Transmission circuit, electronic circuit, and transceiver circuit

Abstract

To improve reception performance while suppressing increase in transmission energy.SOLUTION: A transmission circuit comprises a transmission unit that outputs a waveform including a plurality of pulse waveforms in response to an input signal. The pulse waveforms include a first transmission pulse waveform and a second transmission pulse waveform following the first transmission pulse waveform. The first transmission pulse waveform has an amplitude larger than that of the second transmission pulse waveform.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] Embodiments of the present invention relate to a transmission circuit and a transmission / reception circuit.

Background Art

[0002] There is a method of transmitting an input signal from a transmission unit to a reception unit via an insulating element for insulating signal transmission. In insulating signal transmission, there is a method of transmitting a digital signal by a high-level or low-level pulse. Since the insulating element generally has a frequency characteristic of a band-pass filter type, the output waveform output from the transmission unit to the reception unit side via the insulating element is an analog waveform including a pulse waveform from which components other than a specific frequency are removed. The reception unit determines the high level and low level of the digital signal included in the transmitted signal from the received analog waveform and reproduces the information.

[0003] That is, in order to receive the signal included in the input signal, it is necessary to determine the high-level and low-level signals included in the pulse in order to reproduce the pulse based on the output analog waveform.

[0004] However, due to the influence of noise or the like, the high level and low level of some pulses may not be determined for the analog waveform. In such a case, the pulse becomes a bottleneck and the reception performance is limited.

[0005] In order to improve the reception performance of the input signal, it is necessary to increase the amplitude and pulse width of the pulse. That is, there is a problem of increasing the transmission energy which is the energy of the signal output from the transmission unit.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] This embodiment has been made in view of the problems as described above, and an object thereof is to improve reception performance while suppressing an increase in transmission energy.

Means for Solving the Problems

[0008] The transmission circuit of this embodiment includes a transmission unit that outputs a waveform including a plurality of pulse waveforms in response to an input signal. The pulse waveforms include a first transmission pulse waveform and a second transmission pulse waveform behind the first transmission pulse waveform, and the amplitude of the first transmission pulse waveform is larger than that of the second transmission pulse waveform.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the overall configuration of the transmission / reception circuit 1000 according to the present embodiment. FIG. 2 shows the circuit configuration of the transmission pulse generation circuit (transmission pulse generation unit) 110. FIG. 3 shows the transmission signal output by the combination of the trigger signal and the data signal. FIG. 4 shows the ON and OFF of the switch during signal transmission. The transmission / reception circuit 1000 includes a transmission circuit 100, an insulating element 200, and a reception circuit 300. The transmission / reception circuit 1000 is a transmission / reception circuit in which the transmission circuit 100 on the input side and the reception circuit 300 on the output side are insulated by the insulating element 200 which is an electrical insulator and signals are transmitted.

[0011] The transmission circuit 100 outputs an analog waveform (first waveform) according to the input signal. Specifically, the transmission circuit 100 outputs an analog waveform (first waveform) in synchronization with the transition of the input signal. The transmission circuit 100 may also be referred to as a transmission unit. The input signal is, for example, a signal obtained by converting an analog signal output by a current sensor or a voltage sensor into a digital signal. The input signal includes signals that are not the electrical signals to be amplified observed by the current sensor or the voltage sensor, for example, noise and the like. The transition of the input signal indicates a change in the state of the input signal. The transition of the input signal is, for example, a rising edge or a falling edge of the input signal. The transmission circuit 100 includes a transmission pulse generation circuit 110 and a control signal generation unit 120.

[0012] The analog waveform output by the transmission circuit 100 is a waveform including a continuous pulse waveform. The continuous pulse waveform includes not only the case where the interval between pulse waveforms is 0 but also the case where the pulse waveforms are at regular periodic intervals. For example, the case where the interval between pulse waveforms is 1 second is also included.

[0013] For example, when the number N of pulse waveforms (N is a natural number of 2 or more), the transmission circuit 100 transmits the input signal as an analog waveform of N continuous pulse waveforms. The pulse waveform can be made into a Boolean value by discriminating between a high level or a low level based on the amplitude. For example, the analog waveform can be regarded as a digital signal represented by N bits.

[0014] Hereinafter, the number N of pulse waveforms included in the analog waveform will be described as 3. The transmission circuit 100 converts the input signal into an analog waveform having three pulse waveforms and transmits it.

[0015] In this description, among the three pulses output by the transmission circuit 100, the first output pulse is the first transmission pulse (first transmission pulse waveform), the next output pulse is the second transmission pulse (second transmission pulse waveform), and the next output pulse is the third transmission pulse.

[0016] The transmission pulse generation circuit 110 generates a pulse waveform. In this embodiment, the transmission pulse generation circuit 110 generates a pulse waveform by differential current pulses. The transmission pulse generation circuit 110 includes current sources 111_1 to 111_8 and switches 112_1 to 112_8.

[0017] Current sources 111_1, 111_3, 111_5, 111_7 (first current sources) conduct a current of I1. Similarly, current sources 111_2, 111_4, 111_6, 111_8 (second current sources) conduct a current of I2. Switches 112_1, 112_3, 112_5, 112_7 (first switches) are connected to current sources 111_1, 111_3, 111_5, 111_7. Similarly, switches 112_2, 112_4, 112_6, 112_8 (second switches) are connected to current sources 111_1, 111_3, 111_5, 111_7. Switches 112_1 to 112_8 control the output of the current source by opening and closing. For example, when turned ON, the current of the current source flows into the circuit.

[0018] Switches 112_1 to 112_8 are not limited to opening and closing by mechanical contacts for controlling the output of the current source. Switches 112_1 to 112_8 may control the output of the current source by a logic gate. For example, switches 112_1 to 112_8 may be digital circuits such as transistors or integrated circuits (ICs).

[0019] The transmission pulse generation circuit 110 transmits two types of signals, H or L, as a transmission signal by combining transmission pulses with different polarities. Signal H is, for example, a signal indicating the high level of a digital signal, and signal L is, for example, a signal indicating the low level of a digital signal.

