JPH0449779A - High voltage power supply unit - Google Patents

Abstract

PURPOSE:To attain an action stop even when abnormal high voltage is generated in a correcting transformer by providing a coil for detecting abnormal high voltage/high voltage on the correcting transformer and adding required voltage including the coil for the detecting abnormal high voltage of a main transformer to a Zener diode for stopping high voltage. CONSTITUTION:The output end of a first rectifying circuit 2 to rectify voltage generated in a coil for detecting high voltage 4 of a main transformer 1 is connected to the one end of a coil for detecting high voltage 7 and the other end of the coil 7 is connected to a Zener diode for stopping high voltage 23 through a second rectifying circuit 22. Then, the both-end voltage of the coil 4 and the both-end voltage of the coil 7 affect to the both-end voltage of the diode 23 together and even when abnormal high voltage is generated in any coil for detecting high voltage, the Zener diode can be broken down.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention (Note) relates to a high-voltage power supply device for obtaining high voltage. There is a system that generates high voltage using sawtooth current for horizontal deflection, and this type of high voltage generation transformer device is generally called a flyback transformer, but it is also used to stabilize the high voltage output voltage. Some types are equipped with a stabilizing control circuit for high voltage output.

Hereinafter, an example of a high voltage power supply section for a cathode ray tube using a conventional high voltage power supply device will be explained based on FIG.
30 is a main transformer 31 for high voltage generation is a main transformer 30
32 is the same secondary coil; 33 is a switching pulse coil wound around the same magnetic core together with the primary coil 31 and the secondary coil 32; 3
4 is a high voltage detection coil wound around the same magnetic core.
35 is a correction i-run input provided for high pressure stabilization.
36 is the primary coil of the correction transformer 35 & 37 is the secondary coil of the correction transformer 35 38 is a rectifier diode,
39 is a smoothing capacitor, 40 is a high voltage output terminal, and even if the pulse voltage generated in the secondary coil 32 is rectified and a high voltage output voltage is generated at the high voltage output terminal 40, 41 and 42 are used to divide the high voltage output voltage. The voltage 17 is a voltage dividing resistor for detecting fluctuations in the high voltage output voltage, and the voltage dividing resistor 43 starts a stabilizing control operation when the fluctuation in the output voltage detected by the voltage dividing resistors 41 and 42 exceeds a predetermined value. 44 is a switching element, and one input terminal is connected to the connection point of resistor 41 and resistor 42, and the other input terminal is connected to the reference power supply.
Using SFET Part 1. The output current of the differential amplifier 43 increases or decreases depending on the potential at point C.
4 switching timing changes, correction transformer 3
The amplitude value of the pulsed current flowing through the primary coil 36 of the correction transformer 35 changes, and the voltage generated in the secondary coil of the correction transformer 35 changes, causing the voltage at point B to change, so it is necessary to perform stabilization control. 20 is a horizontally suspended quadrant sister, 16 is a deflection coil, 17 is a figure-8 correction capacitor, 18 is a resonance capacitor, and 19 is a damper diode, and these form a horizontal deflection circuit and one of the main transformers 30. Even though the secondary coil 31 is connected to this horizontal deflection circuit, the deflection coil 16 and the resonant capacitor 18 constitute a parallel resonant circuit. Then, apply a DC voltage to both ends of this parallel resonant circuit, and then short-circuit both ends. When energy is intermittently supplied from the outside by performing a switching operation such as applying a DC voltage to both ends again, a sawtooth wave current flows in this resonant circuit with a slope that matches its natural resonant frequency. A part of the current flows into the primary coil 31 of the main transformer 30.The operation will be explained next.A horizontal drive pulse supplied from a horizontal drive pulse supply unit (not shown) equipped with an oscillation IC is horizontal. The horizontally suspended quadratic sister 20 that is applied to the suspended quadratic sister 20 repeats on and off at the horizontal deflection period by this horizontal drive pulse, causing a sawtooth wave-like current to flow through this horizontal deflection circuit, and this current becomes the horizontal deflection current. Become. A part of the sawtooth current generated in this way also flows to the primary coil 31. Therefore, a flyback pulse voltage is induced in the secondary coil 32 of the main transformer 30, which is rectified by the rectifying diode 38 and becomes a direct current. High voltage is generated 4 Mana correction transformer 35-2
The voltage generated in the next coil is also rectified by the diode 45, and the resulting DC voltage charges the capacitor 46.Then, the sum of the DC voltages obtained by rectifying the output voltages of both transformers is the output voltage. Namoji I will explain the operation related to voltage stabilization. When the load resistance becomes smaller, the output current I increases and the high voltage output voltage at the high voltage output terminal 40 decreases.4 Then, the potential at point C, that is, the voltage at the differential amplifier 43 When the potential at point C decreases, which is due to a decrease in the potential at one input terminal, the output current of the differential amplifier 43 increases, and the current in the switching element 38 also increases. Then, the pulsed current flowing in the primary coil 36 of the correction transformer 35 increases, and the voltage generated in the secondary coil of the correction transformer 35 also becomes high. Therefore, when the potential at point C decreases, the DC voltage of the capacitor 46, that is, the The potential of B rises, and the main transformer 3 connected to point B
The potential of the secondary coil 32 of 0 also increases, and the high voltage output voltage of the high voltage output terminal 40 does not rise quickly.In addition, when the high voltage output voltage becomes high, the opposite operation to the above is performed and the high voltage output In this example, even if voltage stabilization control is performed, Table 4 shows that even if a safety circuit is provided to automatically stop operation if high voltage occurs in the coil of main transformer 30 for some reason, 23 is horizontal drive. This Zener diode 23 is connected to an oscillation IC (not shown) for generating pulses.
When the oscillation IC breaks down, the operation of the above-mentioned oscillation IC stops, and the operation of this power supply circuit stops.One end of the high voltage detection coil 34 of the main F lance 30 is grounded.The other end is connected to the rectifier diode 47 and the smoothing However, even if the Zener diode 23 is connected to one end of the Zener diode 23 through a rectifier circuit consisting of a capacitor 48, and the Zener diode 23 is configured to be broken down by the voltage of the high-voltage detection coil 34, the problem that the invention attempts to solve does not occur. In the above configuration, if an abnormally high voltage occurs in the high voltage detection coil of the main transformer, the Zener diode will break down and the operation will stop (if an abnormally high voltage occurs in the correction transformer) There is no way to stop the operation, and there is a possibility of falling into a dangerous situation.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a high-voltage power supply device that can stop operation even when an abnormally high voltage occurs in the correction i-lance. The present invention solves the above-mentioned problems by adding a high-voltage detection coil to the correction transformer and connecting the output end of the first rectifier circuit to rectify the voltage generated in the high-voltage detection coil of the main transformer. The high voltage detection coil is connected to one end of the high voltage detection coil of the correction transformer, and the other end of this high voltage detection coil is connected to the Zener diode via the second rectifier circuit. Both the voltage across the voltage detection coil and the voltage across the correction transformer's high voltage detection coil affect the voltage across the Zener diode, and even if an abnormally high voltage occurs in either of the high voltage detection coils, the Zener diode will be broken. Embodiment Hereinafter, an embodiment of the high voltage power supply device of the present invention will be described in detail.

