Patent Grant
9805693
One or more aspects of embodiments according to the present invention relate to data transmission, and more particularly to a system for combining multiple reverse data streams into one, in a display device.
Display devices may be constructed with a timing controller (TCON) that sends high rate (e.g., video) data to driver integrated circuits (DICs) on source boards at the display panel. In addition to the video data sent in the “forward” direction, reverse data may also be sent by the DICs to the TCON. Such reverse data may carry information, for example, from sensors (e.g., touch sensors or optical sensors) embedded in the display panel. The data rate of the reverse data may be lower than (e.g., 1/10th) that of the forward data.
The use of the individual forward links as bi-directional links, e.g., in a full-duplex or half-duplex system, may result in near end crosstalk (NEXT) for the forward link and vice versa. The use of dedicated reverse lanes (one per DIC) may result in a need to add traces, connectors, and cables to the system, and may consequently increase cost. The additional of a chip to the source board that aggregates the data from all low-speed reverse links and sends the aggregated data back to the TCON at high speed may also increase cost, and complexity.
Thus, there is a need for a cost-effective system for transmitting reverse data from a plurality of DICs to a TCON.
According to an embodiment of the present invention there is provided a plurality of bidirectional display driver integrated circuits (DICs) connected in a chain, the chain having a beginning and an end, each of the plurality of DICs including: a direct data input; a relay data input; and a relay data output, each of the plurality of DICs being configured: to combine data received at the direct data input with a stream of bits received at the relay data input to form combined data, and to transmit the combined data through the relay data output.
In one embodiment, a first DIC of the plurality of DICs is at the beginning of the chain, and the relay data input of the first DIC is wired to receive a stream of bits at a first logic level.
In one embodiment, a first DIC of the plurality of DICs is configured to transmit, at the relay data output of the first DIC, a stream of data words, each data word having n bits, n being the number of DICs in the chain.
In one embodiment, the transmitting includes: for a first bit of each data word, retransmitting a bit received at the direct data input of the DIC; and for the remaining n−1 bits of each data word, retransmitting n−1 corresponding bits received at the relay data input of the DIC.
In one embodiment, the position within each data word of the first bit corresponds to a position of the first DIC within the chain.
In one embodiment, each of the plurality of DICs further includes a forward data input.
In one embodiment, each of the plurality of DICs further includes a reverse data clock and each of the plurality of DICs is configured to synchronize the reverse data clock of the DIC to a clock signal embedded in a forward data signal received at the forward data input of the DIC.
In one embodiment, each of the plurality of DICs is configured, at power-up, to: wait, when the stream of bits received at the relay data input is a stream of bits at a first logic level.
In one embodiment, the first logic level is logical one.
In one embodiment, each of the plurality of DICs is configured, at power-up, to: transmit a stream of data words, each data word having n bits, n being the number of DICs in the chain, a first bit of each data word being at a second logic level, and the remaining n−1 bits of each data word being at a third logic level, different from the second logic level, when the stream of bits received at the relay data input is a stream of bits at a fourth logic level, different from the first logic level.
In one embodiment, each of the plurality of DICs is configured, after waiting while the stream of bits received at the relay data input is a stream of bits at a first logic level and after the stream of bits received at the relay data input ceases to be a stream of bits at the first logic level, to: transmit, at the relay data output of the DIC, a stream of data words, n−1 bits of each data word being equal to corresponding bits received at the relay data input, and the remaining one bit of each data word being set to a second logic level different from the first logic level.
In one embodiment, the position within each data word of the one bit corresponds to a first bit position in the stream of bits received at the relay data input, the first bit position being adjacent to a transition in the stream of bits received at the relay data input.
In one embodiment, the second logic level is logical zero.
In one embodiment, all of the DICs are identical.
In one embodiment, the relay data input of each of the plurality of DICs is a serial data input.
In one embodiment, the relay data output of each of the plurality of DICs is a serial data output.