[0020] For example, when transmitting signal H, in the first transmission pulse, by turning ON switches 112_1, 112_2, 112_7, 112_8 (first switches) simultaneously, a current of I1 + I2 is output to Iout. Next, in the second transmission pulse, by turning ON switches 112_3, 112_5 simultaneously, a current of -I1 is output to Iout. Finally, in the third transmission pulse, by turning on switches 112_1 and 112_7 simultaneously, the current of I1 is output to Iout.

[0021] That is, when transmitting signal H, as shown in FIG. 4, switch 112_1 is operated in the order of ON, OFF, and ON states. Similarly hereinafter, switch 112_2 is operated in the order of ON, OFF, and OFF states. Switch 112_3 is operated in the order of OFF, ON, and OFF states. Switch 112_4 is operated in the order of OFF, OFF, and OFF states. Switch 112_5 is operated in the order of OFF, ON, and OFF states. Switch 112_6 is operated in the order of OFF, OFF, and OFF states. Switch 112_7 is operated in the order of ON, OFF, and ON states. Switch 112_8 is operated in the order of ON, OFF, and OFF states.

[0022] The current flowing through Iout is output in the order of I1 + I2, -I1, and I1. The first transmission pulse, the second transmission pulse, and the third transmission pulse are output in proportion to the magnitude of the output of the current. That is, since the first transmission pulse is output based on a larger current of I2, it is larger than the third transmission pulse.

[0023] By adjusting the current flowing through the current source, the amplitude of the current of the transmission pulse can be adjusted. For example, by adjusting the current flowing through the current source so as to satisfy the relationship of I2 = 2×I1, the amplitude of the current of the first transmission pulse can be set to three times that of other pulses. In addition, by adjusting the power flowing through the current source, the amplitude of the first transmission pulse can be set to any multiple of other pulses.

[0024] For example, when transmitting signal L, in the first transmission pulse, by turning on switches 112_3, 112_4, 112_5, and 112_6 simultaneously, a current of -(I1 + I2) is output to Iout. Next, in the second transmission pulse, by turning on switches 112_1 and 112_7 simultaneously, the current of I1 is output to Iout. Finally, in the third transmission pulse, by turning on switches 112_3 and 112_5 simultaneously, the current of -I1 is output to Iout.

[0025] That is, when transmitting signal L, as shown in FIG. 4, switch 112_1 is operated in the order of OFF, ON, OFF states. Similarly hereinafter, switch 112_2 is operated in the order of OFF, OFF, OFF states. Switch 112_3 is operated in the order of ON, OFF, ON states. Switch 112_4 is operated in the order of ON, OFF, OFF states. Switch 112_5 is operated in the order of ON, OFF, ON states. Switch 112_6 is operated in the order of ON, OFF, OFF states. Switch 112_7 is operated in the order of OFF, ON, OFF states. Switch 112_8 is operated in the order of OFF, OFF, OFF states.

[0026] The current flowing through Iout is output in the order of -(I1 + I2), I1, -I1. The first transmission pulse, the second transmission pulse, and the third transmission pulse are output in proportion to the magnitude of the output of the current. That is, since the first transmission pulse is output based on a current with a large I2, it is larger than the third transmission pulse.

[0027] The control signal generation unit 120 generates a control signal for controlling the movement of the switches included in the transmission pulse generation circuit 110. The control signal generation unit 120 controls the operation of the switches of the transmission pulse generation circuit 110 from two types of signals, a data signal and a trigger signal.

[0028] The trigger signal is a signal indicating the timing at which the transmission pulse generation circuit 110 transmits a pulse. The trigger signal is a signal that can be discriminated as a high level or a low level. The control signal generation unit 120 transmits a pulse signal in response to the rising edge of the trigger signal.

[0029] The data signal is a signal indicating the type of signal output by the transmission pulse. Similar to the trigger signal, the data signal is a signal that can be discriminated between high level and low level. The control signal generation unit 120 controls the switch included in the transmission pulse generation circuit 110 so as to output a transmission pulse corresponding to the high level and low level of the data signal. In the present embodiment, if the data signal is at a high level, the control signal generation unit 120 transmits signal H. If the data signal is at a low level, the control signal generation unit 120 transmits signal L.

[0030] For example, as shown in FIG. 3, when the rising edge of the trigger signal is detected and the data signal indicates a high level, the transmission pulse generation circuit 110 transmits signal H. For example, when the rising edge of the trigger signal is detected and the data signal indicates a low level, the transmission pulse generation circuit 110 transmits signal L. The trigger signal and the data signal may be combined as an input signal that outputs an analog waveform (first waveform).

[0031] In the present embodiment, the transmission circuit 100 includes the transmission pulse generation circuit 110 and the control signal generation unit 120 integrally, but they may be provided separately. For example, the transmission circuit 100 outputs an analog waveform, and the transmission pulse generation circuit 110 and the control signal generation unit 120 may be provided respectively or one of them outside the transmission circuit 100.

[0032] FIG. 5 shows an example of the operation of the transmission circuit 100 transmitting an analog waveform. The control signal generation unit 120 determines whether it has received the rising edge of the trigger signal (S1001). If the trigger signal is received, it proceeds to S1002, and if not, the process ends.

[0033] The control signal generation unit 120 determines whether it has received a data signal (S1002). If it has received the data signal, it proceeds to S1003; if not, the process ends.

[0034] The control signal generation unit 120 determines the type of the received data signal (S1003). If it has received a high-level data signal, it proceeds to S1004; if it has received a low-level data signal, it proceeds to S1005.

[0035] If the received data signal is high-level, the control signal generation unit 120 controls the transmission pulse generation circuit 110 to output signal H (S1004). Similarly, if the received data signal is low-level, the control signal generation unit 120 controls the transmission pulse generation circuit 110 to output signal L (S1005).

[0036] FIG. 6 shows the structure of the insulating element 200. The insulating element 200 transmits the analog waveform transmitted from the transmission circuit 100 by electromagnetic field coupling. The insulating element 200 may also be referred to as a transmission unit. In that case, the insulating element 200 extracts a specific frequency band from the signal transmitted from the transmission circuit 100 (has band-pass characteristics). That is, the insulating element 200 functions as a filter that extracts a specific frequency band (has band-pass characteristics). The filter may also be referred to as a filter unit. As a result, the analog waveform transmitted from the transmission circuit 100 is deformed by the transmission of the insulating element 200. The insulating element 200 removes signals that are not the electrical signals to be transmitted included in the input signal, such as noise. The insulating element 200 includes a high-pass filter 210 and a low-pass filter 220.

