RESONANCE-COUPLED SIGNALING BETWEEN IC MODULES
Coupled resonators for galvanically isolated signaling between integrated circuit modules. An illustrative system embodiment includes first and second integrated circuits. The first integrated circuit includes: a transmitter that produces a modulated carrier signal on a primary conductor; a first transfer conductor connected to a first connection terminal; and a first floating loop electromagnetically coupled to the primary conductor and to the transfer conductor to convey the modulated carrier. The second integrated circuit includes: a second transfer conductor connected to a second connection terminal, the second connection terminal being electrically connected to the first connection terminal; a receiver that demodulates the modulated carrier signal; and a second floating loop electromagnetically coupled to the second transfer conductor and to the receiver to convey the modulated carrier signal to the receiver. The first and second floating loops are each resonant at the carrier frequency to provide resonance-coupled signalling between the integrated circuits.
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The present application is a continuation of U.S. patent application Ser. No. 15/296,627, filed 2016 Oct. 18, which is hereby incorporated by reference herein in its entirety. The present application further relates to U.S. patent application Ser. No. 15/296,660 titled “Receiver for Resonance-Coupled Signaling” by inventors Karel Ptacek and Richard Burton, and filed 2016 Oct. 18.
BACKGROUNDIntegrated circuit designers often segregate device components into different modules. Such modularization can reduce fabrication costs and improve system performance. For example, a power converter may include power MOSFETs and other components designed for higher voltages and current loads, as well as small feature-size CMOS logic gates designed for fast control operations with minimal quiescent currents. An integrated circuit designer may choose to segregate the logic components from the power components to prevent the power components from damaging or interfering with the operations of the logic components. If such modules are placed on separate substrates, the manufacturing process applied to each substrate can be tailored for the types of components in each module, thereby minimizing the areal and cost requirements associated with each module while optimizing performance.
During the packaging process, the modules are interconnected as needed to form the desired integrated circuit device. In many cases, it is desirable for these inter-module connections to provide galvanic isolation. Existing techniques such as capacitors, transformers, magnetoresistive couplers, and optoisolators, are each believed to offer insufficient reliability, excessive propagation delay, excessive bulk, and/or excessive attenuation.
SUMMARYAccordingly, there are disclosed herein various resonance-coupled configurations and methods employing coupled resonators for galvanically isolated signaling between integrated circuit modules. One illustrative system embodiment includes: a first integrated circuit and a second integrated circuit. The first integrated circuit includes: a transmitter that modulates a carrier signal having a carrier frequency to produce a modulated carrier signal on a primary conductor; a first transfer conductor connected to a first connection terminal; and a first floating loop electromagnetically coupled to the primary conductor and electromagnetically coupled to the transfer conductor to convey the modulated carrier signal from the primary conductor to the transfer conductor. The second integrated circuit includes: a second transfer conductor connected to a second connection terminal, the second connection terminal being electrically connected to the first connection terminal; a receiver that demodulates the modulated carrier signal; and a second floating loop electromagnetically coupled to the second transfer conductor and electromagnetic coupled to the receiver to convey the modulated carrier signal from the second transfer conductor to the receiver. Notably, the first and second floating loops are each resonant at the carrier frequency to provide resonance-coupled signalling between the integrated circuits.
An illustrative method embodiment includes: (a) equipping a first integrated circuit with a transmitter that modulates a carrier signal having a carrier frequency to produce a modulated carrier signal on a primary conductor; (b) equipping a second integrated circuit with a receiver that demodulates the modulated carrier signal; and (c) electromagnetically coupling the transmitter to the receiver using a resonantly-coupled signal path. The resonantly-coupled signal path has: a first floating loop that is resonant at the carrier frequency in the first integrated circuit; a transfer loop that is not resonant at the carrier frequency; and a second floating loop that is resonant at the carrier frequency in the second integrated circuit.
In an illustrative integrated circuit embodiment for galvanically isolated signaling via a connection terminal, the integrated circuit icnludes: a transfer conductor connected to the connection terminal; a transmitter that modulates a carrier signal having a carrier frequency to produce a modulated carrier signal; and a floating loop electromagnetically coupled to the transmitter and to the transfer conductor to convey the modulated carrier signal from the transmitter to the transfer conductor, the floating loop being resonant at the carrier frequency.