According to an embodiment of the present invention there is provided a display including: a display panel including a plurality of sensors; a timing controller (TCON); and a plurality of bidirectional display driver integrated circuits (DICs) connected in a chain, the chain having a beginning and an end, each of the plurality of DICs including: a direct data input connected to one of the plurality of sensors; a relay data input; and a relay data output, the relay data output of one of the plurality of DICs being connected to the TCON, each of the plurality of DICs being configured: to combine data received at the direct data input with a stream of bits received at the relay data input to form combined data, and to transmit the combined data through the relay data output.
In one embodiment, a first DIC of the plurality of DICs is configured to transmit, at the relay data output of the first DIC, a stream of data words, each data word having n bits, n being the number of DICs in the chain.
In one embodiment, the transmitting includes: for a first bit of each data word, retransmitting a bit received at direct data input of the DIC; and for the remaining n−1 bits of each data word, retransmitting n−1 corresponding bits received at the relay data input of the DIC.
According to an embodiment of the present invention there is provided a display including a timing controller (TCON) and a plurality of driver integrated circuits (DICs), each of the plurality of DICs including: a direct data input; a relay data input; a relay data output; and means for: combining data received at the direct data input with a stream of bits received at the relay data input to form combined data, and transmitting the combined data through the relay data output.
These and other features and advantages of the present invention will be appreciated and understood with reference to the specification, claims, and appended drawings wherein:
The detailed description set forth below in connection with the appended drawings is intended as a description of exemplary embodiments of a relay-based bidirectional display interface provided in accordance with the present invention and is not intended to represent the only forms in which the present invention may be constructed or utilized. The description sets forth the features of the present invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and structures may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention. As denoted elsewhere herein, like element numbers are intended to indicate like elements or features.
Referring to
In each relay chain, the first DIC in the relay chain (i.e., the DIC at the beginning of the chain) re-transmits the data it receives from the display panel to the next DIC in the relay chain. The second DIC in the chain then interleaves the data it receives from the display panel with the data it receives from the first DIC, and transmits the combined data stream to the third DIC in the chain. Similarly, every subsequent DIC in the chain interleaves the data it receives from the display panel with the data it receives from the preceding DIC in the chain, and transmits the combined data stream to the next DIC in the chain, or (if it is the last DIC in the chain, i.e., the DIC at the end of the relay chain), to the TCON. The reverse data received by a DIC directly from the display panel are referred to herein as “direct data”, and the data each DIC (except the first DIC) receives from the DIC preceding it in the chain are referred to herein as “relay data”.
For example, the four DICs numbered 1 through 4 in
In one embodiment, illustrated in
In the embodiment of
As one of skill in the art will understand, the numbers and ratios shown in
Referring to
In each DIC, the reverse data clock may be used to clock the transmitted data, in a reverse link transmitter (RL TX) 330. As the reverse data clocks in the DICs are all at the same frequency (since all forward links are connected to the same TCON), all the reverse link transmitters 330 in the display system are also at the same frequency, although they may be at different phases. For the Nth DIC (which may be referred to as DIC(N)), the reverse link serial signal received from the (N−1)th DIC (which may be referred to as DIC(N−1)), is on the reverse data clock domain of DIC(N−1) plus a channel flight-time delay. To properly receive these data at DIC(N), the phase of the local reverse clock of DIC(N) may be calibrated, for example using a phase interpolator (PI) 335 and a phase calibration (PCAL) state-machine 340, so that the reverse link receiver (RL RX) 345 samples the incoming relay data at the center of the received eye. The sampled relay data then are passed to the internal reverse data clock (i.e., PHY clock) domain of the reverse data clock of DIC(N) where the data are time-multiplexed (e.g., interleaved) with the direct data received from the display panel (or “Data from DRV”) and subsequently re-transmitted through reverse link transmitter port.