[0037] The high-pass filter 210 is a filter that does not attenuate components with frequencies higher than the cut-off frequency and attenuates components with frequencies lower than the cut-off frequency. The low-pass filter 220 is a filter that does not attenuate components with frequencies lower than the cut-off frequency and attenuates components with frequencies higher than the cut-off frequency.

[0038] The high-pass filter 210 and the low-pass filter 220 function as a band-pass filter that extracts components in a specific frequency band when combined.

[0039] The insulating element 200 extracts components in a specific frequency band from the analog waveform output by the transmission circuit 100 by the high-pass filter 210 and the low-pass filter 220. For example, the cut-off frequency on the low-frequency side is greater than one-tenth of the reciprocal of the pulse width of the transmission pulse. The insulating element 200 outputs a received signal (second waveform), which is an analog waveform with the edges of the pulse emphasized, from the analog waveform of the transmission signal by the extraction. The received signal includes a received pulse corresponding to the transmission pulse included in the transmission signal. For example, it includes a first received pulse (first received pulse waveform) corresponding to the first transmission pulse.

[0040] In this embodiment, the insulating element 200 is configured by an insulating transformer as a band-pass filter, but it may be configured by other elements. For example, it may be configured by elements such as capacitors. The insulating element 200 may be connected to the receiving circuit 300 using an antenna.

[0041] The receiving circuit 300 receives an analog waveform. The receiving circuit 300 may also be referred to as a receiving unit. The analog waveform received by the receiving circuit 300 is a signal from which, for example, noise has been removed from the transmission signal by the insulating element 200. The receiving circuit 300 determines the high level and low level of the digital signal from the received pulse included in the received analog waveform and regenerates the input signal.

[0042] FIG. 7 shows the change in the pulse at a specific terminal when the cut-off frequency of the high-pass filter 210 is changed. FIG. 8 shows the change in the pulse when the amplitude of the first transmission pulse is amplified and transmitted in FIG. 6. FIG. 9 shows the change in the pulse when the cut-off frequency of the high-pass filter 210 is set to a specific frequency. In the transceiver circuit 1000, the analog waveform transmitted by the transmission circuit 100 passes through the high-pass filter 210, passes through the low-pass filter 220, and is then received by the receiving circuit 300.

[0043] When the pulse width is tpulse and the fundamental frequency f0 = 1 / tpulse, the waveforms in which the cut-off frequency (fc_hpf) of the high-pass filter 210 is changed in the range of 0.02f0 to f0 at each of the terminals A, B, and C in FIG. 6 are shown as in FIGS. 7 and 8. FIG. 7 shows the case where the magnitudes of the pulse waveforms included in the analog waveform are all the same, and FIG. 8 shows the case where the first transmission pulse is larger than the other transmission pulses among the pulse waveforms included in the analog waveform.

[0044] The waveform measured at terminal A in FIG. 6 is the analog waveform immediately after transmission from the transmission circuit 100, that is, the waveform measuring the transmission pulse. The waveform measured at terminal B in FIG. 6 is the analog waveform immediately after passing through the high-pass filter 210. The waveform measured at terminal C in FIG. 6 is the analog waveform immediately after passing through the low-pass filter 220, that is, the waveform measuring the reception pulse.

[0045] In the high-pass filter 210 and the low-pass filter 220 included in the insulating element 200, by selecting an appropriate cut-off frequency, the general shape of the reception pulse measured at terminal C is reproduced.

[0046] In the analog waveform measured at terminal B, the signal corresponding to the rising edge of the first transmission pulse becomes smaller than the signals corresponding to the edges of the second transmission pulse and the third transmission pulse. Similarly, in the analog waveform measured at terminal C, the signal corresponding to the rising edge of the first transmission pulse in the analog waveform measured at terminal B is smaller than the signals corresponding to the edges of the second and third transmission pulses.

[0047] When the magnitudes of all the pulse waveforms included in the analog waveform are the same, as shown in FIG. 7, in the analog waveform measured at terminal C, the signal corresponding to the rising edge of the first transmission pulse is smaller than the signals corresponding to the edges of the second and third transmission pulses. On the other hand, when the first transmission pulse among the pulse waveforms included in the analog waveform is larger than the other transmission pulses, as shown in FIG. 8, in the analog waveform measured at terminal C, the signal corresponding to the rising edge of the first transmission pulse in the analog waveform is of the same magnitude as the signals corresponding to the edges of the second and third transmission pulses.

[0048] The tendency of the signal corresponding to the rising edge of the first transmission pulse becomes more prominent as fc_hpf is higher. For example, when fc_hpf is about > 0.1f0, it becomes particularly smaller than the signals corresponding to the edges of the second and third transmission pulses.

[0049] Furthermore, in the received pulse included in the analog waveform measured at terminal C, the amplitude of the output waveform corresponding to the first received pulse becomes smaller.

[0050] The transceiver circuit 1000 receives the received pulse included in the analog waveform measured at terminal C by the receiving circuit 300. The transmitted pulse can be restored by reproducing the received pulse with a comparator or the like, and the input signal can be received.

[0051] That is, if the high level and low level of the first received pulse in the analog waveform measured at terminal C can be determined, the high level and low level of the second received pulse (second received pulse waveform) and the third received pulse can be determined, and it is possible to restore the transmitted pulse from the received pulse in the receiving circuit 300. That is, the reception performance of the transmission / reception circuit 1000 is determined based on the first received pulse, which is the pulse with the minimum amplitude among the received pulses corresponding to the transmission pulses.

[0052] The analog waveform at terminal C has signal energy proportional to the amplitude. Considering noise and the like with respect to the signal, the reception performance of the reception circuit 300 is limited by the pulse with the smallest signal energy, that is, the first received pulse.

