TW201301820A - Communicating with a self-clocking amplitude modulated signal - Google Patents

Abstract

Examples disclosed herein provide for a method for transmitting a signal. The method includes generating a Manchester encoded data stream and combining the Manchester encoded data stream with an amplified clock signal to produce an amplitude modulated signal having a zero crossing at each edge of the amplified clock signal. The amplitude modulated signal can then be sent over a communication medium.

Description

Communication with self-timed amplitude modulation signal

The present invention relates generally to signal transmission, and in particular to the transmission of clock signals in combination with digital data signals.

Cross-reference to related applications

This application is a sequel to the continuation of U.S. Patent Application Serial No. 12/775,517, entitled "CAPACITIVE DIVIDER TRANSMISSION SCHEME FOR IMPROVED COMMUNICATIONS ISOLATION", which is filed on May 7, 2010, which is hereby incorporated herein by reference. The right of U.S. Provisional Patent Application No. 61/176,800 (hereinafter referred to as "the '800 Application"), entitled "A ROBUST 2-WIRE DAISY CHAIN COMMUNICATION SYSTEM", filed on May 8, 2009. The present application is also related to U.S. Provisional Patent Application Serial No. 61/498,984, entitled "AMPLITUDE ADJUSTED PULSE FOR DC BALANCED SIGNAL WITH TRANSFORMER COUPLING", filed on June 20, 2011 (hereinafter referred to as "984 Application"). This application claims the priority rights of the '517 application, the '800 application, and the `984 application. The '517 application, the '800 application, and the '984 application are hereby incorporated herein by reference.

Transmitters have been developed for transmitting combined clock signals and digital data signals. However, the combined signal has been modulated on the carrier. Although this is specific The situation is beneficial, but adds extra complexity to the circuit.

In an example, a method for transmitting a signal is provided. The method includes generating a Manchester encoded data stream and combining the Manchester encoded data stream with an amplified clock signal to produce an amplitude modulated signal having a zero crossing on each edge of the amplified clock signal. The amplitude modulation signal is then transmitted via the communication medium.

In the following detailed description, reference to the accompanying drawings The embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that other embodiments may be utilized, and logical, mechanical, and electrical changes can be made without departing from the scope of the invention. Therefore, the following detailed description is not intended to be limiting.

High voltage systems typically require communication solutions that provide voltage isolation and robust performance in the presence of electromagnetic interference (EMI) and power transients. These solutions are further improved by limiting EMI transmission. Embodiments described herein provide transmission systems and solutions that have high transient and EMI immunity due to low EMI emissions.

FIG. 1A is a schematic diagram of an embodiment of a communication system 100 having capacitive coupling. Communication system 100 includes a first transceiver 102 coupled to a second transceiver 104 via communication medium 106. Communication medium 106 is used as the first transceiver A transmission line between 102 and the second transceiver 104. Embodiments of communication medium 106 include wired links such as cables (e.g., flexible flat cables), circuit board traces, twisted pairs, or other communication media. Communication between the first transceiver 102 and the second transceiver 104 is bidirectional on the shared communication medium 106. The connection of communication medium 106 to first and second transceivers 102 and 104 can be accomplished with any suitable connection now known or later developed.

The first transceiver 102 has a receive function including a communication pin input clamp 107, a trigger driver 133 coupled to the input of the differential driver 132, wherein the two feedback resistors 131-1 and 131-2 are coupled to the difference The output of the drive 132. The first transceiver 102 also includes a transmission driver 134. Symmetrically, the second transceiver 104 has a receive functionality that includes a trigger driver 136 coupled to an input of the differential driver 135, wherein the two feedback resistors 137-1 and 137-2 are coupled to the differential driver 135 Output; and transport functionality, including transport driver 138. The resistors described herein can be any suitable resistive element.

Communication system 100 is discussed further herein with respect to blocks A, B, and C. Each block includes circuitry configured to perform one or more functions. As will be described, blocks A and C provide terminal load for block B, and block B reacts to provide voltage division and voltage isolation. Blocks A and C can provide low impedance load conditions that allow signals to be transmitted while reducing EMI effects. In one example, the first transceiver 102 includes a first port 120-1 and a second port 120-2 to communicate with a second transceiver 104 having a third port 120-3 and a fourth port 120-4. The first and second transceivers 102 and 104 can be coupled together via two paths called high path 139-1 and low path 139-2. High road The path 139-1 may include from the 埠 120-1 of the first transceiver 102 through the block A, the one or more first wires of the communication medium 106, the blocks B and C to the 埠 120-3 of the second transceiver 104. Signal path. The low path 139-2 may include 埠 120-4 from the 埠 120-2 of the first transceiver 102 through block A, one or more first wires of the communication medium 106, blocks B and C to the second transceiver 104. Signal path. In an example, the transceivers 102, 104 can transmit differential signals via the high path 139-1 and the low path 139-2.

As shown generally by block A, the first transceiver 102 can be coupled to the communication medium 106 via resistors 113-1 and 113-2 and capacitors 114-1 and 114-2 for paths 139-1 and 139-2, respectively. Capacitors 114-1 and 114-2 are each connected to ground. Differential capacitor 112 can be placed between resistors 113-1 and 113-2 and communication medium 106 across paths 139-1 and 139-2. In one embodiment, transceiver 102 and block A are co-located on a single wafer. In one embodiment, one or both of transceivers 102 and 104 are quadrature amplitude modulation (QAM) transceivers.

A differential capacitor 112 can be coupled between paths 139-1 and 139-2 to provide a differential capacitive termination and can reduce the tolerance effects of capacitors 114-1 and 114-2. Capacitors 114-1 and 114-2 are differential termination capacitors that provide protection against transients by forming a discharge path to ground. When the communication system 100 is exposed to EMI having a frequency higher than the data communication rate, the EMI effect on the receiver side can be reduced due to the low impedance on the paths 139-1 and 139-2 where the differential capacitor 112 is present. In addition, the low impedance and high frequency on the receiver can work together to eliminate EMI. The differential capacitor 112 can reduce the tolerance effect of the grounded connected capacitors 114-1 and 114-2.

As shown generally by block C (symmetric with block A), the second transceiver 104 can be coupled to via resistors 123-1 and 123-2 and capacitors 124-1 and 124-2 for paths 139-1 and 139-2, respectively. Communication medium 106. Capacitors 124-1 and 124-2 can be connected to ground. Differential capacitor 122 can be coupled between paths 139-1 and 139-2 and positioned between resistors 123-1 and 123-2 and resistors 119-1 and 119-2. The capacitor in block C operates in a manner similar to the capacitor in block A.

The second transceiver 104 can be coupled to the communication medium 106 via the transformer 118 as shown generally by the isolation block B. Transformer 118 can provide voltage isolation for second transceiver 104. In some examples, a resistor circuit can be used to convert a current source into a voltage signal and provide signal attenuation as a voltage divider. For example, a resistor divider circuit can be used to define the signal on the second transceiver 104 and attenuate the signal. This voltage division can be used to scale the voltage across the receiver to allow compatibility with receiver characteristics. The resistors in blocks A and C also increase the level of protection against transient events by limiting the current of the signal through communication medium 106.

In an example, the resistor divider circuit can include a series resistor on each side of the transformer 118 for each of the communication paths 139-1, 139-2. Thus, in the example shown in FIG. 1A, first resistor 119-1 can be coupled in series between high path 139-1 and transformer 118. The second resistor 119-2 can be coupled in series between the path 139-2 and the transformer 118. The third resistor 119-3 can be coupled in series between the third turn 120-3 of the second transceiver 104 and the transformer 118. The fourth resistor 119-4 can be coupled in series between the fourth turn 120-4 of the second transceiver 104 and the transformer 118.

