DE1180777B - Magnetically coupled multivibrator - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: H 03 k

German class: 21 al - 36/02

Number: File number: Filing date: Display date:

G 35733 VIII a / 21 al August 17, 1962 November 5, 1964

The invention relates to magnetically coupled multivibrators having two transistors and two Magnetic cores with a rectangular hysteresis loop.

A magnetically coupled multivibrator is already known in which the circuit is similar to the a free-running multivibrator in which two transistors are connected in push-pull and through Feedback is operated, is designed. The feedback comes from windings that are on attached to the same saturable core as the primary windings. With such a circuit a highly retentive core is used to control the switching of the transistors. The operation is therefore dependent on the saturation of the core from kink to kink.

To avoid the disadvantages of such a multivibrator, two have already been proposed to use highly retentive cores to make the switching independent of the kink-to-kink saturation close. Each core is only saturated in one kink and during the other half-cycle reset. This allows a core to saturate through feedback from the transistor it controls

Magnetically coupled multivibrator

Applicant: General Motors Corporation, Detroit, Mich.

(V. St. A.) Representative: Dr. W. Müller-Bore and Dipl.-Ing. H. Gralfs, Patent attorneys, Braunschweig, Am Bürgerpark

Named Inventor: Wayne Eugene Damon, Martinsville, Ind.

(V. St. A.)

Claimed priority: V. St. v. America August 21, 1961 (132 943)

and that in each collector line of the two transistors two parallel connected, placed in opposite directions are arranged while the inactive core is 25 rewound inductors, of which is provided. The latter process is inductive associated with one of the two magnetic cores Coupling achieved, the secondary being net.

winding of the active core so on the secondary In the control windings of an inventive

Winding of the inactive core has the effect that the multivibrators are simultaneously equal and entder the former induced current in the latter so induced 30 oppositely directed voltages. this is directed that the inactive core is reset. takes place by the alternating connection of the par-Es has also been proposed to size allelically switched pairs of windings on the two the resetting by a control current and control - separated cores with the energy source, to regulate windings. Such control circuits have, however, the cores transmit the same magnet circulating currents on which a control source 35 tables flow, and the current from the energy source require low impedance. The aim of the invention is according to the flow requirements of each core and the a magnetically coupled multivibrator that divides the load. Neither the control windings The limiting disadvantages of the known arrangements therefore still require the bias windings gen does not have. Current to compensate for changes in flow in the core,

A magnetically coupled multivibrator according to 40 and the frequency control source can have a high
Energy source are connected via a first and second transistor, which can conduct current and 45
alternate the first and the second core in
bring saturation, the circuit being designed so that in the primary windings simultaneously
Current flows, for one core in saturation

50 multivibrator with adjustable frequency contains two device that the first and the second primary winding highly retentive cores 10 and 12 and two Schaltmit connected to a pair of output terminals, transistors 14 and 16. On core 10 are primary

409 710/354

directions.

The invention is described below in connection with the drawing figures.

Fig. 1 is a circuit diagram of a multivibrator according to the invention;

Fig. 2 shows the circuit diagram of a further multivibrator according to the invention. The in F i g. 1 illustrated magnetically coupled

3 4

windings 18 and 20, a feedback winding The frequency of the magnetically coupled Multi-22, a control winding 24 and a bias vibrator according to FIG. 1 are dependent on the reverse winding 26 wrapped. The core 12 carries the primary position of the cores 10 and 12. The reset can windings 28 and 30, a feedback winding by changing the magnitude and direction of the current, 32, a control winding 34 and a bias voltage 5 through the control loop with the current regulating winding 36. Transistor 14 has a base 38, a device 58, and control windings 24 and 34 Collector 40 and an emitter 42. Transistor 16 flows, can be changed. For example, if the has a base 44, a collector 46 and a counter-clockwise current in the control loop, so Emitter 48 on. It supports the resetting in the cores 10 of the emitter electrodes 42 and 48 are common to the negative terminal of an io and 12 and sets the frequency of the multivibrator Battery 50 connected. The primary windings 18 come down. However, if the current flows in the loop in and 28 are connected in parallel and lie between the pointer sense, so it hinders the resetting of the the positive terminal of the battery 50 and the cores 10 and 12, so that the frequency of the multivi-collector 46 of transistor 16. The primary winding generator rises. A lower frequency limit can be Gen 20 and 30 are connected in parallel and are 15 by using a bias control loop between the positive terminal of battery 50 and to the bias source 60 and the bias Collector 40 of transistor 14. Voltage windings 26 and 36 are created. Divider circuit with the resistors 52 and 54 through the level of saturation of the cores 10 supplies the transistors 14 and 16 via resistor 12 and 12 set.