[0053] By increasing the signal energy applied to the entire analog waveform measured at terminal C, that is, by increasing the energy of the signal transmitted by the transmission circuit 100, the amplitude of the first received pulse also increases, and the reception performance of the reception circuit 300 can be improved.

[0054] The power consumed by the transmission circuit 100 generally is proportional to the height of the pulse, or the square of the height. In this description, it is described assuming that the power consumption is proportional to the pulse amplitude. If the energy of the signal transmitted by the transmission circuit 100 increases, the power consumption increases proportionally.

[0055] In the transmission / reception circuit 1000 of this embodiment, the transmission circuit 100 increases the amplitude of the first transmission pulse. As a result, the amplitude of the analog waveform measured at terminal C corresponding to the first received pulse can be increased.

[0056] For example, as shown by the solid line in FIG. 9, when fc_hpf = 0.4f0, the amplitude of the first transmission pulse at terminal C is about 0.4 times that of the other pulses. Here, as shown by the dashed line in FIG. 9, when the amplitude of the first transmission pulse is tripled, the amplitude of the first received pulse at fc_hpf = 0.4f0 becomes about 0.8 times that of the third received pulse, and the amplitude of the received pulse corresponding to the transmission pulse increases.

[0057] That is, by tripling the first transmission pulse, the amplitude corresponding to the first received pulse that determines the reception performance is improved by about three times.

[0058] When simply tripling the first transmission pulse, since the amplitude of the first received pulse received by the receiving circuit 300 also becomes three times, the bottleneck of the receiving performance is eliminated.

[0059] FIG. 10 shows the relationship of current pulses compared with the total power consumption being constant. In FIG. 10, the horizontal axis indicates the doubling rate of the first transmission pulse, and the vertical axis indicates the pulse peak voltage of the received pulse. FIG. 10 shows the first received pulse with a one-dot chain line, the second received pulse with a chain line, and the third received pulse with a solid line. For example, when simply tripling the first transmission pulse, the power consumption of the transmission circuit 100 increases by 5 / 3 times. At this time, the transceiver circuit 1000 has lower power consumption compared to the case where all of the first to third transmission pulses are tripled.

[0060] The receiving performance of the transceiver circuit 1000 is determined by the magnitude of the smallest received pulse as described above. That is, in this embodiment, it is determined by the magnitude of the first received pulse which is the smallest. For example, when the power consumption of the transmission circuit 100 is constant, as the first transmission pulse increases, the other transmission pulses become smaller. For example, as shown in FIG. 10, even when the first transmission pulse is amplified three times, the smallest received pulse is the first received pulse in terms of the magnitude of the pulse peak voltage. That is, without increasing the consumed power, the transceiver circuit 1000 can improve the receiving performance by amplifying the first received pulse which is the smallest received pulse.

[0061] FIG. 11 shows the ratio of the first received pulse to the ratio of the first transmission pulse to the other transmission pulses based on the condition that the power consumption is constant when the power consumption is proportional to the pulse amplitude. FIG. 12 shows the ratio of the first received pulse to the ratio of the first transmission pulse to the other transmission pulses based on the condition that the power consumption is constant when the power consumption is proportional to the square of the pulse amplitude.

[0062] The minimum pulse amplitude that appears at terminal C varies depending on fc_hpf of the insulating element 200. As shown in FIG. 11, as the first transmission pulse of the insulating element 200 increases compared to other transmission pulses, the ratio of the first reception pulse increases. In FIG. 11, the ratio of the first reception pulse is represented based on the first reception pulse when the ratio of the first transmission pulse to other transmission pulses is 1. For example, when fc_hpf is at 0.3f0 and the ratio of the first transmission pulse to other transmission pulses is 1, the ratio of the magnitude of the first reception pulse is also 1. However, as the ratio of the first transmission pulse to other transmission pulses increases, that is, as the first transmission pulse becomes larger than other transmission pulses, the ratio of the first reception pulse also increases. The reception performance is improved by increasing the smallest first reception pulse.

[0063] In FIG. 11, the case where the power consumption is proportional to the pulse amplitude has been described. However, as shown in FIG. 12, the same tendency is shown even when the power consumption is proportional to the square of the pulse amplitude. Also in FIG. 12, the ratio of the first reception pulse is represented based on the first reception pulse when the ratio of the first transmission pulse to other transmission pulses is 1. For example, when fc_hpf is at 0.3f0 and the ratio of the first transmission pulse to other transmission pulses is 1, the ratio of the magnitude of the first reception pulse is also 1. However, as the ratio of the first transmission pulse to other transmission pulses increases, that is, as the first transmission pulse becomes larger than other transmission pulses, the ratio of the first reception pulse also increases. The reception performance is improved by increasing the smallest first reception pulse.

[0064] Thereby, by increasing the amplitude of the first transmission pulse, it is not necessary to increase the amplitudes of all the transmission pulses, and the reception performance of the transceiver circuit 1000 can be improved without increasing the power consumption of the transmission circuit 100.

[0065] (Modification Example 1) FIG. 13 shows the configuration of the transmission pulse generation circuit 2110 according to this modified example. FIG. 14 shows the ON and OFF states of the switch during signal transmission. In Modified Example 1, the transmission and reception circuit 2000 includes a transmission circuit 2100. Since the configuration of the transmission and reception circuit 2000 other than the transmission circuit 2100 remains unchanged from the transmission and reception circuit 1000, this part will be omitted. The transmission circuit 2100 includes a transmission pulse generation circuit 2110 and a control signal generation unit 120. The transmission pulse generation circuit 2110 generates a transmission pulse using a voltage pulse.

[0066] The transmission pulse generation circuit 2110 includes terminals 2111_1 and 2111_2 to which voltages V1 and V2 greater than V1 are applied, and switches 2112_1 to 2111_8. In this description, the case where there are eight switches is described, but other numbers are also possible. Similar to the switch 112, the switch 2112 may be a digital circuit such as a transistor or an integrated circuit (IC).

[0067] For example, when transmitting a signal H, in the first transmission pulse, by turning on switches 2112_2 and 2112_8 simultaneously, a voltage V2 is output to Vout. Next, in the second transmission pulse, by turning on switches 2112_3 and 2112_5 simultaneously, a voltage -V1 is output to Vout. Finally, in the third transmission pulse, by turning on switches 2112_1 and 2112_7 simultaneously, a voltage V1 is output to Vout.

