US3438014A - Magnetic core counting circuit - Google Patents

Description

April 8, 1969 A REGAL/4 3,438,014

MAGNETIC CORE COUNTING CIRCUIT Filed May 27, 1965 INVENTOR. A LBERT REGALADO ATTORNEY United States Patent Ofi ice 3,438,014 Patented Apr. 8, 1969 US. Cl. 340-474 Claims ABSTRACT OF THE DISCLOSURE A magnetic core circuit including a first core and a second core coupled together by a coupling circuit. The first core can be set and reset and can generate output pulses of resultant opposite polarities in the coupling circuit when it is set or reset. The circuit path includes two oppositely wound windings on the second core which generate currents which oppose and cancel each other whenever the output pulse has one polarity. However, when the output pulse has the opposite polarity, only one of the two windings is operative and it permits the pulse to be applied to and operate the second core.

This invention relates, in general, to magnetic storage devices and, particularly, to magnetic devices which are operable as counting devices in a counting circuit.

Magnetic devices, or magnetic cores as they are known, which are useful as counters have rectangular or square loop hysteresis curves. With such a hysteresis curve, a magnetic core has a maximum positive flux retentivity state, a positive remanent state, and a maximum negative flux retentivity state, a negative remanent state. In addition, such a core can be energized in increments, and it can be stepped along its hysteresis curve from the maximum negative state to the maximum positive state in steps, each of which represents a stable operating state. The number of steps through which a core can be driven may be varied over a wide range as desired. One circuit of this type is described in 'U.S. Patent No. 3,102,239 of Chen and Tracy.

The magnetic core counters described in the Chen-Tracy patent include at least two square loop, magnetic cores, one called a quantizing core or driving core for generating pulses of constant amplitude and duration and the other called a count core, coupled together by a unidirectional current transfer loop. In a counter which comprises many stages including a first quantizing core and a plurality of count cores, each count core also operates as a quantizing or driving core for the next adjacent count core, with a unidirectional current transfer loop provided between each pair of cores. Each core, when it operates as a quantizing or driving core, applies pulses to the associated count core, and, after a certain number of pulses have been applied, the driven count core switches, goes through a relatively large reverse flux change, and provides an output pulse.

The circuit loop which interconnects two cores must meet certain requirements, and various circuit loop configurations have been developed for interconnecting the several cores in a multi-stage magnetic core counter. All of these loops are unidirectional transfer loops and include means for preventing a counting core from being affected by spurious signals. In particular, they are aimed at preventing one core from receiving spurious signals and changing state when an adjacent core experiences a reverse flux change. A problem can arise in these circuits when one core in the series is switched from one state to another, since currents are generated which flow in the forward loop to the next core and in the reverse loop to the preceding core. The reverse current flow may affect the preceding core and provide a spurious change in state. This adverse effect is particularly likely to occur when the preceding core is a counting core.

In the past, this problem has been solved to a certain extent by the provision of a diode placed in parallel with the core windings in the transfer loop between adjacent cores to bypass some of the disturbing current. This solution is only partially effective. Another solution comprises the provision of a transistor in the transfer loop, with the transistor being oriented so that it can only be turned on by the output of the quantizing stage. This solution has been found to be more effective than the first; however, it is undesirably expensive and is not completely effective, primarily because of the time required to turn off the transistor once it has been turned on.

Accordingly, the objects of the present invention concern the provision of an improved magnetic core counting circuit having novel means for preventing currents generated by a counting core from adversely affecting any other core in the counter.

Other objects of the invention concern the provision of an improved magnetic core counting circuit which includes a counting core and a driving core for applying counting pulses thereto, the cores being coupled together by a curret flow loop including novel means for insuring the proper transfer of pulses from one core to another.

The objects of the present invention also concern the provision of an improved magnetic core counting circuit which includes a plurality of core stages coupled together by circuit loops with means provided for preventing the spurious energizing of one core when any other core is switched or otherwise experiences a flux change.

Briefly, a circuit embodying the invention includes at least two cores, one operable as a quantizing or driving core and having an output winding, and the other operable as a counting core and having an input winding. The two cores have rectangular hysteresis loops, and said output and input windings are interconnected by a unidirectional current flow loop. For the most part, the cores and the coupling circuit between them may be identical to the circuits described in the Chen-Tracy patent. However, according to the invention, in order to insure the proper transfer of signals from one core to another, an auxiliary winding is provided in the current flow loop, and this auxiliary winding is so oriented with respect to the other windings that proper interaction of two adjacent cores is achieved.

