JP2815353B2 - Flyback transformer device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flyback transformer device used for a television receiver or the like. 2. Description of the Related Art The high-voltage output voltage regulation characteristics of a flyback transformer affect the screen of a television receiver,
If the regulation characteristics are poor, the width of the screen of the television receiver changes with the output voltage of the flyback transformer. For this reason, there has conventionally been a device in which the horizontal deflection pulse is changed according to the output voltage of the flyback transformer as shown in FIG. In FIG. 3, reference numeral 19 denotes a flyback transformer, and a secondary coil 22 of the correction transformer 20 is connected in parallel with the primary coil 1 of the flyback transformer 19. A horizontal output transistor 16 supplies a horizontal deflection pulse to the primary coil 1 of the flyback transformer 19. 2 is a secondary coil of the flyback transformer 19,
The output voltage of the secondary coil 2 is divided to form a differential amplifier 10
Has been added to The output of the differential amplifier 10 is a correction transformer
Added to 20 primary coils. The television receiver using the conventional flyback transformer as described above is
When the output voltage of the flyback transformer 19 changes and deviates from the reference voltage, the output voltage appears at the output terminal of the differential amplifier 10. Then, the current flowing in the primary coil of the correction transformer 20 changes and the inductance of the secondary coil 22 changes, so that the horizontal deflection pulse voltage generated in the primary coil 1 of the flyback transformer also changes, and the output of the flyback transformer 19 changes. Voltage regulation characteristics are improved. There is also a conventional flyback transformer device as shown in FIG. That is, 21 is a transistor, which is connected in series to the primary coil 1 of the flyback transformer 19. 10 is a differential amplifier, and a flyback transformer 19
Is divided and applied to the input terminal, and the output terminal is connected to the base of the transistor 21. In this example, when the secondary voltage of the flyback transformer 19 changes, the output voltage of the differential amplifier 10 also changes and the transistor 21
, The output voltage regulation characteristic of the flyback transformer 19 is improved. Problems to be Solved by the Invention However, when the conventional flyback transformer as described above is used, the input voltage to the flyback transformer, that is, the horizontal pulse, is controlled by an automatic frequency control circuit in order to control the output voltage of the flyback transformer. When used as a reference pulse, the voltage and waveform of the reference pulse change, and the automatic control circuit and the like become unstable. Further, when the input voltage changes, there is a problem that the width of the screen changes. In addition, since a large-current portion on the primary side is controlled, a control element having a large loss and a coil having a large coil are required, so that there is a disadvantage that the product cost is increased. Means for Solving the Problems In order to solve the above problems, a flyback transformer device according to the present invention includes a core, a first coil to which an excitation signal wound around the core is input, and a coil wound around the core. A transformer unit having a second coil and an auxiliary coil for outputting a signal corresponding to the excitation signal, and an inductance element whose impedance changes according to the output signal of the second coil. One terminal is connected to the second coil via the rectifier circuit, and the other terminal of the inductance element is connected to the auxiliary coil. According to the above configuration, the value of the impedance of the inductance element changes in accordance with the change in the output voltage of the second coil of the transformer unit, and the voltage generated in the auxiliary coil is controlled by the value of the impedance of the inductance element. The output voltage is rectified by the rectifier circuit and added to the output voltage of the second coil, so that the voltage of the second coil is kept constant. Embodiment Hereinafter, an embodiment of the flyback transformer device of the present invention will be described in detail. FIG. 1 is a wiring diagram of one embodiment of the present flyback transformer device. 1 is a primary coil of a main flyback transformer, 2 is a secondary coil, and 3 is an auxiliary coil, each of which is wound on a common core 11. Reference numeral 4 denotes a saturable reactor which is magnetically uncoupled from the core 11. Reference numeral 6 denotes a rectifier diode, and reference numeral 7 denotes a smoothing capacitor which is connected in series to the saturable reactor 4 to constitute a rectifier circuit. Reference numerals 8 and 9 denote detection resistors for detecting a high voltage, which divide the output voltage of the secondary coil 2. 10 is a differential amplifier,
One input terminal is connected to the connection end of the detection resistors 8 and 9,
