GB2198601A - Devices electrically chargeable via capacitive/inductive coupling - Google Patents

Abstract

Rechargeable reservoir A, B such as battery cells or capacitors have electrodes thereof capacitively coupled to electrodes N1, N2 of a high frequency alternating current charging source. Diodes D1, D2 cause the reservoir A, B to be respectively charged on positive and negative half cycles of the charging current and elements Z, such as inductors, block the flow of charging current to load terminals of reservoirs A, B which may be connected in series or parallel with one another with respect to the load terminals. An inductive coupling may also be provided (Fig. 5) and receiving coils may be formed by coiled polymer-laminate composite cell material. Inductive coupling may be used for recharging with capacitive coupling being used at a higher frequency for two-way data transfer. The reservoir A, B may be incorporated in powered credit cards, digital watches, calculators, games and toys. <IMAGE>

Description

Jmpwvements to Contactless electronic Conrectors This invention relates to Patent GB2149548 which descubes dual contactless electwnic assemblies capacitive coupled for the transfer of energy which includes power and 2-way.

data to, for example, wntactless electwnic memory cards commonly known as smart-cards. More specifically the present invention relates to contactless coupling of energy from a First electronic assembly to energy reservoirs of a Second electwnic assembly.

The present invention avoids the need to fabricate capacitive coupling plates which are seperate from recipient reservoirs themselves.

Accordingly, the invention comprises mears to capacitively couple recharging energy directly to reservoir electrodes, means to enable the fabrication of essentially symmetrical constructions resulting in mears to facilitate universal charger constwctions.

The invention is applicable inten alia to portable electronic second assemblies enabled to receive capacitive-coupled rechange energy through thein outen casings from insulated surfaces of first assembly universal chargers. That is to say, accumulators permanantly attached to inside casings of electronic domestics such as digital-watches calculators games tous and powered credit-cards, receive charging current when placed wither singly or in mixed multiples on the shelf of said first assembly universal charger.

Subject matten of the present invention concerns only second assemblies .

Features, objects and manner of attaining them will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with accompanying drawings.

The invention is applicable inter alia to smart-cards and otier contactless personal and portable electionic egurpments, State-of-the-art rechargeable cell material (to be discussed laten) advances the prospect of contactless rechargeability being applied to standard-thickress smart-cards and also to a wide range of personal electronic items. Overall bulk of these and particularly the thickress dimension, reguires flat surface real-estate and especially the coupling surfacearea, to be maximized.

Accordingly and to maximize coupling area, this invention eliminates the need for coupling plates and coils which are seperate from reservoir cells themselves. Taken in co@yurction with aforesaid Patent the invention comprises means to couple energy signals direct onto purpose-formed electrodes of recipient reservoin cells, means to wurk these cells in series and in parallel, improved means to full-wave rectify coupled energy signals with two insteak of four rectifien diodes and decoupling means to isolate coupled energy signals from inherent regulated output of recharging reservoirs.

The invention will now be described by way of example with reference to the accompanying drawings in which : (All electronic componets are essentially cross-referenced throughout.) Fig.1 represents a first electronic assembly in profile of which capacitive coupling plates N1 & N2 are coupled with eithen both +ve or both -ve outen electrodes of batteries betten known as accumulators A & B of a second assembly. Such reservoirs are assumed to be of large surface-to-volume ratio.

Fig.2 is the circuit diagram of fig.1. Batteries are series connected.

Fig.4 is the arrangement accorded to parallel working of A & B.

Fig.3 is an alternative arrangement of preferred embodiment fig.1.

That is to say battery A in fig.3 is reverse connected.

Fig. 5 represents in profile a generic embodiment of the invention in which a First assembly 7,8,9 covples erergy throuht a dielectric to a Second assembly.

Fig. 6 represents in plan the Second assembly in Fig.5 with corresponding references.

Figs. 7,8 and 9 are circuit diagrams which separate out and thereby simplify explantaion of sub-generic aspects and embodiments of the invention.