In the embodiment of
Referring to
When the RL RX input of DIC2 changes from a stream of ones to a stream in which the pattern “1 1 1 0” repeats, the relay input of DIC2 undergoes two transitions (from low to high and then from high to low) per relay data word. DIC2 may then perform a phase calibration, under the control of the phase calibration (PCAL) state-machine, using one or both of the received transitions as a phase reference. For example, the phase calibration state-machine may gradually change the phase of the relay data receiver sampler 520 until the received data stream has one more or one fewer 1 (e.g., a pattern of “0 1 1 1 1 0” “0 1 1 0” is received) and then adjust the phase back by one-half cycle so that the sampling point is centered in the eye of the received relay data. In another embodiment, a clock and data recovery circuit which includes a crossing slicer (or “sampler” or “clocked comparator”) that samples the received relay data 90 degrees out of phase with the data sampler, and provides continuous phase feedback control, may be used. In yet another embodiment, all of the DICs may be programmed to transmit alternating ones and zeros (i.e., a half-rate clock) for some period of time after startup, and each DIC in the chain, except the first, may perform a phase calibration during this period. Once the phase calibration time has elapsed, each DIC may begin transmitting a stream of ones until the remainder of the initialization sequence is complete.
When DIC1 transmits (and DIC2 receives) the pattern “1 1 1 0”, this indicates to DIC2 (i) that the preceding DIC in the chain has completed its initialization, and (ii) where in the relay word its allocated bit position is. In the example of
Because the time of flight of the signal between DICs may not be an integer multiple of the relay data clock period, the circuit within each DIC may operate in two clock domains, one being a clock with a phase adjusted to receive the relay data from the preceding DIC in the relay chain, and the other being the local reverse data clock formed from the forward data clock embedded in the forward data. If the relay data clock is formed by dividing the forward data clock by an integer, then it may be synchronized in phase to the forward data clock. The clock domains may be bridged, for example, by a depth-one first-in-first-out (FIFO) circuit.
Referring to
The initialization block 545 receives the received relay data stream. When it detects a pattern including one or more zeros (i.e., the DIC is no longer receiving a stream of ones because the preceding DIC has completed its initialization), it identifies the slot allocated to the DIC being initialized, it initializes a circular shift register 550 with a one, and, e.g., 3 zeros (as illustrated in
Once the circular shift register 550 is initialized, and for the remainder of the initialization time period, the DIC transmits a zero in its allocated bit position (this functionality is not shown in
Referring to
If the DIC determines, in act 615, that is not receiving a stream of zeros, then it determines, in an act 625 whether it is receiving a stream of ones, and if so, it waits, in an act 630 as long as this condition continues (i.e., while the preceding DIC completes its initialization). Once it is no longer receiving a stream of ones, it determines, in an act 635, whether its phase calibration (which begins as soon as transitions are received at RL RX) is complete, and waits, in an act 640, until its phase calibration is complete. It then finds, in an act 645, the “10” transition in the received relay data, remembers (e.g., by suitable initialization of the circular shift register 550) the location of the one (of the bit pair “10”), replaces it with zero in the pattern, and retransmits the modified pattern at its RL TX output.
Each DIC may start a timer at power-up, and, after a suitable amount of time has elapsed, insuring that all DICs in the chain have had time to complete the initialization process, it may begin transmitting relay data.
As one of skill in the art will understand, certain aspects of implementation may be changed from those of the exemplary embodiments described herein, without changing the principle of operation of embodiments of the present invention. For example, the bit values of zero and one may be reversed in various combinations. For example, the relay data input of DIC1 may be hard-wired to one instead of to zero, and DIC1 may, after detecting that it is receiving a stream of ones, begin transmitting the pattern “0 0 0 1” instead of “1 1 1 0”. As another example, each DIC in the chain after the first DIC need not allocate to itself a bit position immediately adjacent to a bit position allocated to the preceding DIC in the chain, but may allocate to itself any bit position not already allocated to a DIC.
Each DIC may be configured by one or more of various methods with information about the system. Such information be hard-wired in the chip (i.e., made part of the permanent wiring of the chip at fabrication), stored in firmware (e.g., in nonvolatile write-once or re-writable memory on the chip), stored in volatile memory (e.g., written to one or more registers in the DIC after power-up), hard-wired into a printed circuit board onto which the chip is installed, or discovered by the DIC after power-up during initialization. For example, as described, each DIC may discover its position in the relay chain during initialization. As another example, wiring on a printed circuit board may, as described above, identify the first DIC in the relay chain. Similarly, each DIC may be configured by one of the above methods with information about the number of DICs in the chain (which the DIC may discover from the length of the bit sequence it receives during initialization). The ratio of the forward data clock to the reverse data clock may be programmed into one or more registers in the DIC, or hard-wired in the DIC.