The resistor divider circuit can also include a resistor coupled between communication paths 139-1, 139-2 on either side of transformer 118. Thus, in the example shown in FIG. 1A, a fifth resistor 119-5 is coupled between the high path 139-1 and the low path 139-2. This fifth resistor 119-5 is coupled in circuit between the communication medium 106 and the transformer 118. A sixth resistor 119-6 can also be coupled between the high path 139-1 and the low path 139-2. However, this sixth resistor can be coupled in circuit between the transformer 118 and the third and fourth turns 120-3, 120-4 of the second transceiver 104. Resistors 119-1, 119-2, 119-3, 119-4, 119-5, and 119-6 can be used to provide voltage division as described above for signal attenuation. In one embodiment, transceiver 104 and blocks B and C are located together on a single wafer.

FIG. 1B is a schematic diagram of another embodiment of a communication system 170 having transformer coupling. Communication system 170 can include many components similar to communication system 100 described with respect to FIG. 1A. Similar components have been marked with the same symbol. Communication system 170 can include a first transceiver 102 and a second transceiver 104 communicatively coupled to communication medium 106. Communication system 170 can also include a plurality of blocks D, E, F, G coupled between transceivers 102, 104. Each block D, E, F, and G includes circuitry configured to perform one or more functions.

Blocks D and E provide low impedance load conditions that allow signal transmission while reducing EMI effects. Blocks D and E in system 170 may be similar to blocks A and C described with respect to FIG. 1A, except that blocks D and E do not include optional series resistors 113-1, 113-2, and 123-1, 123 of FIG. 1A. Outside of -2. However, capacitors 112, 114-1, 114-2, 122, 124-1, and 124-2 are similar The manner described with respect to blocks A and C in Fig. 1A functions.

Communication system 170 may include one or more isolation blocks F and G to provide isolation for transceivers 102, 104. The isolation block F can be located between the terminal block D and the communication medium 106. The isolation block F can include a transformer 121 coupled between the first and second ports 120-1, 120-2 and the communication medium 106 to provide voltage isolation (e.g., isolation boundaries) for the first transceiver 102. Resistors 119-1, 119-2, and 119-5 may be located between first and second turns 120-1, 120-2 of first transceiver 102 and transformer 121 of isolation block F. With this positioning, resistors 119-1, 119-2, and 119-5 can be coupled in communication paths 139-1, 139-2 in the same manner as described in block C in circuit 100. Thus, the first resistor 119-1 can be coupled in series between the first 埠 120-1 of the transceiver 102 and the transformer 121 of the isolation block F. The second resistor 119-2 can be coupled in series between the second turn 120-2 of the transceiver 102 and the transformer 121 of the isolation block F. A fifth resistor 119-5 can be coupled between the high path 139-1 and the low path 139-2. In this example, a fifth resistor 119-5 can be coupled in the electrical circuit between the first and second turns 120-1, 120-2 of the transceiver 102 and the transformer 121 of the isolation block F. Thus, the isolation block F can provide functionality similar to the isolation block B of Figure 1A.

In some examples, an isolation block can be included on each end of the communication medium 106 to provide protection to a user who may be in contact with the communication medium 106 when the communication medium 106 is disconnected from one of the transceivers 102, 104. For example, this may occur during installation or maintenance of communication system 100. FIG. 1B illustrates such circuitry including two isolation blocks F and G, with one isolation block on each transceiver 102, 104. As shown, the isolation block G Can be a mirror image of the isolation block F. Accordingly, the isolation block G can include a transformer 118 coupled between the third and fourth ports 120-3, 120-4 and the communication medium 106 to provide voltage isolation (eg, an isolation boundary) for the second transceiver 104. The isolation block G can include resistors 119-3, 119-4, and 119-6, which can be located at the third and fourth ports 120-3, 120-4 of the second transceiver 104 and the transformer 118 of the isolation block G. between. Resistors 119-3, 119-4, and 119-6 can be coupled in communication paths 139-1, 139-2 in the same manner as described with respect to block C in circuit 100. Thus, resistor 119-3 can be coupled in series between third turn 120-3 of transceiver 104 and transformer 118 of isolation block G. Resistor 119-4 can be coupled in series between fourth turn 120-4 of transceiver 104 and transformer 118 of isolation block G. Resistor 119-6 can be coupled between high path 139-1 and low path 139-2. In this example, resistor 119-6 can be coupled in circuit between third and fourth turns 120-3, 120-4 of transceiver 104 and transformer 118 of isolation block G, thus, isolation block G can provide Similar to the function of the isolation block F.

The functionality of the communication systems 100, 170 is described below with respect to one-way communication aspects, but it should be appreciated that the systems 100 and 170 can provide two-way communication. The first transceiver 102 (acting as a transmitter) can transmit signals to the second transceiver 104 (acting as a receiver). Although the first transceiver 102 is transmitting, the capacitors and resistors in blocks A and D, respectively, can control the edge rate of the signal (ie, the rise time of the signal). In an embodiment, the transmitted signal may be modified by the switched current source described below in FIG. 4 in transceiver 102 such that capacitors 112, 114-1, and 114-2 receive the ramp signal. The EMI transmission frequency from this signal is determined by the rise time of the ramp, where the transmission signal is increased The frequency of the number increases the power of the EMI. Thus, the power in communication systems 100 and 170 can be determined by the edge frequency. As the signal rise time transmitted by transceiver 102 is reduced, the frequency of the signal transmitted via communication medium 106 is also reduced. The potential EMI can be reduced due to the separate differential structure of the communication systems 100, 170 and the coupling of the transceiver 102 to the communication medium 106. Blocks C and E can affect the signals transmitted from the second transceiver 104 in a manner similar to how blocks A and D affect the signals transmitted from the first transmitter 102, respectively.

The optional resistors 113-1 and 113-2 shown in FIG. 1A can improve the elimination of very high frequency (VHF) EMI and the pin input capacitance of the transceivers 102 and 104. Some embodiments of communication system 100 including a current source derived transmission scheme may not include resistors 113-1 and 113-2.

Examples of values of components in blocks A, B, C, D, E, and F are described herein to illustrate signal levels commensurate with a particular current source value relationship. It should be noted that this example is merely illustrative and that the capacitance, resistance, and inductance can be any suitable value.

1C is a block diagram of an embodiment of a daisy chain system 140 utilizing the communication system 100 of FIG. 1A, the communication system 170 of FIG. 1B, or both. System 140 includes N devices 142-1 through 142-N communicatively coupled together in a daisy chain using a plurality of communication systems 100, 170. Apparatus 142-1 is communicatively coupled to first transceiver 150-1, first transceiver 150-1 is coupled to communication medium 106-1, communication medium 106-1 is coupled to second transceiver 150-2, second transceiver 150-2 is then coupled to device 142-2. The first transceiver 150-1, the communication medium 106-1, and the second transceiver 150-2 form a communication system 100 or communication system 170 and are thus coupled together as shown in FIG. 1A or FIG. 1B. The second device 142-2 can then provide a clock signal and a data signal to the third transceiver 150-3 for transmission down the daisy chain to one or more devices 142-N. The third transceiver 150-3 is coupled to the communication medium 106-2. The other device 142-N can receive signals from the device along the daisy chain via the transceiver 150-M coupled to the communication medium 106-(N-1). As such, the transceiver 150-M utilizes the communication medium 106-N to link the device 142-N to the daisy chain system 140. Each transceiver 150-1 to 150-N may have at least two transmission/reception ports (e.g., 120-1, 120-2). Further, circuits corresponding to blocks A-G of FIGS. 1A and 1B may be included between respective transceivers 150-1 to 150-N.