Fig. 7 discloses in detail the circuitry associated with essentially exclusive Capacitive coupling of energy direct onto plate electrodes of reservoirs connected for Parallel working.

Fig. 8 is a rearrangement of Fig. 7 for working reservoir cells in Series.

Fig. 9 discloses in detail the circuitry associated with essentially exclusive @nductive coupling of energy direct onto coiled electroaes of reservoirs connected for Parallel working. The Series arrangement can be derived from that in Fig. 8.

The invention being of essentially symmetrical construction with component parts having similar functions, will be more readily understood by considering functional details of the arrangement in fig.1.

Alternating current at preferred but non exclusively short-wave freguency generated by and supplied to first assembly plates N1 & N2, is coupled with a second assembly via optionally chosen electrodes. During a positive cycle at N1 coupled with +ve electrode of A, charging current is induced to flow through this battery or cell and out at -ve A. Then via diode D2 to B +ve electrode which is coupled with negative cycle N2 at that instant. Reverse current at this instant which would tend to discharge Battery B, is blocked by the combined functions of diode D1 and unspecified components designated Z. These components offen high impedance to unwantes discharge currents and will be chosen according to specific applications of the invention. Jnductive coils and / on low resistances relative to output terminal reguirements have been found suitable.

Jnternal cell capacitances shown as Ci will be especially relevant to successful practice of the invention when new technology reservoirs are being developed. This hindrance Ci which will tend to short-circuit high freguency charge currents, can be turned to advantage by being exploited to actually regulate charging currents to safe limits. Distanoe between wlectrodes during fabrication of cells batteries and other reservoirs can be chosen to suit different applications. Jt will be apparent in the art why othen specific current regulators need not be specified.

Absence of a second same-plane electrode to complete the coupling path such as with single-cell charging according to the invention, is overcome by splitting the cell into two seperate cells ana then working them in parallel. Particularly relevant eg, to digital watches.

Taken in conjunction with subject matten of aforesaid prion-art inventions, the present invention enables improved powered credit-cards in that electrodes doubling as capacitive couplers, permit more efficient use of premium real-estateon the ca@d.

Referung now to Fig.5, alternating-energy source 7,8,9 comprises metallic plates 7,9 and @nductive coil 8 which may be the secondary winding of a transformen as pant of, or separate from, the ene@gy supply to the plates. A Second assembly comprises three reservoin cells with opposite polarity outer electrodes 3/4,1/2,5/6.

Lamintae cell electrodes similarly form plates 3/4,5/6 and coil 1/2.

Plate electrodes commoned with coiled electrode extremities are cioss-connected with reverse-biased rectifien diodes D1 and D2.

The three cells are essentially in parallel with the reservoir output taken from centre-taps of the coiled electrode.

Jn orden to realize fuller significance of the invention, it should be appreciated that emergent Polymen-laminate composite cell material is both rechargeable and solid-state. @ltra-thin or stacked variable-geometry cells can be embeaded and even printed, onto inside surfaces of electronic eguipment casings.

Fig.6 therefore, is a diagrammatic laminate @lat-plane recrargeble cell with uppermost positive electrode 3,5,1, laid on negative electrode 4,2,6. Close-wound coiled cell 1/2 could be enlarged to emphasize inductance at the expense of lessen capacitance plate area 3/5, 4/6. Or conversely, and to emphasize capacitance plate area, the coil could be wire-wound to surround the plates on the flat plane, or seperate from this plane altogether.

The invention being of essentially symmetrical construction will be more readily understood by considening functional details first of capacitance coupling of energy direct to reservoir cell electrodes. Repetition will be avoided by assuming that circuit action reverses at each half-cycle of coupled energy and that coupling to eithen pain of similar-polarity cell clectrodes, is optional.

Referring now to Fig.9, an alternating-energy generator (not defined) output, fed in antiphase to metallic plates 7 and 9, couples with twin negative outen electrodes 4 and 6.