Each of the foregoing embodiments may be employed individually or in combination, together with any one or more of the following features in any suitable combination: 1. the first floating loop shares a common metallization layer with the primary conductor and the first transfer conductor. 2. the second floating loop shares a common metallization layer with the second transfer conductor. 3. the first and second floating loops each include an integrated metal-insulator-metal plate capacitor. 4. the first and second transfer conductors are part of a closed, floating transfer loop. 5. the first connection terminal and the second connection terminal are coupled via a bond wire. 6. the transfer loop is not resonant at the carrier frequency. 7. the transmitter is configured to receive a digital signal and to responsively produce pulses in the modulated carrier signal. 8. the transfer loop includes a first transfer conductor in the first integrated circuit and a second transfer conductor in the second integrated circuit. 9. the transfer loop further includes a first terminal connected to the first transfer conductor, a second terminal connected to the second transfer conductor, and a bond wire connecting the first terminal to the second terminal. 10. providing an integrated capacitor in each of the first and second floating loops to make them each resonant at the carrier frequency. 11. said connection terminal is a first connection terminal connected to a second connection terminal by the transfer conductor, the first and second connection terminals being configured for electrically connecting to a remote pair of connection terminals which in turn are electrically connected to form a floating transfer loop. 12. each of said first and second connection terminals comprises a bonding pad on a first substrate, and said remote pair of connection terminals comprises a pair of bonding pads on a second substrate.
In the drawings:
It should be understood that the drawings and corresponding detailed description do not limit the disclosure, but on the contrary, they provide the foundation for understanding all modifications, equivalents, and alternatives falling within the scope of the appended claims.
DETAILED DESCRIPTIONThe galvanically isolated signaling techniques and systems disclosed herein are best understood in context. Accordingly,
Each input and output port of the galvanic isolators 106 is preferably coupled to a module by a pair of conductors for differential signaling, though in some contemplated embodiments a ground connection may serve as one of the input or output conductors to provide single-ended signaling on that port. If both modules 102, 104 share a common ground connection, both the input and output ports may have one conductor coupled to that ground to achieve single-ended signaling on both ports. It should be evident to those skilled in the art where these variations can be applied in the ensuing examples.
A receiver 134 in module 104 receives the modulated carrier signal and demodulates it to obtain a digital receive signal 136. Though
An external transformer such as that shown in
The use of multiple galvanic isolators on the signal path (e.g., the two transformers) enables any voltage drop between the modules to be divided across the multiple transformer gaps, reducing the voltage drop across each and enabling the voltage of the floating transfer loop to migrate (via charge leakage) to an intermediate value. These properties may be advantageous for the reduced feature sizes typical of integrated transformers, but a greater attenuation may be expected due to the signal's traversal of multiple gaps.
To provide enhanced galvanic isolation with reduced attenuation and minimal complexity, the present disclosure provides for the use of coupled resonators, shown in their most basic form in
Cp=((2πfc)2Lp)−1
Similarly, the value of capacitance 204 is chosen based on, or jointly with, the self inductance of secondary 133 to provide a resonator in the second module 104 with the same resonance frequency. These resonators are electromagnetically coupled via the transformer gap 206.
For the parallel configuration, the driving impedance reaches a maximum at the resonance frequency, whereas at the resonance frequency the driving impedance reaches a minimum for the series configuration. For the series configuration, the quality factor increases as the square root of L/C. For the parallel configuration, the quality factor (at least ideally) increases as the square root of C/L. However, parasitic resistance should be considered for a proper determination of quality factor Q.
The use of coupled resonators enhances the electromagnetic coupling across the gap 206, reducing the attenuation experienced by the signal as it traverses the gap. The resonators further act as bandpass filters, passing the modulated carrier signal but strongly attenuating extraneous noise and out-of-band signals. Higher quality factors provide better filtering and more enhanced coupling, but these considerations may have to be balanced against the larger propagation delays. Resistive components may be introduced as needed to reduce the quality factors. While it may be preferred for some embodiments to employ quality factors Q in excess of 10, quality factors in the range between 1 and 10, inclusive may be suitable for most galvanically isolated signaling applications.