In an embodiment, the daisy chain system 140 can function as follows. The timing of the daisy chain system 140 is controlled by the system clock 152. Device 142-1 provides a clock (CLK) signal and data signal from system clock 152 to transceiver 150-1. The transceiver 150-1 can combine the data signal and the pulse signal to form A mixed coded data signal (also referred to herein as a daisy chain signal). The hybrid coded data signal is an amplitude modulated square wave signal and can be formed, for example, according to the Manchester coding scheme discussed below. This hybrid encoded data signal can be transmitted to transceiver 150-2 via communication medium 106-1. Operating in the receive mode, the transceiver 150-2 can receive the hybrid encoded data signal, decode the signal to extract the data signal and the pulse signal. Transceiver 150-2 can then provide a data signal to the device 142-2.

This process can be repeated similarly throughout the daisy chain system 140. For example, after the data signal and the pulse signal are provided to the device 142-2, the device 142-2 can provide the clock signal and its own data signal to the transceiver 150-3 for transmission down the daisy chain to the device 142-N. . Transceiver 150-3 can be coupled to communication medium 106-2 and transceiver 150-3 can combine the data signal from device 142-2 with the extracted clock signal from transceiver 150-2 to form a second hybrid Encoded data signals. This second hybrid encoded data signal can be transmitted down the daisy chain to the transceiver 150-M. The transceiver 150-M can receive the mixed encoded data signal and decode the signal to extract the data signal and the pulse signal. The transceiver 150-M can then provide a data signal to the device 142-N. Thus, the daisy-chain transceivers 150-2 through 150-N can provide the extracted clock signals from the system clock 152 to the devices 142-2 through 142-N.

As such, as shown in FIG. 1C, one or more of the communication systems 100, 170 can be chained together in a daisy chain. The daisy chain signal can provide information such as register contents, device commands, and read or write scratchpad contents from one device 142-1, 142-2, 142-3, 142-N to another device, for example. .

In an embodiment, the transceiver 150-1 can be packaged onto a single wafer, single crystal The sheets can be mounted to the board along with appropriate circuitry corresponding to blocks A-G. The board can then be connected to a device such as device 142-1. In an embodiment, the daisy chain system 140 can be used to daisy-chain a plurality of devices 142-1, 142-2, 142-N to a plurality of battery cells. The daisy chain system 142 can be a module that enters the battery pack. In an embodiment, the battery unit is a lithium ion (Li ion) battery unit. In another embodiment, 12 Li-ion battery cells are connected by communication systems 100, 170 to protect the robust module from transient events and EMI.

2A is a block diagram of an embodiment of a transceiver 200 that includes a transmitter 210 and a receiver 230. The transmitter 210 includes a DC balanced data encoder 212, a multiplier 214, and a summer 216. The transmitter 210 receives the data signal and the pulse signal from the device, for example, via the communication medium 106, encodes the data, combines the encoded data with the amplified clock signal, and transmits the data. Receiver 230 receives the hybrid encoded data signal, for example, via communication medium 106, decodes the data signal, and extracts the clock signal.

An embodiment of DC balanced data encoder 212 employs Manchester encoding; however, DC balanced data encoder 212 may utilize any other encoding scheme for DC balanced data. The Manchester coding system provides a basic coding scheme for two clock cycles for each data bit, for a 50% efficiency level. In other words, every two edges of the Manchester encoded data stream produce one bit of data.

In one embodiment, a data (DATA) signal with a similar amplitude (CLK) signal is encoded in the DC balanced data encoder 212. CLK signal and DATA signal are combined into an amplitude-modulated Manchester coding scheme Timing coded signal. Therefore, the clock signal can be easily recovered from the Manchester encoded data without the need for a phase locked loop (PLL) because the CLK signal is embedded in the timing encoded signal. Furthermore, since the PLL is not necessary, the training sequence for triggering the PLL does not have to be added to the output of the DC balanced data encoder 212. Therefore, since the timing coded signal does not need to be locked to the clock, each bit of the DATA signal can be recovered without delay.

Using multiplier 214, the amplitude of the clock signal is multiplied by a factor, such as two. Summer 216 sums the time-coded signal and the multiplied CLK signal (the signals are the outputs of DC balance data encoder 212 and multiplier 214, respectively) and produces a total output that is transmitted to receiver 230.

Receiver 230 includes a zero crossing detector 232 and a summer 236, both coupled directly to transmitter 210, multiplier 234, and data decoder 238. Zero crossing detector 232 receives the transmitted encoded signal and recovers the CLK signal at its output terminal. The output of zero crossing detector 232 is multiplied by multiplier 234 and supplied to the first input terminal of summer 236. Summer 236 receives the transmitted signal on its second input terminal. Data decoder 238 receives the output of summer 236 and the clock signal recovered by zero crossing detector 232 to recover the data. The signal shown at point A has a similar amplitude.

2B is a block diagram of an embodiment of a transceiver 250 that includes a transmitter 260 and a receiver 270. Transmitter 260 is similar to transmitter 210 except that transmitter 260 uses XOR gate 262 in place of DC balance and data encoder 212. Similarly, receiver 270 is similar to receiver 220 except that receiver 270 uses XOR gate 278 instead of data decoder 278. The encoded signal is mixed with a Manchester encoded signal (generated by XOR gate 262). Produced by providing a mixed coded signal. The hybrid coded signal has an amplitude modulated signal with zero crossings on each clock edge. The hybrid coded signal maintains the full integrity of the data signal. The signal is generated using a simple logic and voltage summing node or using a switched current source as shown in Figures 4 and 5 below. For illustrative purposes, a 2:1 relationship is used in Figures 2A and 2B, but any ratio can be implemented.

3A is a block diagram of an embodiment of a receiver 300 that receives a differential daisy chain signal at its input and recovers a clock signal and a data signal from the differential daisy chain signal. Receiver 300 includes a differential receiver 302. The differential receiver 302 converts the differential daisy chain signal into a single ended signal that is supplied to the first inputs of the comparators 304, 306, and 308. The thresholds Vth1, Vth2, and Vth3 are input to the second inputs of the comparators 304, 306, and 308, respectively, and define signal levels for various daisy chain states. The outputs of comparators 304, 306, and 308 are input to a decoder and filter 310 that decodes the input signal into a CLK signal and a DATA signal. The zero crossing defines the CLK signal, where the positive and negative voltage swings are related to the '0' and '1' states of the daisy chain signal. That is, each zero crossing detected by comparator 306 is converted to the edge of the clock signal. Moreover, comparators 304 and 306 convert pulses (e.g., positive and negative voltage swings) into digital values of the data signal.

FIG. 3B is a timing diagram corresponding to the receiver 300 of FIG. 3A. The daisy chain signal is a differential input signal that is input to the differential receiver 302. Signals A, B, and C correspond to the outputs of comparators 304, 306, and 308, respectively. In this example, comparator 306 compares the differential daisy chain signal to the threshold Vth2. The threshold Vth2 has a voltage of 0 or a nominal voltage. Therefore, the comparator 306 detects zero crossings and directly Restore clock signal B. The thresholds Vth1 and Vth3 are set to detect high level conversion of the daisy chain signal. The threshold Vth1 is set to detect high amplitude pulses and ignore low amplitude pulses. Comparator 304 uses a threshold Vth1 output signal A, which has a pulse for each high amplitude pulse. Similarly, threshold Vth3 is set to detect only low amplitude pulses, with comparator 308 outputting a signal C having a pulse for each low amplitude pulse on the daisy chain signal. The decoder and filter 310 resolves signals A, B, and C into CLK signal DATA signals. In one embodiment, the decoder and filter 310 includes a clock filter, a data filter, and a data retiming function, as described in more detail below in FIG.

