponding to those of FIG. 1 are denoted by the quotation numbers of 300 plus the quotation numbers of FIG. In FIG. 3, terminals 310 and 312 are for coupling to an unregulated direct current voltage source, and an SCR 314 acting as a controllable switch is coupled with a filter inductor 316 at circuit point 326. 316 is coupled to deflection circuit 322 at circuit point 330, and this series coupling is coupled between terminals 310 and 312 to establish a first series passage for current flow in inductor 316. Form. A capacitor 318 is coupled between the circuit point 330 and the terminal 312 to filter the current flowing through the inductor 316 to form the driving voltage of the deflection circuit 332. Diode 324 has a cathode coupled to circuit point 326 and an anode coupled to terminal 312 (ground point) via secondary winding 320b of transformer 320, inductor 316, capacitor 318. A closed current circuit is formed to return to the inductor 316 through the winding 320b and the diode 324. Primary winding 320a of transformer 320 is coupled to horizontal deflection circuit 322. Between both ends of the capacitor 318 a voltage control circuit 336 for sensing the regulated voltage is coupled by the conductor 328, which is also connected to the horizontal deflection circuit 322 by the conductor 334. It is coupled to and can accept sync pulses. The voltage control circuit 336 generates a time modulated SCR gate pulse, which is applied to the gate of the SCR 314 through the transformer 332.

In the waveform of FIG. 6, just before the start time T ₀ of the retrace period, the SCR 314 is turned on so that the circuit point 326 becomes the voltage of the unregulated voltage source as shown in FIG. 6C. The diode 324 is also non-conductive, the anode of which is negative relative to the ground point by the voltage across both ends of the winding 320b, as shown by V301 in FIG. 6B. The current flowing through the inductor 316 is the SCR 314 and the inductor 316 from the unregulated voltage terminal 310 due to the voltage difference between the circuit points 326 and 330 as shown in Figure 6d I 316. Increase in converter through. This portion of the current is applied to the horizontal deflection circuit 322, the rest of which charges the capacitor 318.

At time T ₀ , deflection circuit 322 generates a return voltage pulse, which is applied to secondary winding 320b of transformer 320. This voltage has a polarity that sets the circuit point 301 to the ground point. At time T ₁ , diode 324 is in a non-conducting state until the voltage at circuit point 301 is ₁ Vbe higher than the voltage at circuit point 326.

At time point T ₁ , diode 324 and winding 320b form another path to the current flowing through inductor 316. After the time point T ₁ , the voltages of the two circuit points 301 and 326 are further increased by the retrace voltage pulses, so that the SCR 314 becomes non-conductive, and at a further point in time, The return voltage pulse begins to decline after reaching peak. After the pulse 301 drops below the regulated B + voltage, the energy associated with the magnetic field of the inductor 316 continues to be transferred to the capacitor 318, which includes the capacitor 318, the winding 320b, and the diode 324. The reduction current continues to flow through the inductor 316 in the closed circuit. At the time T ₂ , the SCR 314 is forward virus again by the falling voltages of the circuit points 301 and 326, but is not conducted until the application of the gate pulse.

At the time point T ₃ , the retrace pulse ends and the circulation of current continues through the inductor 316, the capacitor 318 and the diode 324 as shown by I316 in FIG. 6D. At time T ₄ , the SCR 314 is driven to drive by the voltage control circuit so that the voltage at the circuit point 326 rises, and the diode 324 becomes non-conductive to increase the current flowing through the inductor 316. It begins. As in the case of FIGS. 1 and 2, the adjustment voltage between the circuit point 330 and the ground point is maintained by controlling the average value of the current I316 determined at the relative gate time T ₄ at which the SCR 314 is conducted.

4 shows an embodiment of the invention as shown in FIG. 3 in which the secondary winding and the diode are series coupled. The configuration of FIG. 4 differs from that of FIG. 3 in that the capacitor has a different reference point and is coupled to the negative terminal of this unregulated voltage source.

In FIG. 4, terminals 410 and 412 are coupled to an unregulated direct current voltage source. The cathode of SCR 414 is coupled to terminal 412, which is coupled to terminal 410 via circuit point 426, filter inductor 416, ground point, and horizontal deflection circuit 422. Here, the ground point corresponds to the circuit point 30 of FIG. A capacitor 418 is coupled between the input terminal 412 and the ground point to filter the voltage between both ends of the biasing circuit 422. The anode of diode 424 is coupled to circuit point 426 and the cathode is coupled to positive terminal 410 of the unregulated voltage source via secondary winding 420b of transformer 420. The retrace pulse generated by the horizontal deflection circuit 422 is applied to the winding 420b. The voltage control circuit 436 coupled to the horizontal deflection circuit by the conducting wire 428 detects the horizontal deflection circuit driving voltage appearing between the terminal 410 and the ground point to generate a control pulse, which is generated by the SCR 414 through the transformer 432. ) Is applied to the gate.