In the configuration of
In another embodiment illustrated in
Embodiments of the present invention have various features and benefits. In some embodiments, since the clocks of all DICs are frequency locked to the TCON clock (i.e., the forward data clock) through the forward link, no frequency acquisition may be necessary for the reverse link. Only phase acquisition may be performed, through a phase calibration (PCAL) algorithm, utilizing a phase-interpolator and a state machine to center the reverse link receiver data eye with respect to the DIC clock derived from the forward link, which is in turn derived from the TCON clock.
In some embodiments all DIC-to-DIC reverse links are short and point-to-point, and the RL RX can be a simple and low-power receiver. As mentioned above, a simple circular shift register that circulates a “1” level can be used to multiplex between relay data from RL RX and direct data from DRV. As a result of the data relay, the final DIC in the chain (e.g., DIC4) is physically closer to the TCON, and the reverse relay data rate may be R/2 (or lower depending on the embodiment and the desired reverse data rate per DIC). Therefore, the signal quality in the reverse link may be higher between the final DIC in the chain and the TCON (than the signal quality, for example, in the forward link), leading to simpler circuit designs compared to the forward link. In some embodiments, the RL TX is designed using voltage-mode drivers so that it only consumes power during data transitions, lowering the system power consumption compared to other approaches.
It will be understood that, although the terms “first”, “second”, “third”, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section, without departing from the spirit and scope of the inventive concept.
Spatially relative terms, such as “beneath”, “below”, “lower”, “under”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that such spatially relative terms are intended to encompass different orientations of the device in use or in operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” or “under” other elements or features would then be oriented “above” the other elements or features. Thus, the example terms “below” and “under” can encompass both an orientation of above and below. The device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should be interpreted accordingly. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the inventive concept. As used herein, the terms “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. As used herein, the term “major component” means a component constituting at least half, by weight, of a composition, and the term “major portion”, when applied to a plurality of items, means at least half of the items.
As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising”, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. Further, the use of “may” when describing embodiments of the inventive concept refers to “one or more embodiments of the present invention”. Also, the term “exemplary” is intended to refer to an example or illustration. As used herein, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively.
It will be understood that when an element or layer is referred to as being “on”, “connected to”, “coupled to”, or “adjacent to” another element or layer, it may be directly on, connected to, coupled to, or adjacent to the other element or layer, or one or more intervening elements or layers may be present. In contrast, when an element or layer is referred to as being “directly on”, “directly connected to”, “directly coupled to”, or “immediately adjacent to” another element or layer, there are no intervening elements or layers present.
The electronic or electric devices and/or any other relevant devices or components of a display according to embodiments of the present invention described herein may be implemented utilizing any suitable hardware, firmware (e.g. an application-specific integrated circuit), software, or a combination of software, firmware, and hardware. For example, the various components of these devices may be formed on one integrated circuit (IC) chip or on separate IC chips. Further, the various components of these devices may be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or formed on one substrate. Further, the various components of these devices may be a process or thread, running on one or more processors, in one or more computing devices, executing computer program instructions and interacting with other system components for performing the various functionalities described herein. The computer program instructions are stored in a memory which may be implemented in a computing device using a standard memory device, such as, for example, a random access memory (RAM). The computer program instructions may also be stored in other non-transitory computer readable media such as, for example, a CD-ROM, flash drive, or the like. Also, a person of skill in the art should recognize that the functionality of various computing devices may be combined or integrated into a single computing device, or the functionality of a particular computing device may be distributed across one or more other computing devices without departing from the spirit and scope of the exemplary embodiments of the present invention.
Although exemplary embodiments of a relay-based bidirectional display interface have been specifically described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. Accordingly, it is to be understood that a relay-based bidirectional display interface constructed according to principles of this invention may be embodied other than as specifically described herein. The invention is also defined in the following, claims, and equivalents thereof.
The present application claims priority to and the benefit of U.S. Provisional Application No. 62/087,770, filed Dec. 4, 2014, entitled “A RELAY-BASED BIDIRECTIONAL DISPLAY INTERFACE”, the entire content of which is incorporated herein by reference.
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