At a period in time when coupled voltage potential on 4 is highen than that on 6, rectifier diode D2 conducts and gives rise to a charging current in cell 5/6. Rectifier diode D1 is reverse biased at this time preventing discharge of cell 3/4 by the coupled signal. The cells are connected for parallel working via components z. Without these, it will be apparent that coupled energy between 4 and 6 would be short-circuit dissipated.Thus they are chosen to offer high impedance to the coupled signal but relatively low impedance to that of the load.

Fig.8 Cells 3/4 and 5/6 are series connected by lirk 10 via at leasr one Z component. Reservion output is also seriesed with at least one Z component. Cnergy coupling and cell rec@arging is similan to that described in conjunction with Fig.7. However, the circuit ma@es it plain uny component(s) Z die purposefully not referenced as optional centre-tapped coils 1/2 as in Fig.7 Component Z is now discussed in more detail. @ts primary function is to minimise short-circuit dissipation of the coupled @ignal despite parallel or series connections. Thererore, Z could be a resistance element, or a capacitance-bypassed resistance.

But in a preferred generlc embodiment, Z is an inductance element comprised of flat-plane coiled composite cell material as substantially aescribed in conyunction with Fig.6. This a@as to total reservoir capacity in a given area, and also yields useful electrical oi-products, as will now be considered : By egually distributing inductance value of Z in series with, and in both reservoir output lines as illustrated, the ocupled energy signal is substantially, if not totally, decoupled from the service load. Data in the signal can thus be read and written.

Anothen useful bi-product is that inductance value of Z can be chosen to assist tuning of the coupled network in order to maximize energy transfen according to practises @noun to those s@illed in the art.

Yet anothen bi-product, is detailed in conjunction with Fig.9.

According to the invention, flat-plane cells coiled and connected as illustrated possess the inherent potential to themselves couple to inductive component parts of the coupled energy signal.

Such coupling, could be incidental to mainly capacitive coupling or, could be purposefully empnasiged at the energy source. @t follows that by careful besign, the two forms of coupling can be adapted on the same substrate. Jnductive coupling at lower freguencies for recharging reservoirs. Capacitive coupling at highen freguencies, but at lowen energy levels to restrict nuisance radiations, for 2-way data transfer.

Fig.9 centre-tapped coiled composite cell material comprises a positive electrode 1a/1b on flat-plane negative electrode 2a/2b with coil extremities a/c and d/f cross-connected with reverse biased rectifier diodes D1 and D2. For the purpose of explanation, a theoretical family of magnetic induced voltages is shoun, referenced to c/d. without cross-connected diodes, induced voltages at a/c and d/f would effectively be iaentical. But with cross-connected diodes, the now forward biased D2 places the two coils in series, with D1 now reverse biased. Conseguently, a potential difference of 10v is set up between the two coils throughout thein lengths, giving rise to egually distributed charging current. The action reverses with opposite polarity induced voltages.Therefore, the two diodes achieve full-wave rectification of the coupled signal and also they effect an alternating switching action with useful secondary-function possibilities. One example is discussed in brief : Known constructions achieve higher coupling efficiency with series-resonant coil/tuned-capacitace arrangements. A tuned capacitance bypass caross D1 or D2, achieves this effect.

Aspects of the invention, in use, which may not already be apparent are now considered : Energy storage reservoirs in foregoing disclosures essentially include primary and secondary cells and batteries and also, capacitance stores.

Primary cells may be coupled to in the mannen accorded to the invention, for 2-way data transfen. Recharging from the coupled signal being now redundant, may be discontinued by deletion of D1,D2 and the associated cross-connection.

Apparatus powered from coupled reservoirs is decoupled from the signal source by means as substantially described. This permits the apparatus to more readily demodulate and also to modulate data on the coupled energy signal.

Demodulation means may inelude resistan@s elemerts in series with cross-coupled D1,D2, to develop the coupled signal voltage.

Modulation means may include data-modulated su@tching of similar-polarity coupled electrodes one-to-the-other. This, to effect amplitude modulation of the coupled signal, detectable at the signal source.