The invention is described in greater detail by reference to the drawing wherein the single figure is a schematic representation of a magnetic core counting circuit embodying the invention.

In the following description of the invention, a dot convention is used associated with the core windings to denote the direction of winding of the various coils coupled to the cores. In this convention, current into the dot end of a winding tends to establish one fiux polarity of a Core, and current out of a dot end tends to establish the opposite polarity. In addition, current into the dot end of one winding induces current out of the dot end of any other winding on the same core; thus the voltage induced on the dot end will be opposite that on the associated non-dot end of any one winding.

Referring to the drawing, a magnetic counting circuit 10 embodying the invention comprises, in series, a quan tizing magnetic core 20 and one or more counting magnetic cores 120, 220, etc. For purposes of illustration, two counting cores and 220 are shown. Each of the magnetic cores 20, 120, and 220 has a substantially rectangular hysteresis loop and, therefore, has a plurality of stable operating states of magnetic remanence.

The quantizing core 20 has three windings 34, 36, and

38 coupled thereto, with winding 34 being an input winding coupled to a source 44 of input or set pulses for switching the core from its maximum negative remanent state to it maximum positive remanent state. Winding 36 is a reset winding and is coupled to a source 50 of reset pulses which serve to reset or switch the core from the aforementioned positive remanant state to the negative remanant state. Winding 38 is an output winding in which pulses are generated each time the core 20 is set and reset. However, the circuit loop 54 associated with the output winding 38 is designed to utilize only the output pulse generated by resetting of the core 20, as will be described below.

The counting core 120 similarly includes an input winding 134, a reset winding 136, and an output winding 138. The reset winding 136 is coupled to a source 151} of pulses for resetting the core from its positive remanent state to its negative remanent state. The input winding 134 is coupled through a circuit loop to the output winding 38 of the quantizing core 20. The input winding 134 of the counting core 120 is wound oppositely to the output winding of the core 20, and the non-dot end of the output winding 38 of the core 20 is directly connected to the dot end of the input Winding 134 of core 120. The non-dot end of the input winding of the core 120 is connected through a resistive path 58 to the dot end of the output winding 38 of core 20. In addition, according to the invention, an auxiliary winding 60 is provided on counting core 120. The auxiliary winding 60 is wound oppositely to the inpu winding 134 on the core 120 and is thus 180 out of phase therewith. The non-dot end of the auxiliary winding 60 is connected to the non-dot end of the output winding 33 of the core 20 and to the dot end of the input winding 134 of core 120. The dot end of the auxiliary winding 60 is connected through a unidirectional current flow device, for example, a diode 66 oriented as shown, to the dot end of the output winding of core 20.

Core 220, like core 120, includes an input or set winding 234, a reset winding 236, and an output winding 238. A source 250 of reset pulses is coupled to reset winding 236, and a coupling loop 154, identical to loop 54, is coupled between output winding 138 of core 120 and input winding 234 of core 220. The loop 154 includes auxiliary winding 16!) and diode 166 and, in addition, resistive path 158 which couples winding 234 to Winding 138. If the counting circuit includes additional cores, then similar coupling circuits would be provided.

In operation of the counting circuit 10, initially, all of the cores are in the maximum negative remanent state. Input or set pulses are applied to core by source 54), and each time that the quantizing core 20 is set to its maximum positive remanent state by a pulse from source 44, an output pulse is generated in the output winding 33 and output current flows out of the non-dot end of the output winding. This current divides and flows through the auxiliary winding 60 and through the input winding 134 of core 120. Since the windings 60 and 134 are 180 out of phase with each other, the currents oppose and cancel each other, and core 120 is not affected. It is clear, of course, that the windings have the necessary number of turns and that their paths have the proper Overall resistances to achieve the desired cancellation. However, when a reset pulse is applied to quantizing core 20 from source 50 to drive it to its maximum negative remanent state, current flows out of the dot end of out-put Winding 38 and is blocked from entering the auxiliary winding 60 by the diode 66, but it flows through the resistive path 58 and through the input winding 134 of core and energizes the core 120 by an incremental amount as described in the above-identified patent. Thus, each time that the core 20 is reset, the care 124 is energized by an incremental amount until it reaches its state of maximum positive remanence. At this time, the core 120 is reset by a pulse from source 150, and an output pulse energizes core 220 incrementally in the same Way that an output pulse from core 20 energizes core 120.