In FIG. 1, 26 is the main transformer 7, .
1 is the primary coil of the main transformer 26 for high voltage generation.
2 is a secondary coil of the main transformer 26, which is composed of a plurality of subcoils, and 3 is a switching pulse coil wound around the magnetic core 13 together with the primary coil 1 and secondary coil 2. 4 is also a magnetic coil. core 13
This is a high voltage detection coil wound around the 27 is the supplementary transformer input 5 is the primary coil of the correction transformer 27; 6 is the secondary coil of the correction transformer 27; 7. b7i; is an rI pressure detection coil wound around the magnetic core 14 of the correction transformer 27; By the way, the magnetic core 13 and the magnetic core 14
is arranged so that it is magnetically non-coupled,
8 is a rectifier diode, 9 is a high voltage output terminal, and even if a plurality of rectifier diodes 8 are inserted between each subcoil of the secondary coil 2 and at the high voltage side end, the pulse voltage generated in the secondary coil 2 is rectified and the high voltage output terminal 9
410.11 is a voltage dividing resistor that divides the high voltage output voltage, and is used to detect fluctuations in the high voltage output voltage for constant voltage control. Although the configuration of the parts related to is similar to the conventional example shown in Fig. 3, 12 is a switching element using a differential 7-inch, I51.4 MO3FET, and detailed explanation of these names will be omitted. Also 2
4 is a rectifying diode that rectifies the voltage generated in the secondary coil of the correction transformer 27, and 25 is a capacitor charged by the obtained DC voltage.The low voltage side end of the secondary coil 2 of the main transformer 26 is a capacitor. 25, and the sum of the DC voltages obtained by rectifying the output voltages of both transformers appears at the output terminal 9.Next, I will not explain the safety circuit against abnormal high voltage.
One end of the high voltage detection coil 4 of the main transformer 26 is grounded, and the other end is connected to the low voltage side end of the high voltage detection coil 7 of the correction transformer 27 via the rectifier diode 2I. The high-voltage side end of 7 is connected to one end of a Zener diode 23 via a rectifier diode 22. 28 is a capacitor that smoothes the voltage rectified by the rectifier diode 21, and is connected to point e.
29 is a capacitor that smoothes the voltage rectified by the rectifying diode 22, and is connected to the point f. A voltage is generated which is the sum of the voltage at the point e mentioned above and the DC voltage according to the peak value of the pulsed voltage generated in the high voltage detection coil 7.Looking at it from a different perspective, from the high voltage detection coil 4 to the rectifier diode 21 to the high voltage detection coil 7 of the correction transformer 27, and from the high voltage detection coil 7 to the Zener diode 23 via the rectifier diode 22.
Even if the voltage across the high-voltage detection coil 4 and the voltage across the high-voltage detection coil 7 are both configured to affect the voltage across the Zener diode 23, the high-voltage output voltage of the main transformer 26 or the correction transformer 27 is When the voltage rises, the output voltage of the high voltage detection coil 4.7 of each transformer rises, and the Zener diode 2
Even if the voltage across the Zener diode 23 is configured to rise, the other end of the Zener diode 23 (upper) is connected to an oscillation IC (not shown) that generates horizontal drive pulses as in the secondary example described above. Even though the oscillation IC is configured to stop operating when the Zener diode 23 breaks down, when the oscillation IC stops operating, the horizontal drive pulse input is cut off and the main transformer 26 stops operating. L-Next, the operation of the correction transformer 27 is also stopped, and therefore it is possible to prevent an abnormal rise in the high-voltage output voltage. This is a circuit diagram illustrating an example of the case where this is used, and in this example, as in the example of FIG. Although the deflection circuit is configured and its operation will not be explained next, since the secondary coil 2 of the main transformer 26 and the secondary coil 6 of the correction transformer 27 are connected in series with each other, the respective secondary coils of both transformers The sum of the generated voltages appears at the output terminal 9, and the stabilizing circuit works to stabilize the sum of the output voltages of both transformer devices. Add a high voltage detection coil to the transformer L Connect the output end of the first rectifier circuit for rectifying the voltage generated in the high voltage detection coil of the main transformer to -'M of the high voltage detection coil of the correction transformer to detect this high voltage. The other end of the high voltage detection coil of the main transformer is connected to the Zener diode via the second V current circuit. Since the Zener diode can be broken down even if an abnormally high voltage occurs in any of the high voltage detection coils, safety can be further improved.