FIG. 3C is a block diagram of an alternate embodiment of receiver 330. Like receiver 300, receiver 330 includes comparators 304, 306, and 308, as well as a decoder and filter 310. However, the receiver 330 does not have the differential receiver 302 as in the receiver 300. Rather, the first daisy chain signal is provided directly to the first inputs of comparators 304, 306, and 308. The second daisy chain signal (inversion of the first daisy chain signal) is provided to the second input of the comparator 304 modified by the threshold Vth1, the second input provided directly to the comparator 306, and to the modified by the threshold Vth3 The second input of comparator 308.

4 is a schematic diagram of an embodiment of a transceiver 400 that is constructed using a current source. Alternative configurations based on voltage sources are also possible. Transceiver 400 includes a transmitter that is generally shown at 410 and a receiver that is shown generally at 430. Transceiver 400 receives control signals and their corresponding inverted signals at inputs A, B, C, D, E, and F , and . Lines 406-1 and 406-2 are advanced to the differential line that is external to the pin (e.g., on an external device in some embodiments) to a communication medium (e.g., communication medium 106). Lines 408-1 and 408-2 supply power to transceiver 400. The transceiver 400 operates in the four modes of the normal mode, the reception mode, the transmission mode, and the sleep mode described below.

The transceiver 400 further includes a receive amplifier 402, a zero crossing detector 404, and a sleep mode receiver 403. The transceiver further includes a switching circuit that is shown generally by 420. Figure 4 further illustrates a plurality of switched current sources that combine clock and Manchester encoded data into a mixed encoded signal. Transmitter 410 includes a plurality of transmit current sources 412 shown as 1x unit sources and 3x unit sources, while receiver 430 controls a plurality of receive current sources 432 shown as 0.289x units. These ratios produce specific waveforms during transmission and reception and are adapted to specific external circuit values. However, it should be understood that other values are used in other embodiments.

During the normal mode, there is no activity on the daisy chain and the two receivers of each transceiver 400 in the daisy chain system are ready to receive signals. In the normal mode, transceiver 400 waits to detect daisy-chain signals arriving at lines 406-1 and 406-2 connected to the two receivers. In the normal mode, the receive amplifier 402 and the zero crossing detector 404 of the drive current source 432 function. When receiver 430 is in the normal mode, receive amplifier 402 acts and converts the input waveform voltage level and timing for subsequent decoding. Zero crossing detector 404 generates receiving servo signal B and . Receiving servo signal B and Current source 432 is controlled and functions during normal mode and receive mode.

During the receive mode, transceiver 400 detects a transmission from the daisy chain on the receive port. The transceiver 400 relays the information transmitted on the transmission to the next transceiver along the daisy chain. Each component that functions during normal mode also functions during the receive mode. Bypass switches 421-1 and 421-2 have low open capacitance so as not to B and And receiving the servo signal load input waveform generated by the current source 432. Receive servo current source 432 is adjusted to make any changes to R3. When the transceiver 400 is in the receiving mode, the signal B and Maintain the bus idle state and promote the correct DC value. In normal mode or receive mode, current source C, , D and Closed because it is in the transfer function state. Switch A is open in the receive mode, so the path from input to receive servo current source 432 passes through resistor R4.

Signal C and A 1x unit current source switch drive signal that controls a 1x unit transfer current source 412 that is deactivated during the receive mode. Signal D and A 3x unit current source switch drive signal that controls the 3x unit transfer current source 412, which is also disabled during the receive mode. As shown below, Figure 5 is the driving signal C, , D and An exemplary encoder.

In the transmission mode, the transceiver 400 transmits the encoded signal along the daisy chain. Signal B and when transceiver 400 is in transmission mode Deactivate and control signal C, , D and Open. Switch A is closed, so resistor R4 is bypassed, creating a low impedance path to return resistor R3. The output level is set by the value of R3 and the current value through R3. The current through R3 has C. , D and Current source 412 is caused. Receiver 430 is deactivated during the transmission mode.

The sleep mode causes transceiver 400 to enter a low current state in which receive amplifier 402 and zero crossing detector 404 are powered down and sleep mode receiver 403 is powered. Control signal B, , C, , D and Turns off in sleep mode. Switch E is open during sleep mode. In one embodiment, resistor R2 has a high value resistance compared to the resistance of resistor R1. Compared to the normal mode, in which the switch E is closed and the resistor R2 is bypassed, current flows through the resistors R2 and R1 in the sleep mode. In an embodiment, there is a buffer between the center connections of resistors R1 and R3.

Sleep mode receiver 403 wakes transceiver 400 from sleep mode when it detects a zero crossing on path 139-1 or 139-2. In an embodiment, sleep mode receiver 403 processes the 4 kHz input clock signal and operates at relatively low power. Once the wake condition is identified, the sleep mode receiver is turned off as needed and the transmission mode receiver 402 is activated. In an embodiment where the transceiver 400 is part of a daisy chain, the transmitter 410 is also activated and used to relay the wake-up signal to the next link device.

The transmit mode receiver 402 also supplies a zero crossing detector 404 that provides a communication idle state servo signal during the receive mode. Such functionality can be used to maintain compatibility with a variety of transmission circuits and is not used in the examples shown in Figures 1A and 1B in some examples. The communication idle state is caused by clock signals and data signals that are both at predetermined logic levels. In an embodiment, all transmissions begin with a bus in the idle state and the bus always returns to an idle state after transmission. Receiver 430 is forced into the bus idle state (if not previously in this state) after the communication has timed out as part of the error recovery system. In some embodiments, the zero crossing detector 404 for the servo function is the same as the detector for clock recovery, depending on the filtering position for high frequency (HF) noise cancellation. In other embodiments, zero crossing detector 404 does not perform clock recovery.

The transceiver 400 further includes a switching circuit, shown generally at 420, that switches via a signal that triggers the transceiver 400 between a transmission mode and a reception mode. Switching circuit 420 includes a shunt resistor R4 and bypass switches 421-1 and 421-2 that receive the signal provided at A. Signal A drives switch circuit 420, which bypasses resistor R4 when transceiver 400 is in the transmit mode. When the transceiver 400 is receiving, the resistor R4 isolates the drive impedance from the external circuit impedance. Assuming an ideal switch, the exemplary value of resistor R4 is 10 kΩ; however, any suitable resistance value can be used. When the source resistor R3 is sized, the turn-on resistance of the bypass switches 421-1 and 421-2 is taken into consideration. Resistor R3 interacts with the current sources of both transmitter 410 and receiver 430 and provides a drive level setting for the transmitter source impedance and transmission signal level. Exemplary values for R3 include 200 Ω, 150 Ω, and 100 Ω or any other suitable resistance value.

Signal E drives switches 422-1 and 422-2, and switches 422-1 and 422-2 bypass sleep mode bias resistor R2 to have a higher bias current in the transmit mode. Resistor R2 provides bias generation during the sleep mode. Resistor R1 generates a bias voltage during the transfer mode. In another embodiment, an additional switch is used to isolate the bias network in the off mode.