According to the invention as described above, when core 126 is reset and generates an output pulse, it also tends to generate a current pulse in its input winding 134 which might adversely affect the core 20 if the auxiliary winding were not present. However, an equal and opposite current is generated in the circuit path including the auxiliary winding 60, and these two feedback currents cancel each other, and core 20 is not adversely aifected. The auxiliary winding 169 performs the same action in circuit loop 154 as it does in loop 54 so that core 120 is protected when core 226 is reset.

What is claimed is:

1. A magnetic core circuit including a first magnetic switching core and a second magnetic switching core,

a circuit path coupling said first core to said second core,

an output winding on said first core and in said circuit path for generating a first output pulse of one polarity or a second output pulse of the opposite polarity, the polarity being determined by input pulses applied thereto,

said circuit path including two circuit loops connected in parallel and each including said output winding on said first core,

said loops being arranged so that currents which are induced in each at the same time in response to said first output pulse flow in opposite directions and cancel each other and thus do not electrically affect said second core,

said loops also having auxiliary circuit means such that current flow in said circuit path in response to said second output pulse appears only in one of said loops and can electrically afiect said second core.

2. The circuit defined in claim 1 wherein said auxiliary circuit means includes a unidirectional current flow element in one of said loops.

3. The circuit defined in claim 1 wherein said auxiliary circuit means includes a diode in one of said loops.

4. The circuit defined in claim 1 wherein each of said parallel circuit loops includes a separate winding on said second core, said windings being oppositely wound to generate said opposite currents.

5. The circuit defined in claim 1 wherein each of said parallel circuit loops includes a separate winding on said second core, said separate windings being oppositely wound to generate said opposite currents, said parallel paths also being arranged so said opposite currents are also substantially equal.

6. A magnetic core circuit including a first magnetic core and a second magnetic core,

input, output, and reset windings on said first core,

input, output, and reset windings on said second core,

a circut path coupling said output winding on said first core to said input winding on said second core,

said circuit path including two circuit loops coupled in parallel and each including said output winding on said first core, said loops being arranged so that currents which are induced in each at the same time flow in opposite directions and cancel each other and thus do not afiect said output winding and said first core.

7. A magnetic core circuit including a first magnetic core and a second magnetic core,

input, output, and reset windings on said first core,

input, output, and reset windings on said second core,

a circuit path coupling said output winding on said first core to said second core,

said circuit path including two circuit loops coupled in parallel, on loop including said output winding on said first core and said input winding on said second core, and the other loop including said output winding on said first core and an auxiliary Winding on said second core and a unidirectional current flow device, said loops being arranged so that currents which are induced in each at the same time flow in 5 6 opposite directions and cancel each other and thus said input and output windings on said first core and do not affect said output winding and said first core. said auxiliary winding being wound in the same di- 8. The circuit defined in claim 7 wherein said auxiliary rection so that an output pulse generated by said winding and said input winding on said second core are first core, in response to a signal applied to said input wound in opposite directions. winding, flows into said oppositely Wound auxiliary 9. The circuit defined in claim 7 wherein said auxiliary 5 winding and input winding on said second core and winding and said input winding on said second core are therefore has no effect on said second core. Wound in opposite directions,

said unidirectional current flow device comprising a di- References Cited iJdC oriinted to bltock lcurrent flclxwdtlzrouglcl1 iitis circuit 10 UNITED STATES PATENTS 00p w en a rese pu se is app 1e 0 san rs core and an output pulse appears in the output winding of ggii 01 2 Thompson 340 174 said first core, said output pulse appearing in said 1 Woo 34O 174 input windin of said second core. 4 10. The circuit defined in claim 7 wherein said aux- 15 BERNARD KONICKPHma'y iliary winding and said input Winding on said second core GARY M. HOFFMAN, Assistant Examiner. are wound in opposite directions,

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