[Brief explanation of drawings]

Fig. 1 shows a circuit of a high-voltage power supply device according to an embodiment of the present invention. Fig. 2 shows a circuit showing an example where the high-voltage power supply device according to the same embodiment is used in a high-voltage power supply section of a television receiver.
Figure 3 is a circuit diagram of a conventional high-voltage power supply device. 1: Primary coil 2: Secondary coil 3: Switching pulse coil 4: High-voltage detection coil 5: Primary coil 6: 2
Secondary coil 7: High voltage detection coil 8: Rectifier diode 9: High voltage output terminal 10.11:
Voltage dividing resistor 12: Differential amplifier 15: Switching elements 24, 21, 22: Rectifier diode 27:
Correction transformer 26: Main transformer 25, 2
8, 29: Name of capacitor agent: Patent attorney Shigetaka Awano Haka I base cylinder diagram

Claims (1)

[Claims] A primary coil connected to a pulsed current source, a secondary coil for generating high voltage, a switching pulse wave generation coil for generating a switching pulse wave for stabilization control, and a main transformer equipped with a high voltage detection coil; a high voltage rectifier for rectifying the voltage generated in the secondary coil of the main transformer; and a first rectifier circuit for rectifying the voltage generated in the high voltage detection coil of the main transformer. and an auxiliary transformer including a primary coil and a secondary coil, and a control transformer whose on time changes according to fluctuations in the output voltage of the high voltage rectifier from the pulsed voltage generated in the switching pulse wave generating coil. One of the auxiliary transformers has a control circuit that generates an alternating current signal, and a switching element that breaks down and stops the operation of the pulsed current source when the voltage at both ends exceeds a predetermined level. Connect the above control circuit to the next coil, and
The output voltage is the sum of the correction voltage obtained by rectifying the voltage of the next coil and the high-voltage DC voltage generated by the high-voltage rectifying means, and high-voltage detection is performed to detect abnormal high voltage in the auxiliary transformer. A second rectifier circuit is installed at one end of the high voltage detection coil, and a second rectifier circuit is installed at one end of the high voltage detection coil of the auxiliary transformer, and a second rectifier circuit is installed at one end of the high voltage detection coil of the auxiliary transformer.
A high-voltage power supply device connected to an output end of a rectifier circuit so that the voltage at the output end of the second rectifier circuit is applied to the Zener diode.