The pulse width modulated signal 402 is derived from digital signal 130 and in at least some contemplated embodiments represents the rising edges of the digital signal 130 with a first pulse width (e.g., 10 to 20 ns) and the falling edges with a second, different pulse width (e.g., 4 to 8 ns). The resulting modulated carrier signal produced by the oscillator 400 is thus able to convey the digital signal's polarity information across the galvanically isolated signaling path.
The floating resonator loop 312 couples with the stabilization resonator 404 to accept and convey the modulated carrier signal to the transfer loop 302. In the second module 104, the transfer loop 302 couples with another floating loop resonator 314 to convey the modulated carrier signal between the two modules 102, 104. Floating loop resonator 314 in turn electromagnetically couples to a second transfer loop 406 to convey the modulated carrier signal. Transfer loop 406 includes the primary of a step-up transformer to amplify the modulated carrier signal. The secondary of the illustrated transformer is center-tapped to ground to convert the modulated carrier signal into differential inputs for the receiver 134 while also suppressing any common mode signal. In at least one contemplated embodiment, the winding ratio of the step-up transformer is 1:8, though other winding ratios may be employed.
The center terminals of the stabilization resonator 404 are coupled to an integrated PN junction that provides the capacitive component of the resonator. The arms coupling the center terminals to the surrounding inductive element are also coupled to integrated transistors for supplying a modulated carrier signal to the stabilization resonator 404.
In the first module 102, a pair of conductor segments 500 are arranged in close parallel to provide electromagnetic coupling between the stabilization resonator 404 and the floating loop resonator 312. As both conductor segments can be included with the same metallization layer, this laterally-adjacent coupling configuration provides high a coupling coefficient with minimal manufacturing complexity. A second pair of conductor segments 501 are similarly arranged in close proximity to electromagnetically couple the floating loop resonator 312 to a transfer conductor 502 that connects two connection terminals, shown here in the form of two bonding pads. Two bond wires electrically connect the connection terminals of module 102 to two remote connection terminals of module 104. A transfer conductor 504 electrically connects together the two remote connection terminals (also shown in the form of bonding pads) to complete the transfer loop 302. A third pair of laterally-adjacent conductor segments 505 electromagnetically couples the transfer conductor 504 to the floating loop resonator 314. A fourth pair of laterally-adjacent conductor segments 506 electromagnetically couples the floating loop resonator 314 to transfer loop 406, which includes the primary for the step-up transformer. The transformer secondaries (of which only one layer is shown in
In the embodiment of
It will be appreciated by those skilled in the art that the words during, while, and when as used herein relating to circuit operation are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay(s), such as various propagation delays, between the reaction that is initiated by the initial action. Additionally, the term while means that a certain action occurs at least within some portion of a duration of the initiating action. The use of the word approximately or substantially means that a value of an element has a parameter that is expected to be close to a stated value or position. However, as is well known in the art there are always minor variances that prevent the values or positions from being exactly as stated. It is well established in the art that variances of up to at least ten percent (10%) are reasonable variances from the ideal goal of exactly as described.
The terms first, second, third and the like in the claims or/and in the Detailed Description, as used in a portion of a name of an element are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments described herein are capable of operation in other sequences than described or illustrated herein.
Reference to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but in some cases it may. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those skilled in the art. Inventive aspects may lie in less than all features of a single foregoing disclosed embodiment.
These and numerous other modifications, equivalents, and alternatives, will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such modifications, equivalents, and alternatives where applicable.
Claims
1. A system for galvanically isolated signaling, comprising:
- a first integrated circuit including: a transmitter that modulates a carrier signal having a carrier frequency to produce a modulated carrier signal on a primary conductor; a first transfer conductor connected to a first connection terminal; and a first floating loop electromagnetically coupled to the primary conductor and electromagnetically coupled to the transfer conductor to convey the modulated carrier signal from the primary conductor to the transfer conductor, wherein the first floating loop is resonant at the carrier frequency; and
- a second integrated circuit including: a second transfer conductor connected to a second connection terminal, the second connection terminal being electrically connected to the first connection terminal; a receiver that demodulates the modulated carrier signal; and a second floating loop electromagnetically coupled to the second transfer conductor and electromagnetic coupled to the receiver to convey the modulated carrier signal from the second transfer conductor to the receiver, wherein the second floating loop is resonant at the carrier frequency.