For example, using non-volatile memory or mask unit current source values can be programmed. In one example, the 2.5 mA and 4 mA currents are used with the exemplary resistors R1-R4 values discussed above and using an external circuit such as that described below in Figure 9, the external circuit component values are shown in Table I above. The exemplary selected current source values are 2.5 mA, 4 mA, and 6.5 mA, but can be any suitable current. In this embodiment, when the transceiver 400 is transmitting, the captured The theoretical average current is then close to twice the unit current value.

In an alternate embodiment of FIG. 4, the current source is reconfigured such that the transmitter current source 412 is located to the left of the switching circuit 420 and the receiver current source 432 is located to the right of the switching circuit 420. This improves current consumption and signal level accuracy.

FIG. 5 is a schematic diagram of an embodiment of an encoder 500. In this embodiment, the encoder 500 receives CLK, DATA and transmits an enable (Tx enable) signal and outputs an intermediate signal C, , D and Transmitter encoding circuit. Transmitter encoding circuit 500 includes two inverters 510 and four AND gates 520. D, , C, The drive signal is used to correctly encode the data stream into an encoded mixed signal.

In an embodiment, the transmission encoding circuit 500 is in C, , D and It is coupled to the transmitter 410 of FIG. In an embodiment, the transmitter encoding circuit 500 provides an additional edge rise function that reduces the unit conversion rise time while helping to maintain the clock recovery timing. The system immediately turns on the associated 3x current source at the beginning of each 1x conversion, amplifies the waveform and produces a similar zero crossing timing for both 1x to 3x conversion and 3x to 1x conversion.

6 is a timing diagram of an embodiment of a signal in the circuits of FIGS. 4 and 5. In an embodiment, Figure 6 implements the same final result as implemented in Figure 2A, but shows the intermediate driver signal D, , C and Transmitter 400 uses this signal to produce an encoded mixed signal output. The encoded mixed signal is the final output of the transceiver 400 of Figure 4, such as Manchester encoded data, without the intermediate steps being shown.

The CLK, DATA, and Tx enable signals are input to the transmission encoding circuit 500, and the transmission encoding circuit 500 outputs D, , C, To the transceiver 400. The transmit enable signal (Tx enable) activates the transmitter 410 and has a logic high when the transceiver 400 transmits. Transmitter 410 can transmit when a device coupled to transceiver 400 (e.g., device 142-1) wants to transmit a message or when receiver 430 receives a message on a daisy chain to relay through the next daisy chain. .

As shown in Figure 6, the encoded signal is amplitude modulated (having amplitudes -3, -1, 1 and 3, referred to as suitable unit values) and has a zero crossing on each clock edge. Because there is a zero crossing on each clock edge, CLK can be recovered directly. That is, each zero crossing of the received amplitude modulated signal can be converted to the edge of the clock signal recovered therefrom.

FIG. 7 is a schematic diagram of an embodiment of a receiver 700. Receiver 700 performs clock recovery, signal reconstruction, filtering on the receiver end (e.g., the receiving portion of second transceiver 104 in communication systems 100, 150) and retimed the data. The decoder 700 includes a data filter 702, a data retiming block 704, a gain circuit 706, a clock filter 708, an oscillator 710, and a zero crossing detector 712.

In an embodiment, the receiver 700 performs the inverse function to decode the data that the transmitter does encode. An amplitude modulated signal (e.g., an encoded signal) is provided at the input of zero crossing detector 712 that recovers the clock (CLK) signal (w). The clock signal can be converted to the edge of the clock signal by converting each zero crossing of the amplitude modulated signal.

The data signal can be recovered by converting the voltage level of the amplitude modulation signal to the digital value of the data signal. In an example, an amplitude modulation signal (example) For example, the encoded signal is modified by gain 706, which is then subtracted from the recovered clock signal w to produce a noisy recovered data signal (x) (amplitude limited signal). Signal x is the first stage decoded data signal and is provided to the input of zero crossing detector 714. Filtering is applied to this feature to help reduce the effects of high frequency noise. Zero crossing detector 714 outputs a lower noise version of signal x(y). The data filter 702 further uses a counter based filtering operation to recover the data signal (z) and reduce the noise of the signal y.

Data retiming block 704 retimes data signal z to become a clock cycle thereafter. A delay of one clock cycle is provided to the data signal z between the daisy chain reception and the relayed signal output to accommodate the filtering of the data filter 702. The output of receiver 700 enables the signal to be transmitted at the beginning of the second daisy chain clock cycle such that the first transmission clock cycle contains the first data bit. For example, the transceiver 104 includes a receiver 700 that decodes the received data and prepares it for transmission by a transmitter in the transceiver 104. In an embodiment, the receiver 700 is part of a daisy chain network. Other methods of data signal recovery are possible, including direct signal threshold detection using single-ended signals.

FIG. 8 is an exemplary timing diagram corresponding to the receiver of FIG. Figure 8 shows the amplitude relationship between the incoming coded signal (shown in solid lines) and the recovered clock w (shown in dashed lines) and the data signals x, y and z as described above. The short pulses shown in data signal z are removed by data filter 702.

9 is another exemplary timing diagram corresponding to the receiver of FIG. In this example, the input signal and output signal relationship are shown for use as receiver 700, for example, as part of the daisy chain communication system of Figure 1C. Receiver 700 The extra function is to ensure that the minimum pulse width is such that the pulse width shorter than the specified length is reproduced with the minimum allowable width. This applies to both positive and negative pulses and limits the cumulative effects of clock jitter caused by foreign noise sources such as EMI. The minimum pulse width is dependent on the daisy chain clock frequency and is generated by multiple cycles of the oscillator 710. For example, with a 500 kHz daisy-chain clock and a 4 MHz system oscillator 710 (daisy chain clock rate = oscillator rate / 8) produces a minimum pulse of 3 oscillator cycles that ensures correct operation of the oscillator tolerance of up to 15% width. When the transceiver is in the normal communication mode, the oscillator 710 operates continuously. The second decoding function restores the data signal (see, for example, data decoders 238 and 278 of Figures 2A and 2B). In Figure 9, pulse 902 has been modified from the corresponding pulse in signal w to a minimum pulse, which is a short pulse.

In an embodiment, the incoming differential signal is converted to a single-ended signal and mixed with the recovered clock to regenerate the data signal. The incoming signal is positively calibrated for this process. The value of gain 706 in Figure 7 described above, for example, 0.866, provides the correct level for the circuit of Figure 2B with a 2.5 mA unit current and is referred to as a 1 V peak-to-peak recovery clock signal, external circuit components in Table I above Given in .

FIG. 10 is a schematic diagram of an embodiment of an encoder 1000. Encoder 1000 includes logic and voltage summing nodes that mix the CLK signal with the Manchester encoded data signal to produce a mixed encoded signal. The XOR gate 1002 receives the CLK signal and the data signal and outputs a Manchester encoded data signal. This signal is input to a zero crossing detector 1012 which converts the Manchester encoded data signal into a voltage level programmed signal. In this embodiment, the zero-crossing detector 1012 is directed to The logic high input and output 0.333 V signal, and the logic low input and output -0.333 V signal.

Similarly, XOR gate 1004 outputs a signal to zero-crossing detector 1014 based on a combination of a logic low signal and a CLK signal. The zero-crossing detector 1014 outputs a 0.667 V signal for a logic high input and a -0.667 V signal for a logic low input. Amplifier 1020 sums the signals from zero-crossing detectors 1014 and 1012 and outputs an amplitude-modulated mixed-coded data signal. The nature of the hybrid coded data signal is such that zero crossings are provided at each clock edge while maintaining full data integrity.