56 and feedback windings 22 and 32, respectively, which shows 20 Another embodiment of the invention

are connected to the base electrodes 38 and 44, the circuit diagram according to FIG. 2. The one shown here

a bias. The multivibrator bias windings 26 has two highly retentive cores 100

and 36 are connected in series and form with those and 102 and two switching transistors 104 and 106

Bias source 60 and a resistor 62. Core 100 carries a primary winding 108, one

a closed loop. The winding sense of the control winding 110, a feedback winding 112

Windings on the cores 10 and 12 is through and a bias winding 114. Core 102 has

Points indicated. The output of the multivi- a primary winding 116, a control winding 118,

brators is supplied by terminals 64 and 66, which are provided with a feedback winding 120 and a bias

the common terminals of the voltage winding 122 connected in parallel. Transistor 104 has a base

Primary windings 18 and 28 or 20 and 30 connect 30 124, a collector 126 and an emitter 128.

are bound. Transistor 106 has a base 130, a collector

,. . 132 and an emitter 134. The two emitters

Operation _{128 and 134 are with the positive} terminal of the

Assume that transistor 14 is currently connected to battery 136 in the conductive state. The primary windings 108 become, and the transistor 16 is blocked. Tran- 35 and 116 are connected in parallel and lie between transistor 14 then remains conductive, as indicated by the in collector 126 of transistor 104 and collector 132 Feedback winding 22 induced feedback of transistor 106. A voltage divider circuit voltage predetermined until core 10 is saturated. from resistors 138 and 140 provides the tranin At this point in time, the inductors 104 and 106 in winding 22 drop across resistor 142 and the ed feedback voltage suddenly to zero. 40 feedback windings 112 and 120, which are connected to the The flux in the saturated core 10 falls on its bases 124 and 130 respectively, a bias residual and induces a low voltage. The bias windings 114 and 122 in the feedback winding 22, the polarity of which are connected in series and form a loop with is that the base 38 has a negative voltage applied to a resistor 144, the battery 136 and a leads, which blocks the transistor 14 further. 45 Bias control resistor 146. The Steuerwick-Simultaneously a low feedback voltages 110 and 118 are connected in series and voltage induced in the feedback winding 32, form a loop with a Stromregeleinrichderen The polarity is such that the base 44 has a slight direction 148.

positive voltage is applied so that transistor A non-saturable power transformer 150

16 becomes conductive and conducts until core 12 is saturated 50 has a primary winding 152 tapped in the middle,

and a new period begins. its upper half with 154 and its lower half

In the half cycle while transistor 14 is designated 156. The negative terminal of the

is conductive, the voltage from the battery 50 is the battery 136 with the center tap 151 of the

the primary windings 20 and 30 primary winding 152 connected in parallel. Collector 126 of the

fed so that the current in the primary winding 20 is 55 transistor 104 to the outer terminal of the

for the core 10 in the saturation direction and connected in the upper half 154, while collector 132

Primary winding 30 for core 12 in reset of transistor 106 with the outer terminal of the lower

direction flows. Therefore, the resetting of the ren half 156 is connected to the primary winding 152

Core 12 by galvanic coupling which is parallel. The winding sense of the windings on the

switched primary windings 20 and 30 achieved. In 60 cores 100 and 102 it is indicated by dots,

in the same way flows during the period in which the multivibrator output can over the terminals

Transistor 16 conducts and transistor 14 is blocked, 160 and 162 of an output winding 158 of the trans-

a current can be drawn into saturation transformer 150 through primary winding 28,

direction for the core 12 and in the primary winding. The operation of the circuit according to FIG. 2 is

a current in the reset direction for the core 10. 65 similar to that of FIG. 1. Assuming that the