[0068] That is, when transmitting a signal H, as shown in FIG. 14, the switch 2112_1 is operated in the order of OFF, OFF, and ON states. Similarly, operate switch 2112_2 in the order of ON, OFF, OFF states. Operate switch 2112_3 in the order of OFF, ON, OFF states. Operate switch 2112_4 in the order of OFF, OFF, OFF states. Operate switch 2112_5 in the order of OFF, ON, OFF states. Operate switch 2112_6 in the order of OFF, OFF, OFF states. Operate switch 2112_7 in the order of OFF, OFF, ON states. Operate switch 2112_8 in the order of ON, OFF, OFF states.

[0069] The voltages output to Vout are output in the order of V2, -V1, V1. The first transmission pulse, the second transmission pulse, and the third transmission pulse are output in proportion to the magnitude of the output of the voltage. That is, since the first transmission pulse is output based on a voltage V2 greater than V1, it is larger than the third transmission pulse.

[0070] For example, when transmitting signal L, in the first transmission pulse, by turning on switches 2112_4 and 2112_6 simultaneously, a voltage -V2 is output to Vout. Next, in the second transmission pulse, by turning on switches 2112_1 and 2112_7 simultaneously, a voltage V1 is output to Vout. Finally, in the third transmission pulse, by turning on switches 2112_3 and 2112_5 simultaneously, a voltage V1 is output to Vout.

[0071] That is, when transmitting signal L, as shown in FIG. 14, operate switch 2112_1 in the order of OFF, OFF, ON states. Similarly, operate the switches 2112_2 in the order of OFF, OFF, OFF. Operate the switches 2112_3 in the order of OFF, OFF, ON. Operate the switches 2112_4 in the order of ON, OFF, OFF. Operate the switches 2112_5 in the order of OFF, OFF, ON. Operate the switches 2112_6 in the order of ON, OFF, OFF. Operate the switches 2112_7 in the order of OFF, ON, OFF. Operate the switches 2112_8 in the order of OF, OFF, OFF.

[0072] The voltages output to Vout are output in the order of -V2, V1, -V1. The first transmission pulse, the second transmission pulse, and the third transmission pulse are output in proportion to the magnitude of the output of the voltage. That is, since the first transmission pulse is output based on the voltage V2 that is larger than V1, it is larger than the third transmission pulse.

[0073] According to Modification 1, the transmission pulse transmitted by the transmission circuit 2100 can be a pulse other than a current pulse, for example, a differential voltage can also be used.

[0074] (Modification 2) FIG. 15 shows the overall configuration of the transceiver circuit 3000 according to this modification. FIG. 16 shows the circuit configuration of the transmission pulse generation circuit 3110 according to this modification. FIG. 17 shows the transmission signal output by the combination of the trigger signal and the data signal. FIG. 18 shows the ON and OFF of the switches during signal transmission. In Modification 2, the transceiver circuit 3000 includes a transmission circuit 3100 and an insulating element 3200. Since the configuration of the transceiver circuit 3000 other than this part is not changed from the transceiver circuit 1000, this part will be omitted. The transmission pulse transmitted by the transmission circuit 3100 can be a pulse other than a differential current pulse, for example, a pseudo-differential current pulse can also be used. The transmission circuit 3100 includes a transmission pulse generation circuit 3110 that generates a transmission pulse based on a pseudo-differential current pulse, and a control signal generation unit 120.

[0075] The transmission pulse generation circuit 3110 can handle the case where Ioutp and Ioutn outputted for the pseudo differential configuration are not equal, for example, by connecting to an insulating element 3200 with a ground point connected to the midpoint. If the insulating element 3200 is to be connected to the ground point, it may be an element other than an insulating transformer, for example, a capacitor.

[0076] For example, as shown in FIG. 17, when detecting the rising edge of the trigger signal and at the timing when the data signal indicates a high level, the transmission pulse generation circuit 3110 transmits signal H. For example, when detecting the rising edge of the trigger signal and at the timing when the data signal indicates a low level, the transmission pulse generation circuit 3110 transmits signal L.

[0077] The transmission pulse generation circuit 3110 includes current sources 3111_1 to 3111_4 and switches 3112_1 to 3112_4. In this description, the case where there are four current sources and switches respectively is described, but other numbers may also be possible. The switch 3112 may be a digital circuit such as a transistor or an integrated circuit (IC), similar to the switch 112.

[0078] For example, when transmitting signal H, in the first transmission pulse, by turning on switches 3112_3 and 3112_4 simultaneously, a current I1 + I2 is output to Ioutp. Next, in the second transmission pulse, by turning on switch 3112_1, current I1 is output to Ioutn. Finally, in the third transmission pulse, by turning on switch 3112_3, current I1 is output to Ioutp.

[0079] That is, when transmitting signal H, as shown in FIG. 18, the switch 3112_1 is operated in the order of OFF, ON, OFF states. Similarly, operate the switch 3112_2 in the order of OFF, OFF, OFF states. Operate the switch 3112_3 in the order of ON, OFF, ON states. Operate the switch 3112_4 in the order of ON, OFF, OFF states.

[0080] The current flowing through Ioutp is output in the order of I1 + I2, no output, I1. The current flowing through Ioutn is output in the order of no output, I1, no output. The first transmission pulse and the third transmission pulse are output in proportion to the magnitude of the output of the current flowing through Ioutp. The second transmission pulse is output in proportion to the magnitude of the output of the current flowing through Ioutn. That is, since the first transmission pulse is output based on a larger current of I2, it is larger than the third transmission pulse.

[0081] For example, when transmitting the signal L, in the first transmission pulse, by turning on the switches 3112_1 and 3112_2 simultaneously, a current I1 + I2 is output to Ioutn. Next, in the second transmission pulse, by turning on the switch 3112_3, the current I1 is output to Ioutp. Finally, in the third transmission pulse, by turning on the switch 3112_1, the current I1 is output to Ioutn.