In the present exemplary embodiment, encoder 1000 has a 2:1 relationship between the encoded data calibration value of zero crossing detector 1014 and the encoded data calibration value of zero crossing detector 1012, which provides good noise cancellation. The absolute values of these factors can be selected to provide a nominal 2 V peak-to-peak signal (4 V peak-to-peak differential) at each output. Increasing this output swing further improves robustness when the receiver voltage swing is similarly calibrated. The voltage swing on the receiver (eg, receiver 230) is less than the voltage swing on the transmitter (eg, transmitter 210) and is determined by the ratio value of an external component (eg, the resistor in FIG. 1).

Figure 11 shows an example of different signals associated with the encoder shown in Figure 10. FIG. 11 illustrates a clock signal 1102, a data signal 1104, an XOR signal 1106, and an output signal 1108. In an example, XOR signal 1106 includes a Manchester encoded data signal output by XOR gate 1002.

Signal 1108 is a mixed coded data signal output by amplifier 1020. Signal 1108 is an amplitude modulated square wave signal in which different voltage levels of square wave pulses correspond to different data values. As an amplitude modulated square wave signal, the letter The amplitude of the number 1108 corresponds to a data value (eg, a digital value). In one example, the voltage levels associated with digit 0 and digit 1 can be +/- 1 V and +/- 3 V, respectively.

Signal 1108 can include a plurality of pulses 1110, 1112, 1114. Each pulse 1110, 1112, 1114 corresponds to the period of the clock signal 1102. The pulses include positive and negative voltage swings in the output signal 1108. In the illustrated example, the initial pulse 1110 corresponds to a digit 1 (eg, plus or minus 3 volts wobble) represented by a high voltage level. Therefore, the initial pulse 1110 rises up to +3 V and down to -3 V. Thus, the initial pulse 1110 maintains a balanced signal of +3 volts and -3 volts.

Subsequent pulses 1112 and 1114 can also have a substantially balanced signal. This is done to generate a DC balanced output signal 1108. That is, this can be done to produce an output signal 1108 that is substantially centered at approximately 0 volts. In an example, the second pulse 1112 of the signal 1108 corresponds to a digit 0 (eg, plus or minus 1 volt swing) represented by a low voltage level. Therefore, the mixed coded data signal 1108 is an amplitude modulated signal.

12 is a schematic diagram of an embodiment of a decoder 1200. The decoder 1200 includes a differential input stage 1202 followed by a limit stage 1204 having a differential output. The decoder 1200 provides a load terminal that provides a differential input signal at a nominal bus idle voltage that allows the use of a receiver with an alternate (eg, capacitive) coupling circuit configuration. The bus idle voltage termination circuit is typically not used in the system of Figure 1. In one embodiment, resistors 1206-1 and 1206-2 in decoder 1200 have a nominal high value, for example, 100 kΩ. The limit value is the bus idle state value at the receiver input and the rest. Enable The circuit detects the arrival of the first transmission edge and enables the leveling stage 1204. The restriction stage 1204 is deactivated so that the output after the data transmission conforms to the bus idle state. At the end of the transfer, the bus is always idle. The enable circuit primarily provides the correct initial state for device startup and further corrects for any error bus idle state.

13 is an exemplary timing diagram of the decoder of FIG. Note that the output data signal is delayed by one clock cycle from the input signal. The source clock is extended by one clock cycle to facilitate decoding with delayed data output. In this embodiment, all communication sequences are a plurality of 8 bits.

14 is a block diagram of an embodiment of an electronic system 1400. The electronic system 1400 includes a lithium (Li) ion battery pack 1410, a power controller 1412, and a motor 1414. Li-ion battery pack 1410 is adapted to include a plurality of balanced integrated circuits (ICs) 1401-1, 1401-2 through 1401-N that are connected via a robust 2-wire daisy chain communication system (100, 150) . The balance ICs 1401-1, 1401-2 through 1401-N monitor the cells in the battery 1410. The balancing ICs 1401-1, 1401-2 through 1401-N each include one or more transceivers and are daisy-chained to the communication media 106-1 through 106-N. Accordingly, the plurality of balanced ICs 1401-1, 1401-2 through 1401-N and communication media 106-1 through 106-N may correspond to the daisy chain system 140 of FIG. 1C. That is, the balance IC 1401-1 can include a device 142-1 coupled to the transceiver 150-1, wherein the first transceiver 150-1 of the first balance IC 1401-1 can be coupled to the second balance IC 1401-2 Two transceivers 150-2.

One embodiment of electronic system 1400 is a hybrid electric vehicle. In this embodiment, the battery pack 1410 is a high voltage battery system that processes up to 400 V. There are balance ICs 1401-1, 1401-2, 1401-N for each of the 12 battery cell groups that communicate through the daisy chain system described above. The voltage difference between the top and bottom of the daisy chain is 400 V, and each has a level of 40 V. Due to the reactive nature of lithium in lithium ion battery 1410, there is a risk of explosion in the event of overheating or overcharging of battery 1410. Embodiments of the isolated communication system described herein facilitate the prevention of such explosions by using monitoring balance ICs 1401-1, 1401-2, 1401-N and their charge depletion functions.

In another embodiment, the battery management system 1400 is installed in a gas-electric hybrid or electric vehicle. Figure 15 provides more details of the connection between the balancing ICs 1401-1 and 1401-2 of Figure 14 of a 12-cell system. If the voltage source is suddenly disconnected, the inductive spike can propagate through the battery pack 1410. The nominal 40 V can be raised to 120 V, and any connection between the balancing ICs 1401-1, 1401-2, 1401-N causes a portion of the spike. In one example, communication medium 106-1 causes a transient spike of 70 V. Since the communication system is fully electrically isolated and protected from this voltage transient level, the communication system can survive transients without damage and expose the electronic device to dangerous voltages or temperatures.

16 is a flow diagram of an embodiment of a method 1600 of transmitting material via an isolated communication system (e.g., communication system 100, 170). A data signal is received on a first transceiver, such as first transceiver 102 (block 1610). The first transceiver encodes the data signal (block 1620) and combines it with the clock signal to produce a hybrid encoded data signal (block 1630). The first transceiver transmits the hybrid encoded data signal (block 1640). The hybrid encoded data signal is transmitted, for example, via a differential and AC coupled network, and the differential and AC coupled network connects the first transceiver 102 to the second transceiver via the communication medium 106. 104. The second transceiver receives the hybrid encoded data signal (block 1650). The second transceiver extracts the clock signal and decodes the data signal (block 1660). In one embodiment, the clock signal is extracted by detecting a zero crossing of the mixed encoded data signal.

Embodiments described herein provide improved isolated communication, reduced EMI emissions and sensitivity, and enhanced transient voltage protection. Some embodiments provide a differential AC coupling network that eliminates EMI on the receiver and isolates transient effects between communication media ends. The embodiments described herein are not limited by the type of integrated circuit. Embodiments are also not limited to any particular type of processing technique, such as CMOS, bipolar, or BICMOS that can be used to fabricate the present disclosure. Other additions, subtractions, or modifications are obvious in light of the present disclosure and are intended to fall within the scope of the appended claims.

A number of embodiments of the invention are defined by the scope of the following claims. It will be appreciated, however, that various modifications may be made to the described embodiments without departing from the spirit and scope of the invention. The features and aspects of the specific embodiments described herein may be combined or substituted with the features and aspects of other embodiments. Accordingly, other embodiments are within the scope of the following claims.

