DE2511398A1 - Pulse generator with a transformer - has primary winding in the oscillator circuit and secondary winding in charging circuit - Google Patents

Abstract

The charging circuit includes a capacitor and a diode, with the capacitor also connected to the primary winding of a second transformer in a discharge circuit when a switch is closed, so that a pulse is generated in the second transformer secondary winding by the capacitor discharge. The capacitor discharge circuit contains a part of, or the whole secondary winding of the first transformer, the primary winding of the second transformer and the switch make contact. The oscillator is a transistorised blocking convertor. The power supply is typically a 1.5 volt battery. The battery positive terminal connection to the first transformer forms a ringing choke action, the intermediate connection to the coils being connected to the common line through a transistor and Zener diode which are in parallel with one another.

Description

"Pulse generator circuit" The invention relates to a pulse generator circuit and in particular to a circuit for generating a high voltage pulse, with which the gas from a gas lighter can be ignited, which circuit from a Source of low DC voltage is fed.

The invention provides a pulse generator circuit having a first Transformer, whose primary winding is included in an oscillator circuit and whose Secondary winding connected to a capacitor and a diode in a charging path is, the capacitor connected to the primary winding of a second transformer in a discharge path is connected when a switch is put into operation, which leads to The consequence is that a pulse passes through a secondary winding of the second transformer when discharging of the capacitor is generated, characterized in that that the discharge path of the capacitor is part of the secondary winding of the first Transformer or this entire winding.

The invention is illustrated below for an exemplary embodiment the drawing explains in more detail, which is a circuit diagram of a pulse generator circuit represents.

An oscillator circuit is created by a transistor TR1, windings L1, J2 of a transformer T1, a diode D1, a zener diode D2 and a resistor R1 formed. A battery B1 supplies a low DC supply voltage and can can be connected to the oscillator via a terminal 1 of a switch S.

Another winding D3 of the transformer T1 is with a diode D3 and a primary winding J4 of a second transformer T2 connected in series and forms a charging path for a capacitor C.

One. Secondary winding T of transformer T2 is over one Alnken stretch S.G. arranged as is symbolically indicated. An unloading line for the capacitor C is through the winding J.3 of the first transformer T1, the switch in position 2 and the primary winding J4 of the transformer T2 formed.

The mode of operation of the circuit is the following. the The rest position of the switch S is the hunt 2 and in a preferred embodiment the switch is arranged in such a way that it is directed towards this position by a spring is biased. The switch S is moved to position 1 when it is started up and is then connected to the series arrangement of resistor R1 and diode U1 Battery B connected.

The diode D1 is a bias stabilizer because it has a Voltage drop equal to the Vbe voltage of the transistor TR1 occurs, whereby the Oscillator can work with a strongly changing supply voltage. This is of particular importance with low supply voltages of e.g. 1.5 V from the battery B.

The transistor TR1 becomes conductive and is due to the coupling 'between the coils J1 and 12 of the transformer T1 by the known in flyback converters Occurring inductive feedback (ringing choke action) blocked again.

When the transistor TRl is conductive, the coils J1 and store J2 energy while this energy, when the transistor TR1 is blocked, over the Winding J3 is transferred to the capacitor C, the diode D3 preventing that energy flows from the capacitor C via the winding J4.

With continued inductive feedback, the capacitor C charged, so that the voltage across the capacitor C is rocked.

If this process were to continue, the nominal voltage of the capacitor should be C can easily be exceeded, for which reason the zener diode "D2" in the oscillator circuit is added to the collector modulation of the transistor TR1 and thus the transformed voltage that charges the capacitor C to limit.

When capacitor C charges, switch S becomes its Rest position 2 returned.

Now the winding J3, the switch S and the primary winding J4 of the transformer T2 forms a discharge path for the capacitor. Above the spark gap S.G. a spark is now generated because for the transformer T2 a high build-up ratio (almost 1:30) is selected. For further training it is also possible to ensure that the blocking oscillator is always effective and discharge the capacitor using a single normally open switch will.

One advantage of using the winding is in the unloading section in the application of the spark that occurs when a gas / air mixture is ignited, as in gas lighters or used in gas cooking appliances. The winding J3 becomes namely get a leakage inductance that the initial surge in the Primary winding J4 controls, which has the consequence that the spark current is regulated in this way being that a fluke longer duration with a lower one energy is delivered. It has been shown that such a spark for gas ignition is the otherwise obtained sparks of short duration and high energy are preferable.

The winding L3 also causes the peak current to flow through the contact 2 is significantly reduced, making it possible to have a smaller contact use. In a practical exemplary embodiment of the system, this current is reduced from 40 A to 6 A. As you can normally expect the contact bounces, the reliability of such contact is reduced by the degradation of the stream enlarged.

In a further embodiment, the contact 2 of the switch S be connected to a tap on the secondary winding of transformer T1, as shown in dashed lines. This allows a compromise between the discharge part the inductance of L3 and the inductance of the primary winding 14 can be obtained, whereby a better compromise between the initial spark current and the duration of the Spark can be obtained.

Claims (7)

PATENT CLAIMS: (1) Pulse generator circuit with a first transformer whose Primary winding included in an oscillator circuit and its secondary winding is connected to a capacitor and a diode in a charging path, wherein the capacitor with the primary winding of a second transformer in a discharge path when a switch is put into operation, which has the consequence that a Pulse through a secondary winding of the second transformer when discharging the Capacitor is generated, characterized in that the discharge path of the capacitor part or all of the secondary winding of the first transformer contains. 2. Pulse generator circuit according to claim 1, characterized in that that said discharge path from the capacitor, part or all of it Secondary winding of the first transformer, the primary winding of the second transformer and an activated normally open contact of the switch exists. 3. Pulse generator circuit according to claim 1 or 2, characterized in that that the oscillator is a transistorized flyback converter with a single switching transistor is. 4. pulse generator circuit according to claim 3, characterized in that that the primary winding of the first transformer in the collector circuit of the switch transistor is added, and that a feedback winding that is inductive with the said Primary winding of the first transformer is coupled in the base circuit of the switching transistor is recorded. 5. pulse generator circuit according to claim 4, characterized in that that a diode is used to bias the switching transistor. 6. pulse generator circuit according to claim 4, characterized in that that it contains a zener diode connected to the collector of the transistor in order to to limit the collector voltage. 7. Pulse generator circuit according to one or more of the preceding Claims1 characterized in that the switch is a two-position switch, which excites the oscillator circuit in a first cheek and causes it in a second position, that the pulse is generated by completing the discharge path. L e r s e i t e