The voltage across the horizontal deflection circuit 422 is equal to the difference between the voltage across the capacitor 418 and the unregulated power supply voltage. In accordance with the operation of the deflection circuit 422, the capacitor 418 is charged during the non-conduction period of the SCR 414 by the current flowing through this circuit, and electric charges are accumulated therein. Such charging raises the voltage between the both ends of the capacitor and reduces the voltage applied to the deflection circuit 422. By the series circuit returning from the capacitor 418 to the capacitor 418 via the inductor 416, the circuit point 426, and the SCR 414, and when the SCR is not conducting, the circuit point from the capacitor 418 426. The regulated voltage is controlled by discharging the capacitor 418 by control of the capacitor 418 by the diode 424, the winding 420b, the terminal 410, the power supply, and other currents that return to the capacitor 418 through the terminal 412. Controlled.

The waveform of FIG. 6 is similar in appearance to the waveform appearing during the operation of the configuration of FIG. 4, but the polarity is changed by the difference of the voltage reference point, and the magnitude is sometimes different by a certain voltage. Just before the start of the return period T ₀ , the SCR 414 is in a conductive state and the diode 424 is in a non-conductive state. The current flowing through the inductor 416 increases under the impulse of the voltage across the capacitor by energy transfer from the capacitor 418 to the inductor 416. During the retrace period, the winding 420b generates a pulse voltage that negatively increases with respect to the terminal 410 to the cathode of the diode 424. When the cathode of diode 424 becomes negative by about 1 Vbe with respect to circuit point 426 due to this pulsed voltage, SCR 414 begins to become non-conductive and diode 424 begins to conduct, leading to diode 424, Winding 420b causes the current flowing through the unregulated voltage source capacitor 418 and other series circuits of inductor 416 to be reduced.

At the end of the retrace period, the voltage between both ends of the winding 420b is small, and current continues to flow through the other direct path and the diode 424.

As a result, the voltage at the circuit point 426 approximates the voltage at the terminal 410 and the SCR 414 is forward biased. During the period from the end of the retrace period to the point at which the SCR 414 conducts, the current in the inductor 416 decreases because the inductor 416 is substantially coupled to an unregulated voltage source and energy is transferred to the voltage source. . The current reduction of the inductor 416 ends at a point corresponding to the time point T _{6 of} FIG. ₆ , at which time the SCR 414 is turned on so that the voltage at the circuit point 426 is negative and the diode 424 is cut off. The voltage of the capacitor 418 is again applied to the inductor 416 to begin the increase of current and energy that is triggered by the inductor 416.

Adjustment of the voltage between the both ends of the horizontal deflection circuit 422 of FIG. 4 configuration is performed by controlling the average value of the periodically increasing and decreasing current flowing through the inductor 416 as in the other embodiment, and the control is performed by the variable gate. It is controlled by the time point T ₄ .

7 shows an adjusting portion, a deflection portion and an alternating portion of a television receiver embodying the present invention.

In FIG. 7, the unregulated B + power supply terminal 10 is coupled to a pulsed DC current source such as a rectifier coupled to an AC power line portion. Between the terminal 10 and the ground point is coupled a filter capacitor 13 which filters the pulsating direct current and generates the original drive voltage for the other part of the receiver. In the controllable switch of the SCR 14 type, the positive electrode is coupled to the terminal 10 and the negative electrode is coupled to one end of the winding 16b of the transformer 16 '. The other end of this winding 16b is coupled to one end of the filter inductor 17 and the other end of the inductor 17 is grounded through the filter capacitor 18. The connection point Br between the inductor 17 and the capacitor 18 is connected to one end of the winding 16a of the transformer 16 '. The winding 16a acts as an input inductor with respect to the horizontal deflection circuit 22. The deflection circuit 22 includes an NPN transistor 23 whose collector is coupled to the end of the winding 16a opposite the junction Br and whose emitter is grounded. The damper diode 25 is coupled in parallel to the collector emitter path of the transistor 23. A deflection winding 29 associated with the image tube 31 is coupled in series to the S-shaped capacitor 33, which series coupling is coupled in parallel to the diode 25. The retrace capacitor 35 is coupled in parallel with the diode 25 to supplement the capacity of the winding 29 to set the proper duration of the retrace period. The winding 16c of the transformer 16 'is grounded at one end thereof, and the other end thereof is coupled to the alternating electrode of the image tube 31 through a rectifier shown by a diode 37 to perform peak rectification of the retrace pulse to direct current of the image tube. It is supposed to generate alternating voltage. The drive signal of the horizontal deflection frequency generated in the horizontal oscillator shown by block 38 is applied to the base of the transistor 23. The horizontal oscillator 30 also generates a synchronous pulse of horizontal frequency and applies it to the voltage control circuit shown by 40. The control circuit 40 coupled to the connection point Br is also coupled to the gate of the SCR 14 to control the SCR in a known manner so that the voltage at the connection point Br is kept at a constant value. A diode 342 is coupled between the connection point and ground point of the winding 16b and the inductor 17.