[0082] That is, when transmitting the signal L, as shown in FIG. 18, operate the switch 3112_1 in the order of ON, OFF, ON states. Similarly, operate the switch 3112_2 in the order of ON, OFF, OFF states. Operate the switch 3112_3 in the order of OFF, ON, OFF states. Operate the switch 3112_4 in the order of OFF, OFF, OFF states.

[0083] The current flowing through Ioutp is output in the order of no output, I1, no output. The current flowing through Ioutn is output in the order of I1 + I2, no output, I1. The first transmission pulse and the third transmission pulse are output in proportion to the magnitude of the output of the current flowing through Ioutn. The second transmission pulse is output in proportion to the magnitude of the output of the current flowing through Ioutp. That is, since the first transmission pulse is output based on a large current of I2, it becomes larger than the third transmission pulse.

[0084] According to Modification 2, as the transmission pulse transmitted by the transmission circuit, a current pulse based on a pseudo differential current can also be used.

[0085] (Modification 3) FIG. 19 shows the structure of the transmission pulse generation circuit 4110 according to this modification. FIG. 20 shows the ON and OFF states of the switch during signal transmission. In Modification 3, the transmission and reception circuit 4000 includes a transmission circuit 4100. Since the configuration of the transmission and reception circuit 4000 other than this part is not changed from the transmission and reception circuit 3000, this part will be omitted. This part is, for example, a transmission signal output by a combination of the trigger signal and the data signal shown in FIG. 17.

[0086] As the transmission pulse transmitted by the transmission circuit 4100, a pseudo differential voltage pulse can also be used. The transmission circuit 4100 includes a transmission pulse generation circuit 4110 that generates a transmission pulse based on a pseudo differential voltage pulse, and a control signal generation unit 120.

[0087] The transmission pulse generation circuit 4110 can handle the case where Voutp and Voutn output for the pseudo differential configuration are not equal, for example, by connecting to an insulating element 3200 with a ground point connected to the midpoint.

[0088] For example, as shown in FIG. 17, when detecting the rising edge of the trigger signal and at the timing when the data signal indicates a high level, the transmission pulse generation circuit 4110 transmits signal H. For example, when detecting the rising edge of the trigger signal and at the timing when the data signal indicates a low level, the transmission pulse generation circuit 4110 transmits signal L.

[0089] The transmission pulse generation circuit 4110 includes terminals 4111_1 and 4111_2 to which voltages V1 and V2 greater than V1 are applied, and switches 4112_1 to 4111_6. In this description, the case where there are six switches is described, but the number may be other than six. Similar to the switch 112, the switch 4112 may be a digital circuit such as a transistor or an integrated circuit (IC).

[0090] For example, when transmitting a signal H, in the first transmission pulse, by turning on switches 4112_2 and 4112_6 simultaneously, a voltage V2 is output to Voutp. Next, in the second transmission pulse, by turning on switches 4112_3 and 4112_5 simultaneously, a voltage V1 is output to Voutn. Finally, in the third transmission pulse, by turning on switches 4112_1 and 4112_6 simultaneously, a voltage V1 is output to Voutp.

[0091] That is, when transmitting a signal H, as shown in FIG. 20, the switch 4112_1 is operated in the order of OFF, OFF, ON. Similarly hereinafter, the switch 4112_2 is operated in the order of ON, OFF, OFF. The switch 4112_3 is operated in the order of OFF, ON, OFF. The switch 4112_4 is operated in the order of OFF, OFF, OFF. The switch 4112_5 is operated in the order of OFF, ON, OFF. The switch 4112_6 is operated in the order of ON, OFF, ON.

[0092] The voltages output to Voutp are output in the order of V2, no output, V1. The currents flowing through Voutn are output in the order of no output, V1, no output. The first transmission pulse and the third transmission pulse are output in proportion to the magnitude of the output of the voltage to Voutp. The second transmission pulse is output in proportion to the magnitude of the output of the voltage to Voutn. That is, since the first transmission pulse is output based on the voltage V2 that is higher than V1, it becomes larger than the third transmission pulse.

[0093] According to Modification 3, the transmission pulse transmitted by the transmission circuit 4100 can also use a pseudo differential voltage.

[0094] (Modification 4) FIG. 21 shows the structure of the transmission pulse generation circuit 5110 according to this modification. In Modification 4, the transmission and reception circuit 5000 includes a transmission circuit 5100. Since the configuration other than the transmission pulse generation circuit 5110 of the transmission and reception circuit 5000 is not changed from the transmission and reception circuit 1000, this part will be omitted. The transmission pulse generation circuit 5110 can change the magnification n for increasing the amplitude of the first transmission pulse. The optimal amplitude of the first transmission pulse is greatly affected by the filter characteristics of the path through which the signal is transmitted. The insulating element 200 connected to the transmission pulse generation circuit 5110 functions as a band-pass filter, and its characteristics can be predicted in advance.

[0095] However, due to variations during manufacturing or significant fluctuations in the filter characteristics due to the ambient temperature and environment in which the insulating element 200 is used, there may be cases. In such a case, it is difficult to predict in advance the filter characteristics in which the insulating element 200 functions as a band-pass filter.

[0096] The transmission pulse generation circuit 5110 can increase the amplitude of the first transmission pulse to an optimal value regardless of the filter characteristics by changing the magnification n of the amplitude increase of the first transmission pulse associated with the varying filter characteristics.

[0097] The transmission pulse generation circuit 5110 includes current sources 5111_1, 5111_3, 5111_5, 5111_7 that each pass a current of I1, current sources 5111_2, 5111_4, 5111_6, 5111_8 that each pass a current of at least one or more multiple (M) of I2, and switches 5112_1 to 5112_8 connected to the respective current sources. Similar to switch 112, switch 5112 may be a digital circuit such as a transistor or an integrated circuit (IC), for example.

[0098] Switches 5112_1 to 5112_8 are respectively connected to current sources 5111_1 to 5111_8 and output a current when turned ON.

[0099] The current sources 5111_2, 5111_4, 5111_6, 4111_8 that each pass a current of M of I2 can change the value of the flowing current by adjusting the number of switches turned ON.

[0100] By thus selecting, according to the characteristics of the transmission path, how many times to multiply the amplitude of the first transmission pulse relative to other pulses, the amplitude of the first transmission pulse can be increased at an appropriate magnification n regardless of the characteristics of the transmission path.