Test-rig embodiments of the invention may include capacitance storage elements to substitute as secondary cells. high-capacity large dimension electrolytics, capacitive-coupled via the casing electrode to an energy source, readily demonstrate the coupling of energy (with test-leads disconected) direct to reservoir electrodes.

Claims (18)

What J claim is :

1) A coupling arrangement for maximizing area of coupled surfaces between a signal source and energy storage reservoirs, including means for coupling a signal source direct onto reservoir electrodes, mears to decouple coupled electrodes from each other the decoupling means being adapted to decouple the signal source from reservoir output terminals, and means to charge rechargeable reservoirs form an energy source coupled directly to reservoir electroaes.

2) An arrangement as chaimed in claim 1 wherein coupling means comprise at least one reservoir electrode of either polarity.

3) An arrangement as claimed in claims 1 and 2 wherein decoupling means comprise at least one impedonce element in series with an inter-electrode connection the impedance being responsive to impede coupled signals and substantially less responsive to impede reservoir output energy relative to a service load impedance.

4) An arrangement as claimed in claim 1 wherein decoupling means comprise inductance elements, a preferred but non exclusive arrangement being centre-tapped inductance coils in series with inter-electrode connections with centre-taps forming reservoir output terminals.

5) An arrangement as claimed in claim 4 wherein centre-tapped coils comprise coiled reservoir electrodes as part of a decoupling arrangement.

6) An arrangement as claimed in claims 1,2 and 5 wherein rechargeable energy st@rage reservoir electrodes couple with an energy signal source and charge vin reverse-biased rectifier diodes cross-corrected between opposite polarity outer electrodes.

7) An arrangement as claimed in claims 1,4,5 and 6 wherein rechargeable coiled electrode reservoirs are cross-connected by reverse-biased rectifier diodes between extremities of opposite polarity coiled electrodes.

Claims continued :8) Arrangements as claimed in claim 6 and 7 wherein said cross connected rectifier diodes form part of a tuning arrangement to maximize power transfer from a signal source.

9) Arrangements as claimed in claims 3,4, and 5 wherein the decoupling means forms port of unspecified arrangements to demodulate and modulate data on the energy source signal.

10) An arrangement as claimed in claim 1 and 2 wherein the coupling means is adapted to permit the juxtaposition, in use, of the coupled assembly any-way-up and any-way-round, to a companion signal source gssembly.

11) An arrangement as claimed in any preceding claim wherein propagated energy source signals being inherently comprised of electric and magnetic field components, couple respectively and by predetermined degrees to Capacitive elements and to Jnductive elements of the coupled assembly.

12) An arrangement as claimed in claim 8 wherein repective.

degrees of Capacitive and Jnductice coupling are selectively determined at the energy signal source to thereby address the signal to a selective function.

13) Capacitively-coupled assemblies characterized by the coupling of charging-current directly to elkectrodes of associated reservoirs, means to cyclically isolate electrodes of a first reservoir to enable charging of a second reservoir, means to work said reservoirs in series or in parallel, means to exploit otherwise parasitic inter-electrode capacitances to become charge-current regulators and means to facilitate universal charger constructions.

14)Assemblies as claim 13 in which means to cyclically alter the main purpose of an electrode to that of coupling-plate comprises arrangements to restrict reverse-charge currents in said first reservoir during cyclical charge periods of a second reservoir.

15) Arrangements as in claim 14 comprising blocking diodes cross connected between coupling electrodes of a first reservoir and non-coupling electrodes of a second reservoir and also including undefined blocking components connected into alternative reverse charge paths to set up high impedance blocks while simultaneously not significantly altering reservoir output characteristics.

16)Assemblies as in claim 13in which means to work said reservoirs in series or in parallel are as substantially described.

17) Assemblies as in claim 13in which means to exploit inter electrode capacitances to act as charge-current regulators includes means to adjust degrees of regulation by. altering said c@pacitance values during fabrication of reservoirs.

18) Assemblies as in claim 13in which means to facilitate uriversal charger constructions comprise essentially symmetrical constructions as substantially described and illustrated in figs. 1 to 4 of second assemblies to minimise coupling alignment and orientation reguinements.