100‧‧‧Communication system

102‧‧‧First transceiver

104‧‧‧Second transceiver

106-1‧‧‧Communication media

106-2‧‧‧Communication media

106-N‧‧‧Communication media

107‧‧‧Clamp

112‧‧‧Differential capacitor

113-1‧‧‧Resistors

113-2‧‧‧Resistors

114-1‧‧‧ capacitor

114-2‧‧‧ capacitor

118‧‧‧Transformers

119-1‧‧‧First resistor

119-2‧‧‧second resistor

119-3‧‧‧ Third resistor

119-4‧‧‧fourth resistor

119-5‧‧‧ fifth resistor

119-6‧‧‧ sixth resistor

120-1‧‧‧ first

120-2‧‧‧Second

120-3‧‧‧third

120-4‧‧‧Fourth

121‧‧‧Transformers

122‧‧‧Differential capacitor

123-1‧‧‧Resistors

123-2‧‧‧Resistors

124-1‧‧‧ capacitor

124-2‧‧‧ capacitor

131-1‧‧‧Response resistor

131-2‧‧‧Response resistor

132‧‧‧Differential drive

133‧‧‧ trigger driver

134‧‧‧Transport driver

135‧‧‧Differential drive

136‧‧‧ trigger driver

137-1‧‧‧Response resistor

137-2‧‧‧ feedback resistor

138‧‧‧Transport driver

139-1‧‧‧High path

139-2‧‧‧Low path

140‧‧‧System

142-1‧‧‧ device

142-2‧‧‧second device

142-3‧‧‧ third device

142-N‧‧‧Other devices

150-1‧‧‧First Transceiver

150-2‧‧‧Second transceiver

150-3‧‧‧ Third Transceiver

150-M‧‧‧ transceiver

152‧‧‧System clock

170‧‧‧Communication system

200‧‧‧ transceiver

210‧‧‧Transporter

212‧‧‧Encoder

214‧‧‧Multiplier

216‧‧‧sumer

220‧‧‧ Receiver

230‧‧‧ Receiver

232‧‧‧Detector

234‧‧‧Multiplier

236‧‧‧sumer

238‧‧‧ Data Decoder

250‧‧‧ transceiver

260‧‧‧transmitter

262‧‧‧XOR gate

270‧‧‧ Receiver

278‧‧‧XOR gate

278‧‧‧Data Decoder

300‧‧‧ Receiver

302‧‧‧Differential Receiver

304‧‧‧ Comparator

306‧‧‧ Comparator

308‧‧‧ comparator

310‧‧‧ filter

330‧‧‧ Receiver

400‧‧‧ transceiver

402‧‧‧Amplifier

403‧‧‧ Receiver

404‧‧‧Detector

406-1‧‧‧ line

406-2‧‧‧ line

408-1‧‧‧ line

408-2‧‧‧ line

410‧‧‧Transporter

412‧‧‧current source

420‧‧‧Switch circuit

421-1‧‧‧ Bypass switch

421-2‧‧‧ Bypass switch

422-1‧‧‧Drive Switch

422-2‧‧‧Drive Switch

430‧‧‧ Receiver

432‧‧‧current source

500‧‧‧Encoder

510‧‧‧Inverter

700‧‧‧ Receiver

702‧‧‧Data Filter

704‧‧‧Retiming Square

706‧‧‧gain circuit

708‧‧‧clock filter

710‧‧‧Oscillator

712‧‧‧Detector

714‧‧‧Detector

902‧‧‧pulse

1000‧‧‧Encoder

1002‧‧‧XOR gate

1004‧‧‧XOR gate

1012‧‧‧Detector

1014‧‧‧Detector

1020‧‧Amplifier

1102‧‧‧ clock signal

1104‧‧‧Information signal

1106‧‧‧XOR signal

1108‧‧‧ Output signal

1110‧‧‧pulse

1112‧‧‧pulse

1114‧‧‧pulse

1200‧‧‧Decoder

1202‧‧‧ input level

1204‧‧‧Restricted

1206-1‧‧‧Resistors

1206-2‧‧‧Resistors

1400‧‧‧ system

1401-1‧‧‧Integrated Circuit (IC)

1401-N‧‧‧Integrated Circuit (IC)

1401-2‧‧‧Integrated Circuit (IC)

1410‧‧‧Battery Pack

1412‧‧‧Power Controller

1414‧‧‧Motor

1600‧‧‧ method

1610‧‧‧Box

1620‧‧‧ square

1630‧‧‧Box

1640‧‧‧ square

1650‧‧‧ square

1660‧‧‧

The exemplified embodiments are described in detail with particular reference to the accompanying drawings.

1A is a schematic diagram of an embodiment of a communication system.

1B is a schematic diagram of another embodiment of a communication system.

1C is a block diagram of an embodiment of a system utilizing the communication system of FIGS. 1A and/or 1B.

2A and 2B are block diagrams of alternative embodiments of a transceiver for the system of FIG. 1A, FIG. 1B, or FIG. 1C.

3A is a block diagram of an embodiment of a receiver for the system of FIG. 1A, FIG. 1B, or FIG. 1C.

FIG. 3B is an exemplary timing diagram corresponding to the receiver of FIG. 3A.

3C is a block diagram of an alternate embodiment of a receiver for the system of FIG. 1A, FIG. 1B, or FIG. 1C.

4 is a schematic diagram of an embodiment of a transceiver for the system of FIG. 1A, FIG. 1B, or FIG. 1C.

5 is a schematic diagram of an embodiment of an encoder for use with the transceiver of FIG.

6 is an exemplary timing diagram of signals in the circuits of FIGS. 4 and 5.

7 is a schematic diagram of an embodiment of a receiver for the system of FIG. 1A, FIG. 1B, or FIG. 1C.

8 and 9 are exemplary timing diagrams corresponding to the receiver of FIG.

10 is a schematic diagram of another embodiment of an encoder for use with the transceiver of FIG. 2A.

11 is an exemplary timing diagram of the encoder of FIG.

12 is a schematic diagram of an embodiment of a decoder for use with the transceiver of FIG. 2A.

13 is an exemplary timing diagram of the decoder of FIG.

Figure 14 is an illustration of a battery for use with the system of Figure 1C. Example block diagram.

Figure 15 is a block diagram of an embodiment of two cells of the battery of Figure 14.

16 is a flow diagram of an embodiment of a method of transmitting data via the isolated communication system of FIG. 1A, FIG. 1B, or FIG. 1C.

Features of different descriptions are not drawn to scale, but are drawn to emphasize particular features associated with the illustrative embodiments.

100‧‧‧Communication system

102‧‧‧First transceiver

104‧‧‧Second transceiver

106‧‧‧Communication media

107‧‧‧Clamp

112‧‧‧Differential capacitor

113-1‧‧‧Resistors

113-2‧‧‧Resistors

114-1‧‧‧ capacitor

114-2‧‧‧ capacitor

118‧‧‧Transformers

119-1‧‧‧First resistor

119-2‧‧‧second resistor

119-3‧‧‧ Third resistor

119-4‧‧‧fourth resistor

119-5‧‧‧ fifth resistor

119-6‧‧‧ sixth resistor

120-1‧‧‧ first

120-2‧‧‧Second

120-3‧‧‧third

120-4‧‧‧Fourth

122‧‧‧Differential capacitor

123-1‧‧‧Resistors

123-2‧‧‧Resistors

124-1‧‧‧ capacitor

124-2‧‧‧ capacitor

131-1‧‧‧Response resistor

131-2‧‧‧Response resistor

132‧‧‧Differential drive

133‧‧‧ trigger driver

134‧‧‧Transport driver

135‧‧‧Differential drive

136‧‧‧ trigger driver

137-1‧‧‧Response resistor

137-2‧‧‧ feedback resistor

138‧‧‧Transport driver

139-1‧‧‧High path

139-2‧‧‧Low path

Claims (25)