[0101] (Modification 5) FIG. 22 shows the overall configuration of the transmission and reception circuit 6000 according to this modification. FIG. 23 shows the transmission signal output by combination with the data signal. In Modification 5, the transmission and reception circuit 6000 includes a transmission circuit 6100. Since the configuration other than the transmission circuit 6100 in the transmission and reception circuit 6000 is not changed from the transmission and reception circuit 1000, this part will be omitted. The transmission circuit 6100 includes a transmission pulse generation circuit 110 and a control signal generation unit 6120. The control signal generation unit 6120 generates a control signal that controls the movement of the switches included in the transmission pulse generation circuit 110. Specifically, the control signal generation unit 6120 controls the operation of the switches of the transmission pulse generation circuit 110 from the data signal.

[0102] The data signal is a signal indicating the type of signal output by the transmission pulse. The data signal is a signal that can be discriminated as a high level or a low level. The control signal generation unit 5120 controls the switch included in the transmission pulse generation circuit 110 so as to output a transmission pulse according to the change between the high level and the low level of the data signal. In this modification, if the rising edge of the data signal is detected, the control signal generation unit 120 transmits signal H. If the falling edge of the data signal is detected, the control signal generation unit 120 transmits signal L. The data signal may be an input signal that outputs an analog waveform (first waveform) due to the transition of the data signal.

[0103] According to Modification 5, the control signal generation unit 6120 can control signal transmission and reception with the data signal.

[0104] (Modification 6) FIG. 24 shows the overall configuration of the transmission / reception circuit 7000 according to this modification. FIG. 25 shows a transmission signal output by combination with a data signal. The transmission circuit 7100 of the transmission / reception circuit 7000 includes a transmission pulse generation circuit 3110 and a control signal generation unit 5120. The control signal generation unit 5120 that controls the operation of the switch of the transmission pulse generation circuit 110 from the data signal can be combined with the transmission pulse generation circuit 3110 using a pseudo current pulse.

[0105] In this modification, as shown in FIG. 25, if the rising edge of the data signal is detected, the control signal generation unit 5120 transmits signal H by transmitting a predetermined pulse from Ioutp and Ioutn. If the falling edge of the data signal is detected, the control signal generation unit 5120 transmits signal L by transmitting a predetermined pulse from Ioutp and Ioutn.

[0106] (Modification 7) FIG. 26 shows the overall configuration of the transmission / reception circuit 8000 according to this modified example. The transmission / reception circuit 8000 includes a transmission circuit 8100, an insulating element 200, a reception circuit 300, and an AD conversion circuit 400. The transmission circuit 8100 includes a transmission pulse generation circuit 110 and a control signal generation unit 8120. The transmission / reception circuit 8000 is a transmission / reception circuit in which the input signal is an analog input signal. The transmission / reception circuit 7000 operates as an isolation amplifier that insulates and transmits an analog signal.

[0107] The AD conversion circuit 400 is a conversion circuit that converts an analog input signal into a digital input signal. The AD conversion circuit 400 may also be referred to as an AD conversion unit. The AD conversion circuit 400 is also called an analog-digital conversion circuit, and a flash ADC, a pipeline ADC, a ΔΣ modulator, etc. can be used.

[0108] A CLK signal (clock signal) is input to the AD conversion circuit 400 and the control signal generation unit 7120. The AD conversion circuit 400 converts an analog input signal into a digital signal based on the timing of the CLK signal and outputs it as a data signal.

[0109] The control signal generation unit 8120 captures a data signal at a timing when the output of the AD conversion circuit 400 does not change based on the CLK signal, and generates a control signal to the transmission pulse generation circuit 110. For example, when the output signal of the AD conversion circuit 400 changes at the rising edge of the CLK signal, the control signal generation unit 7120 captures the data signal at the falling edge and generates a control signal.

[0110] According to Modified Example 7, an analog signal can be converted into a digital signal as an input signal and transmitted to the reception circuit 300.

[0111] (Modified Example 8) FIG. 27 shows the change in the pulse at a specific terminal when the cut-off frequency of the high-pass filter 210 is changed when the number of pulse waveforms is 2. FIG. 28 shows the change in the pulse when the amplitude of the first transmission pulse is amplified and transmitted in FIG. 27.

[0112] The transceiver circuit 1000 can set the number N of pulse waveforms transmitted by the transmission circuit 100 to other than 3. For example, when the transceiver circuit 1000 sets the number N of pulse waveforms to 2, the transmission circuit 100 transmits the input signal as an analog waveform of two consecutive pulse waveforms. For example, the analog waveform can be regarded as a digital signal represented by two bits.

[0113] In this description, among the two pulses output by the transmission circuit 100, the first output pulse is defined as the first transmission pulse, and the next output pulse is defined as the second transmission pulse.

[0114] The waveforms obtained by changing the cut-off frequency (fc_hpf) of the high-pass filter 210 in the range of 0.02f0 to f0 at each of the terminals A, B, and C in FIG. 6 are shown as in FIG. 27.

[0115] Similar to the case where the number N of pulse waveforms is 3, at the insulating element 200, by selecting an appropriate cut-off frequency, the general shape of the received pulse measured at terminal C can be reproduced from the waveforms measured at terminal A, terminal B, and terminal C in FIG. 6.

[0116] In the analog waveform measured at terminal B, the signal corresponding to the rising edge of the first transmission pulse is smaller than the signal corresponding to the edge of the second transmission pulse. Similarly, in the analog waveform measured at terminal C, the signal corresponding to the rising edge of the first transmission pulse in the analog waveform measured at terminal B is smaller than the signal corresponding to the edge of the second transmission pulse.

[0117] The tendency of the signal corresponding to the rising edge of the first transmission pulse becomes more prominent as fc_hpf is higher, similar to the case where the number N of pulse waveforms is 3. For example, when fc_hpf is about > 0.1f0, it becomes particularly smaller than the signal corresponding to the edge of the second transmission pulse. Furthermore, for the received pulse included in the analog waveform measured at terminal C, the amplitude of the output waveform corresponding to the first received pulse becomes smaller.