In the normal operation, at some point in the horizontal scanning period, the SCR 14 is turned on by the control of the voltage control circuit 40, and during the period of conduction, unregulation between the adjustment voltage VBr of the connection point Br and the both ends of the capacitor 13 is performed. The current of the inductor 17 increases at a ratio determined by adding the voltage between both ends of the winding 16D to the voltage difference between the voltages B +. At the end of the horizontal scanning period, a retrace voltage pulse is generated between both ends of the capacitor 35, which is applied from the winding 16a to the winding 16b. The voltage between both ends of this winding 16b becomes the same polarity as reverse biasing the SCR 14 to reduce the current of the inductor 17. Since the current of the inductor 17 flows through the diode 342 and the capacitor 18 during the retrace period, the inductor 17 may be able to have any value as necessary. When the current in winding 16b is zero, SCR 14 is non-conducting in preparation for the next cycle's adjustment operation. In the configuration of FIG. 7, the adjustment of the voltage VBr is performed by conduction shock coefficient modulation of the SCR 14, and this impact coefficient modulation is performed by changing the time point at which the SCR 14 is conducted during the horizontal deflection period.

If it is necessary to compensate the retrace pulse amplitude as a function of the image beam beam current, the embodiment shown in FIG. 8 may be used.

In FIG. 8, the same reference number is used for the element corresponding to the element of FIG. 8, the winding 416 of the transformer 16 'is shown, which is separated into two portions 416a, 416b by tabs. A diode 442 is provided between the tab of the winding 416 and the ground point. In the operation of the configuration of FIG. 8, at some point during the horizontal scanning period, the SCR 14 is conducted by the control of the voltage control circuit 40, which is adjusted between both ends of the capacitor 18 and the deflection circuit 22. FIG. It is controlled to keep the voltage VBr substantially constant. By controlling the conduction time of the SCR 14, the period during which the voltage is applied to the inductor 17 changes, and the current at the time of the retrace period changes as described above. Due to the change in the beam current of the image tube, an increase corresponding to the current change in the charging of the capacitor 18 and the current flowing through the inductor 17 at the time of the retrace period appears. During the retrace period, a retrace pulse appearing between both ends of the capacitor 35 is applied to the winding 416 through the winding 16a. The pulse portion occurring between both ends of the winding 416a puts the SCR 14 into a non-conductive state when the pulse amplitude is equal to the unregulated DC voltage. In this way, the high reliability SCR blocking effect is obtained in the configuration of FIG. 3 regardless of the value of the inductor 17. FIG.

During the retrace period, the diode 442 conducts, and the current flowing through the inductor 17 drops to zero due to the sum of the retrace period pulse appearing between both ends of the winding 416b and the adjustment voltage VBr. At the same time, the inductor 17 is coupled to the winding 416b by a diode 442 and a capacitor 18, and the inductance of the inductor 17 is the fly back winding 16a and the deflection winding 29 as in the case of FIG. ) In parallel. The time that the current flows through the inductor 17 and the time that the diode is in a conductive state during the retrace period depend on the magnitude of the current flowing through the inductor 17 at the time of the retrace period. Thus, the diode 442 continues to conduct for a larger portion of the retrace period by an increase in the image tube beam current that causes the large current flowing in the inductor 17 at the end of the retrace period. For this reason, the inductor 17 remains in parallel with the windings 16a and 29 for a larger portion of the retrace period, reducing the average inductance in parallel with the capacitor 35, thereby reducing the retrace period. As shown in FIG. 9, when the retrace period is shortened so that the retrace waveform 200 changes to the waveform 210, the peak retrace voltage becomes high. In this way, the configuration of FIG. 8 causes the peak retrace voltage to rise in response to the increase in the beam current, and performs adjustment compensation as well as high reliability SCR blocking of the configuration of FIG.

Other embodiments of the invention will be apparent to those skilled in the art. For example, instead of grounding capacitor 16 for propagation of a regulated voltage, it may be coupled to terminal 10. The windings 416a, 416b may be two separate windings rather than the single-tap winding of the transformer 16 '. The capacity of the windings 16a, 29 is not sufficient for the winding capacitor 35. It can also be adjusted to be removed. In addition, the timing signal of the voltage control circuit may be extracted from the difference, for example, from the transformer 16 'instead of the horizontal oscillator.

Claims (1)

A gate and a main current conductive path are provided to maintain an open state until a signal is applied to the gate while being forward biased, and remain closed and closed as long as the forward bias is maintained even after the signal is applied. A television comprising a controllable switch and a first series circuit formed of an inductor and a horizontal deflection generator, coupled between both ends of an unregulated direct current voltage source, the first series circuit being a current path for increasing current flowing through the inductor during the closed state of the switch. In the switching regulator for the device, a coupling device for coupling the horizontal frequency signal from the deflection generator 22 to the main current conductive path of the controllable switch 14 so that the opening of the main current conductive path can be controlled. (20, 220, 320, 420, 16) and the inductor (16, 17, 416b), the controllable A diode (24, 224, 324, 424, 25) coupled with the deflection generator (22) to form a current path of reduced current flowing through the inductor during at least a portion of the open state period of position A capacitor 18, 218, 318, 418 coupled to the deflection generator to filter the current to form an operating voltage for the deflection generator, and control the closing of the controllable switch 14 to control the inductor. And a control device (36, 40) which controls the average of the increasing current and the decreasing current flowing through it, so that the operating voltage can be controlled in a feedback manner.

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