A method for transmitting a signal, the method comprising: generating a Manchester encoded data stream; combining the Manchester encoded data stream with an amplified clock signal to produce zero on each edge of the amplified clock signal Intersecting an amplitude modulation signal; and transmitting the amplitude modulation signal via a communication medium. The method of claim 1, wherein combining the Manchester encoded data stream with an amplified clock signal comprises subtracting a voltage of the Manchester encoded data stream from a voltage of the amplified clock signal. The method of claim 1, comprising: amplifying the clock signal to produce the amplified clock signal, wherein the amplifying comprises generating a signal having a peak-to-peak amplitude greater than a peak-to-peak amplitude of the Manchester encoded data stream. The method of claim 3, wherein the amplifying comprises generating a signal having a peak-to-peak amplitude that is twice the peak-to-peak amplitude of the Manchester encoded data stream. The method of claim 3, wherein generating a Manchester encoded data stream comprises XOR the clock signal and a data signal. The method of claim 1, wherein transmitting the amplitude modulation signal comprises transmitting the amplitude modulation signal as a square wave. A method for transmitting an amplitude modulated signal, the method comprising: transmitting a plurality of square wave pulses having an edge corresponding to an edge of a clock signal and a digital value corresponding to a data signal The amplitude includes a square wave pulse having a transmission amplitude greater than a threshold amplitude when a data signal is at a first digit level, and a transmission amplitude less than the threshold amplitude when the data signal is at a second digit level Wave pulse. The method of claim 7, wherein the threshold amplitude corresponds to a positive voltage level when positive and negative to a negative voltage, and wherein transmitting the plurality of square wave pulses comprises: when the data signal and the When the clock signal is at the first digit level, transmitting a pulse having a positive amplitude higher than the positive voltage level; transmitting the negative amplitude when the data signal is at the first digit level and the clock signal is at a second voltage level a pulse lower than the negative voltage level; when the data signal is at the second digit level and the clock signal is at the first digit level, transmitting a pulse having a positive amplitude lower than the positive voltage level; The data signal and the clock signal are at the second digit level to transmit a pulse having a negative amplitude higher than the negative voltage level. The method of claim 8, wherein transmitting a pulse having a positive amplitude higher than the positive voltage level comprises transmitting the amplitude of the pulse having a positive amplitude that is less than about one-third of an amplitude of a pulse of the positive voltage level. The method of claim 7, wherein transmitting the plurality of pulses comprises transmitting a square wave pulse. A method for receiving an amplitude modulation (AM) signal, the method package Comprising: recovering a clock signal by detecting a zero crossing of the AM signal and converting each zero crossing of the AM signal into an edge of the clock signal; and converting the voltage level of the AM signal to the edge The data signal is recovered by a digital value of the data signal. The method of claim 11, wherein the converting voltage level comprises detecting a pulse of the AM signal above an upper limit amplitude and a pulse below a lower limit amplitude; wherein a pulse adjacent to a pulse below a lower limit amplitude is higher than One of the upper amplitude amplitude pulses is converted to a first digit value of the data signal; and a negative pulse adjacent to the negative amplitude between the upper limit amplitude and the lower limit amplitude is between the upper limit amplitude and the lower limit amplitude One positive pulse is converted to a second digit value of the data signal. The method of claim 11, wherein converting the voltage level of the AM signal to a digital value comprises mixing the clock signal with the AM signal. A transmitter comprising: an encoding circuit configured to receive a clock stream and a data stream, the encoding circuit configured to combine the clock stream and the data stream into one or more intermediate a plurality of current sources coupled to the encoding circuit and configured to receive the intermediate signals, wherein the encoding circuit and the plurality of current sources are configured to generate an amplitude modulated signal having a corresponding amplitude modulated signal The edge of the edge of the clock stream and an amplitude corresponding to the data stream. The transmitter of claim 14, wherein the one or more intermediate signals Includes a Manchester encoded stream. The transmitter of claim 14, wherein the plurality of current sources are configured to generate a pulse having an amplitude greater than a threshold amplitude when the data stream is at a first digit level and when the data stream is at a second digit The bit timing transmission amplitude is less than one pulse of the threshold amplitude. The transmitter of claim 14, wherein the plurality of current sources comprises a first current source and a second current source, the second current source configured to generate a current greater than the first current source; wherein the one or The plurality of intermediate signals includes control signals coupled to the first and second current sources, the control signals configured to turn on the first current source based on the data stream at a first digit level and based on being in a second The data stream of the digital level opens the second current source. The transmitter of claim 14, wherein the one or more intermediate signals are configured to generate a square wave signal from the one or more current sources. A receiver configured to receive an amplitude modulation (AM) signal, comprising: a first comparator configured to detect a pulse above the upper limit of the AM signal; a second comparator, the group The state is to detect a zero crossing of the AM signal; a third comparator configured to detect a pulse below the lower limit of the AM signal; and a decoder circuit configured to: Converting each zero crossing detected by the comparator to an edge of the clock signal to recover a clock signal; and The data signal is recovered by converting the pulses detected by the first and third comparators into digital values of the data signal. The receiver of claim 19, wherein restoring a data signal comprises converting a pulse detected by the first comparator adjacent to a pulse detected by the third comparator into a first one of the data signals The digit value and two adjacent zero crossings that do not have a pulse detected by the first comparator or the third comparator are converted to a second digit value of the data signal. A daisy chain communication system comprising: a first device configured to provide a first data signal for transmission; and a first transceiver coupled to the first device, the first transceiver configuration In order to transmit a first amplitude modulation signal having an edge corresponding to an edge of a clock signal and an amplitude corresponding to a digit value of the first data signal, the first transceiver has a coupling to a first port and a second port of a first communication medium; a second transceiver having a third port and a fourth port coupled to the first communication medium, the second transceiver including a decoder Decoder configured to extract the clock signal and parse the first data signal from the first amplitude modulation signal; a second device coupled to the second transceiver and configured to transmit from the second transceiver Receiving the first data signal and providing a second data signal for transmission; a third transceiver coupled to the second device, the third transceiver configured to transmit a second amplitude modulation signal, Second amplitude modulation signal Having an edge corresponding to an edge of the clock signal and an amplitude corresponding to a digital value of the second data signal, the third transceiver having a fifth port and a sixth port coupled to a second communication medium; a fourth transceiver having a seventh port and an eighth port coupled to the second communication medium, the fourth transceiver including a decoder configured to extract the clock signal and from the A second amplitude modulation signal parses the second data signal; and a third device coupled to the fourth transceiver and configured to receive the second data signal from the fourth transceiver. The daisy-chain communication system of claim 21, wherein the first and second transceivers are coupled to the first communication medium via one of a capacitor or a transformer; and wherein the third and fourth transceivers are transmitted through a capacitor or a transformer One of the ones is coupled to the second communication medium. A daisy chain communication system according to claim 21, comprising a cell balancing system for balancing a voltage between the plurality of battery cells, wherein the first device monitors a first balancing IC of the first one or more battery cells The second device monitors a second balancing IC of the second one or more battery cells, and the third device monitors a third balancing IC of the third one or more battery cells. A daisy-chain communication system according to claim 23, wherein the first, second and third devices are mounted in a battery pack for use in an electric vehicle or a gas-electric hybrid vehicle. The daisy chain communication system of claim 21, comprising: One or more additional devices communicatively coupled to the third device, the one or more additional communication media having transceivers on their respective ends.