2. The system of claim 1, wherein the first floating loop shares a common metallization layer with the primary conductor and the first transfer conductor, and wherein the second floating loop shares a common metallization layer with the second transfer conductor.
3. The system of claim 1, wherein the first and second floating loops each include an integrated metal-insulator-metal plate capacitor.
4. The system of claim 1, wherein the first and second transfer conductors are part of a closed, floating transfer loop.
5. The system of claim 4, wherein the first connection terminal and the second connection terminal are coupled via a bond wire.
6. The system of claim 4, wherein the transfer loop is not resonant at the carrier frequency.
7. The system of claim 1, wherein the transmitter is configured to receive a digital signal and to responsively produce pulses in the modulated carrier signal.
8. A method for galvanically isolated signaling, comprising:
- equipping a first integrated circuit with a transmitter that modulates a carrier signal having a carrier frequency to produce a modulated carrier signal on a primary conductor;
- equipping a second integrated circuit with a receiver that demodulates the modulated carrier signal; and
- electromagnetically coupling the transmitter to the receiver using a resonantly-coupled signal path having: a first floating loop that is resonant at the carrier frequency in the first integrated circuit; a transfer loop that is not resonant at the carrier frequency; and a second floating loop that is resonant at the carrier frequency in the second integrated circuit.
9. The method of claim 8, wherein the transfer loop includes a first transfer conductor in the first integrated circuit, the first transfer conductor sharing a common metallization layer with the first floating loop, and wherein the transfer loop includes a second transfer conductor in the second integrated circuit, the second transfer conductor sharing a common metallization layer with the second floating loop.
10. The method of claim 9, wherein the transfer loop further includes a first terminal connected to the first transfer conductor, a second terminal connected to the second transfer conductor, and a bond wire connecting the first terminal to the second terminal.
11. The method of claim 8, further comprising providing an integrated capacitor in each of the first and second floating loops to make them each resonant at the carrier frequency.
12. The method of claim 11, wherein the integrated capacitors are each metal-insulator-metal plate capacitors.
13. The method of claim 8, wherein the transmitter is configured to receive a digital signal and to responsively produce pulses in the modulated carrier signal.
14. An integrated circuit for galvanically isolated signaling via a connection terminal, the integrated circuit comprising:
- a transfer conductor connected to the connection terminal;
- a transmitter that modulates a carrier signal having a carrier frequency to produce a modulated carrier signal; and
- a floating loop electromagnetically coupled to the transmitter and to the transfer conductor to convey the modulated carrier signal from the transmitter to the transfer conductor,
- wherein the floating loop is resonant at the carrier frequency.
15. The integrated circuit of claim 14, wherein said connection terminal is a first connection terminal connected to a second connection terminal by the transfer conductor, the first and second connection terminals being configured for electrically connecting to a remote pair of connection terminals which in turn are electrically connected to form a floating transfer loop.
16. The integrated circuit of claim 15, wherein the floating transfer loop is not resonant at the carrier frequency, and wherein the floating loop is configured to resonantly couple with a second floating loop via the transfer conductor, the second floating loop being resonant at the carrier frequency.
17. The integrated circuit of claim 15, wherein each of said first and second connection terminals comprises a bonding pad on a first substrate, and wherein said remote pair of connection terminals comprises a pair of bonding pads on a second substrate.
18. The integrated circuit of claim 14, wherein the transmitter is configured to receive a digital signal and to responsively produce pulses in the modulated carrier signal.
19. The integrated circuit of claim 14, wherein the floating loop includes an integrated metal-insulator-metal plate capacitor.
Type: Application
Filed: Apr 19, 2018
Publication Date: Aug 23, 2018
Applicant: SEMICONDUCTOR COMPONENTS INDUSTRIES, LLC (Phoenix, AZ)
Inventors: Richard Scott BURTON (Phoenix, AZ), Karel PTACEK (Roznov pod Radhostem)
Application Number: 15/957,153