The other input terminal is connected to a reference power supply. Reference numeral 5 denotes a diode, which is connected between the output terminal of the differential amplifier 10 and the saturable reactor 4. The flyback transformer of the present invention has the above configuration and is used for a horizontal deflection circuit and a high voltage generation circuit as shown in FIG. Reference numeral 16 denotes a horizontal output transistor, 12 denotes a deflection yoke, 13 denotes an S-shaped correction capacitor, 14 denotes a resonance capacitor, and 15 denotes a damper diode, which forms a horizontal deflection circuit. The operation when used in the above-described horizontal deflection circuit will be described. A horizontal drive pulse is applied to the horizontal output transistor 16, and a horizontal deflection flyback pulse is generated in the primary coil 1 of the flyback transformer. A similar flyback pulse voltage is induced in the secondary coil 2,
DC high voltage is generated. Similarly, a flyback pulse is also generated in the auxiliary coil 3. A rectifier circuit including a rectifier diode 6 and a capacitor 7 is formed at one end of the saturable reactor 4, to which a winding start end of the secondary coil 2 of the main flyback transformer is connected,
Thereby, the connection is made such that the sum of the output voltage of the auxiliary coil 3 and the output voltage of the main flyback transformer is obtained at the final output terminal. When the high-voltage output voltage increases due to a decrease in the load current, the voltage divided by the high-voltage detection resistors 8 and 9 also increases. This signal is applied to the differential amplifier 10, and an output that is compared and amplified with the reference voltage is obtained. The output of the differential amplifier 10 approaches 0 V from minus. Then, the diode 5 is turned on during the negative half cycle of the output voltage of the auxiliary coil 3, and a reverse bias voltage is applied to the saturable reactor 4. Therefore, the saturable reactor 4 is reset and enters a high inductance state (a state where the impedance before saturation is large). Next, when a voltage of a positive half cycle of the output voltage of the auxiliary coil 3 is applied to the saturable reactance 4, the saturable reactor 4 has a hysteresis characteristic, and thus changes from a high inductance state to a low inductance state (so-called low impedance after saturation). ), It takes a long time for the state where the impedance is large, and the impedance of the saturable reactor 4 is equivalently increased. Therefore, the output voltage of the rectifier circuit including the rectifier diode 6 and the capacitor 7 decreases, the output of the secondary coil 2 of the flyback transformer decreases, and the control of stabilizing the high-voltage output voltage is performed. When the high-voltage output voltage decreases, the operation opposite to the above is performed, and the control for stabilizing the high-voltage output voltage is similarly performed. The present invention provides an auxiliary coil magnetically coupled to the secondary coil of the flyback transformer as described above, and the impedance changes between the secondary coil and the auxiliary coil according to the voltage of the secondary coil. Since the inductance element is connected, the high-voltage output voltage can be stabilized without changing the horizontal deflection pulse voltage. Therefore,
There is no particular problem even if the horizontal deflection pulse is used in an automatic frequency control circuit or a blanking circuit, and the width of the horizontal deflection pulse does not need to be changed in order to stabilize a high output voltage. There is no need to change the input voltage to the coil. For this reason, it is possible to realize a screen with little amplitude fluctuation. Further, in the flyback transformer device of the present invention, control is performed only on the secondary side, so that the primary side and the secondary side can be insulated from each other, so that safety is enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of an embodiment of a flyback transformer device of the present invention, FIG. 2 is a circuit diagram of a horizontal deflection circuit using the flyback transformer device, and FIGS. FIG. 4 is a circuit diagram of a horizontal deflection circuit having a high-voltage stabilizing function using a conventional flyback transformer device. 1 primary coil (main flyback transformer) 2 secondary coil (main flyback transformer) 3 auxiliary coil 4 saturable reactor 5 diode 6 rectifier diode 7 condenser 8 , 9 …… Detector resistor 10 …… Differential amplifier, 11 …… Core

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Masafumi Ide               Matsushita, 1006 Kadoma, Kazuma, Osaka               Kiki Sangyo Co., Ltd.                (56) References JP-A-47-30222 (JP, A)                 60-77160 (JP, U)

Claims (1)

(57) [Claims] A transformer unit having a core, a first coil to which an excitation signal wound around the core is input, a second coil to output a signal corresponding to the excitation signal wound around the core, and an auxiliary coil And an inductance element whose impedance changes in response to the output signal of the second coil. One terminal of the inductance element is connected to the second coil via a rectifier circuit. Is connected to the auxiliary coil, a signal excited by the auxiliary coil is rectified by the rectifier circuit through the inductance element, and is superimposed on a signal excited by the second coil. Back transformer device.