DE2739037A1 - POWER SUPPLY SOURCE COMBINED WITH LINE DEFLECTION CIRCUIT FOR TELEVISION RECEIVER - Google Patents

Description

2 7 3 S O 3 7

Tandbergs Radiofabrikk A / S,

Kjelsäsveien 161, OSLO 8, Norway

Inventor: Tor Henry Moen,

Curves 28, Kjelsäs, OSLO 4, Norway

Supply voltage source combined with line deflection circuit for

Television receiver

The invention relates to a supply voltage source combined with a line deflection circuit for television receivers that a DC voltage converter with a transformer and a semiconductor controlled by the line deflection oscillator, a control circuit for setting the operating period, a control semiconductor and a drive transistor for the line deflection coil include.

In known combinations of this type, the control loop is between the line deflection oscillator and the switching device provided and regulates this within certain limits

809810/0844

ORIGINAL INSPECTED

Ratio of the control semiconductor between conductive and blocked state.

The invention is primarily intended to provide a further control range for the ratio of the control semiconductor between conductive and blocked state, regardless of the conductive and blocked state of the switching semiconductor in a simple manner to enable.

This is achieved according to the invention in such a way that the Control loop is fed by an additional secondary winding on the transformer and the ratio of the control semiconductor between conductive and blocked state regardless of the ratio of the switching semiconductor between conductive and blocked state.

The control loop can advantageously have a voltage and current switch back.

To reduce the energy consumption, according to the invention, a series connection can be made across the supply voltage input a resistor and a capacitor can be provided, a series circuit of one of resistors can be provided above the capacitor existing voltage divider can be provided, the tap of the voltage divider can be connected to the base of the switching semiconductor and stabilized supply voltage can be via a diode the connection point between resistor and capacitor in the first mentioned Series connection are supplied.

To further save on energy consumption can

according to the invention in the base-emitter circuit of the switching semiconductor a Blocking circuit be inserted, which derives supply voltage in this way and supplies the line deflection oscillator with the fact that it only works at desired times, i.e. not continuously as usual.

Two exemplary embodiments of the invention and an already known combination are explained in more detail below with reference to the drawing explained.

Fig. 1 shows a simplified circuit diagram for a known combination.

2 shows a simplified circuit diagram for a first embodiment of a combination according to the invention.

3 shows a circuit diagram for a second embodiment of a combination according to the invention.

In the known combination of FIG. 1, the control circuit REG is located between the line deflection oscillator HAO and the switching transistor Q1, and when controlled by the control transistor Q2 is

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if

the ratio of the switching transistor between conductive and blocked Condition regulated. This regulation is limited by the requirements placed on the relationship between conductive and locked state of the drive transistor.

So that this is avoided and the relationship between the conductive and blocked state of the control transistor Q2 from Relationship between the conductive and blocked state of the switching transistor Ql is made independent, is the control transistor Q2 as shown in Figures 2 and 3, according to the invention by one additional secondary winding L3 of the transformer T is fed. Furthermore, the control loop REG has both a voltage and Current switching back on, in such a way that the supply voltage is kept constant via the capacitor C5 to the rest of the receiver and the collector current in the control transistor is limited to a certain value, which is when the combination and abnormally high load on the food source is important.

To vary the ratio between the conductive and blocked state of the control transistor Q2 completely independently of This ratio of the switching transistor Ql, the voltage from the transformer in the control loop is rectified and filtered, and the AC voltage is used to derive a sawtooth voltage, which is converted into a pulse with variable in a comparison circuit Width determined by the voltage and current switch-back is converted. This pulse then controls the regulating transistor. Such will be A voltage is formed across the capacitor C5 which is stabilized against changes in the mains voltage and load.

In a practical case, such a device mainly provided a stable voltage of 165 V across the capacitor C5 maintained in the event of mains voltage variations from 160 to over 260 V and a load variation from 0 to IA, and the control pulse to the drive transistor is constant over the entire control range compared to that which can be achieved with the circuit of FIG. what is cheap.

In addition to what is shown in FIG. 2, there is a series circuit via the compensation capacitor C1 in FIG from a resistor Rl and a capacitor C2 connected and across the capacitor C2 is one of two resistors R2 and R3 existing potentiometer connected. The capacitor C2 is charged through R1 and the voltage divider R2, R3 causes the to be charged Capacitor C3 through the switching transistor Ql. The relationship

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between the voltages across C2 and C3 is determined by the ratio between resistors R2 and R3. When the voltage across C3 reaches a value determined by the voltage-dependent saving circuit S, the line deflection oscillator HAO suddenly receives supply voltage and controls the switching transistor Ql via the capacitor CA so that the desired voltage appears across the secondary windings L2 and L3 of the transformer T.

R1 is chosen so large that the line deflection oscillator does not work continuously if C2 of none other source than Rl current is supplied. The savings circuit S interrupts the current to the line deflection oscillator when the Voltage across C2 has dropped to a limit value. This will recharge C2 and repeat the whole process. Under normal conditions, C2 receives current through a diode D1 and the device can thus operate continuously.

The setting of the ratio between the conductive and blocked state of the switching transistor Ql is selected in such a way that that the operating conditions for the drive transistor Q3 are optimal.

The designs shown are shown in series, because this is the cheapest, but parallel connection is of course also possible.

809810/0844

Claims (4)

-Λ 7739037 Claims Combined supply voltage source and line deflection circuit for television receivers that have a DC voltage converter Transformer (T) and one of the line deflection oscillator (HAO) controlled switching semiconductor (Ql), a control circuit (REG) for Setting the operating period, a control semiconductor (Q2) and a drive semiconductor (Q3) for the line deflection coil (L) comprise, characterized in that the control circuit (REG) is controlled by an additional secondary winding (L3) at the transformer (T) and the ratio of the control semiconductor (Q2) between conductive and blocked state is independent regulates the ratio of the switching semiconductor between conductive and blocked state. 2. Combination according to claim 1, characterized in that the control loop (REG) one Has voltage and current switch-back. 3. Combination according to claim 1 or 2, characterized in that the supply voltage input a series circuit of a resistor (Rl) and a capacitor (C2) is provided that over the capacitor (C2) a series circuit consisting of a voltage divider consisting of resistors (R2, R3) is provided that the tap of the voltage divider is connected to the base in the switching semiconductor (Ql) and that the stabilized supply voltage via a diode (Dl) dem Connection point between the resistor (Rl) and the capacitor (C2) in the first-mentioned series circuit is supplied. 4. Combination according to one of the preceding claims, characterized in that in the base emitter circuit of the switching semiconductor (Ql) an economy circuit (S) is inserted, which derives supply voltage and to the line deflection oscillator (HAO) delivers. 809810/0844 ORIGINAL INSPECTED