The transistor 104 removed from terminals 64 and 66 has just become conductive and

The output variable corresponds to the switching mode of the Tran transistor 106 blocked, so transistor 104 remains that way

transistors 14 and 16. long conductive, as provided by those in winding 112

induced feedback voltage is given. The upper half 154 of the primary winding 152 is supplied with a voltage, the value of which corresponds approximately to the battery voltage of the battery 136. The transformer effect induces a voltage in the lower half 156 of the primary winding 152 , so that a total voltage of approximately twice the size of the battery voltage 136 occurs across the entire primary winding 152 . This voltage is in turn fed to the primary windings 108 and 116 connected in parallel. The current flowing in these windings has the saturation direction for the core 100 and the reset direction for the core 102. If core 100 is saturated, the feedback voltage induced in winding 112 suddenly drops to zero, as a result of which transistor 104 becomes non-conductive. The flux in core 100 then drops to its residual value, inducing a small voltage in feedback winding 112 and applying a positive voltage to base 124 which further blocks transistor 104. At the same time, a small feedback voltage is induced in the winding 120 , as a result of which a negative voltage is fed to the base 130 , so that the transistor 106 becomes conductive. Transistor 106 remains conductive until core 102 is saturated and a new period begins. The frequency of the voltage at output terminals 160 and 162 is dependent on the resetting of cores 100 and 102. The reset can be controlled by changing the magnitude and direction of the current flowing through the control loop comprising control windings 110 and 118 and current regulator 148. If the current flows in the counter-clockwise direction in the control loop, it supports the resetting of the cores 100 and 102 and reduces the frequency of the multivibrator. If, however, the current in the loop flows in the pointer direction, the resetting of the cores 100 and 102 is hindered, which results in an increase in the multivibrator frequency. A lower operating frequency limit can be established through a bias control loop having the bias source 136 in series with the bias windings 114 and 122, a variable resistor 146 and a resistor 144 . The level of saturation of the cores 100 and 102 is thereby predetermined.

Claims (6)

Patent claims: 1. Magnetically coupled multivibrator with two transistors and two magnetic cores with a rectangular hysteresis loop, characterized in that first and second parallel-connected primary windings (18, 20, 30, 32; 108, 116) are wound on these magnetic cores, which are connected to an energy source first and second transistors (14, 16; 104, 106) are connected which can conduct current and alternately bring the first and second core into saturation, the circuit being designed so that current flows in the primary windings simultaneously, namely for one core in the saturation direction and for the other core in the reset direction, that the first and second primary windings are connected to a pair of output terminals (64, 66; 160, 162) and that in each collector line of the two transistors two parallel-connected, opposing directions wound inductors are arranged, each of which is assigned to one of the two magnetic cores. 2. Multivibrator according to claim 1, characterized in that each core (10, 12) carries a pair of primary windings (18, 20; 28, 30) , a first primary winding of one core being connected to a second primary winding of the other core. 3. Multivibrator according to claim 1 or 2, characterized in that each core has a control winding (24, 34; 110, 118) and that these control windings are connected in series. 4. Multivibrator according to claim 2 or 3, characterized in that a current regulating device (58, 148) is connected in series with the control windings. 5. Multivibrator according to claim 1 to 3, characterized in that each core has a feedback winding (22, 32; 112, 120) , and that these windings are arranged so that they support the alternating operation of the switching devices. 6. Multivibrator according to claim 1, characterized in that the emitters (42, 48,128,134) of the transistors are connected to one another and via the energy source (50, 136) are coupled to the primary windings, that the collectors (40, 46; 126, 132) of the Transistors are connected to the energy source via the primary winding on the first core and the primary winding on the second core and that the feedback windings (22, 32, 112, 120) on the first and second core connect the emitter and base electrodes of the first and the second transistor, respectively . Considered publications:
U.S. Patent No. 2,939,115. 1 sheet of drawings 409 710ß54 10.64 © Bundesdruckerei Berlin