[0118] That is, even when the number N of pulse waveforms is 2, if the high level and low level of the first received pulse of the analog waveform measured at terminal C can be determined, the high level and low level of the second received pulse (second received pulse waveform) can be determined, and it is possible to restore the transmission pulse from the received pulse in the receiving circuit 300. That is, the reception performance of the transmission / reception circuit 1000 is determined based on the first received pulse, which is the pulse with the minimum amplitude among the received pulses corresponding to the transmission pulse.

[0119] FIG. 29 shows the ratio of the first received pulse to the ratio of the first transmission pulse and the second transmission pulse based on the condition that the power consumption is constant when the power consumption is proportional to the pulse amplitude. FIG. 30 shows the ratio of the first received pulse to the ratio of the first transmission pulse and the second transmission pulse based on the condition that the power consumption is constant when the power consumption is proportional to the square of the pulse amplitude.

[0120] The minimum pulse amplitude that appears at terminal C, that is, the second received pulse, does not change significantly due to fc_hpf of the insulating element 200. As shown in FIG. 29, as the first transmission pulse of the insulating element 200 increases more than the second transmission pulse, the ratio of the first received pulse increases. In FIG. 29, the ratio of the first received pulse is represented based on the first received pulse when the ratio of the first transmission pulse and the second transmission pulse is 1. For example, as shown in FIG. 29, when the first transmission pulse is transmitted at a magnitude 1.5 times or more greater than the second transmission pulse, the ratio of the first reception pulse becomes about 1.2 times or more greater. That is, as the first transmission pulse becomes greater than the second transmission pulse, the ratio of the first reception pulse also increases. The reception performance is improved by the increase in the smallest first reception pulse.

[0121] The fc_hpf of the insulating element 200 shows the same result in any case, and in FIG. 29, the graphs are shown overlapping.

[0122] The same tendency is shown even when the transmission energy is proportional to the square of the pulse amplitude. Also in FIG. 30, the ratio of the first reception pulse is represented with reference to the first reception pulse when the ratio of the first transmission pulse to the second transmission pulse is 1. For example, as shown in FIG. 30, when the first transmission pulse is transmitted at a magnitude 1.5 times or more greater than the second transmission pulse, the ratio of the first reception pulse becomes about 1.2 times or more greater. That is, as the first transmission pulse becomes greater than the second transmission pulse, the ratio of the first reception pulse also increases. The reception performance is improved by the increase in the smallest first reception pulse.

[0123] The fc_hpf of the insulating element 200 shows the same result in any case, and in FIG. 30, as in FIG. 29, the graphs are shown overlapping.

[0124] (Modification Example 9) FIG. 31 shows the overall configuration of the transmission / reception circuit 9000 according to this modification example. In Modification Example 9, the transmission / reception circuit 9000 includes an insulating element 9200 and a reception circuit 9300. Since the configuration of the transmission / reception circuit 9000 other than this part is not changed from the transmission / reception circuit 1000, this part will be omitted.

[0125] The insulating element 9200 transmits the analog waveform transmitted from the transmission circuit 100 by electromagnetic field coupling. At this time, the insulating element 9200 functions as a bypass filter that extracts a specific frequency band from the signal transmitted from the transmission circuit 100 (band-pass characteristic). As a result, the analog waveform transmitted from the transmission circuit 100 is deformed.

[0126] Due to the characteristics of the insulating element 9200 as a high-pass filter, it emphasizes the components of the frequency corresponding to the pulse width and outputs an analog waveform (second waveform). The analog waveform in which the insulating element 9200 emphasizes the frequency components includes signals that are not electrical signals to be amplified, such as noise.

[0127] For example, when the transmission circuit 100 outputs an analog waveform including two pulses, the analog waveform output by the insulating element 9200 includes a first received pulse based on the first transmission pulse and a second received pulse based on the second transmission pulse. The analog waveform output by the insulating element 9200 further includes a third received pulse, which is an enhanced pulse waveform based on the fact that the first transmission pulse and the second transmission pulse have their frequency components enhanced by the insulating element 200.

[0128] The insulating element 9200 outputs an analog waveform including three pulse waveforms to the receiving circuit 300. That is, the insulating element 9200 outputs an analog waveform including a larger number of pulse waveforms than the two pulse waveforms included in the analog waveform output by the transmission circuit 100.

[0129] The receiving circuit 9300 receives the analog waveform output by the insulating element 9200 and determines a signal based on the pulse waveforms included in the analog waveform.

[0130] That is, when the number of pulse waveforms included in the analog waveform is N, the receiving circuit 9300 determines the signal based on at least N + 1 pulse waveforms.

[0131] According to Modification 9, a signal can be received by an analog waveform including a larger number of pulse waveforms than the analog waveform including the pulse waveform output by the transmission circuit 100. That is, the transceiver circuit 9000 can transmit signals with low power consumption. Also, the transceiver circuit 9000 can transmit signals that are resistant to noise and interference.

[0132] Note that the present invention is not limited to the above-described embodiments as they are. At the implementation stage, the components can be modified and embodied without departing from the gist thereof. Also, various inventions can be formed by appropriately combining a plurality of components disclosed in the above-described embodiments. For example, some components may be deleted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined.

Explanation of Reference Numerals

[0133] 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000 Transceiver circuit 100, 2100, 3100, 5100, 6100, 7100 Transmitter circuit 110,, 2110, 3110, 4110, 7110 Transmission pulse generation circuit 120, 6120, 8120 Control signal generation unit 111, 3111, 5111 Current source 112, 2112, 3112, 4112 Switch 200, 3200, 9200 Insulating element 210 High-pass filter 220 Low-pass filter 2111 Terminal 300, 9300 Receiver circuit 400 AD conversion circuit

Claims

1. A transmission pulse generation unit that generates a plurality of pulse waveforms in response to an input signal, A transmission unit that transmits a waveform including the plurality of pulse waveforms to a reception circuit via an insulating element, comprising The pulse waveform includes a first transmission pulse waveform and a second transmission pulse waveform behind the first transmission pulse waveform, and the amplitude of the first transmission pulse waveform is larger than that of the second transmission pulse waveform. The transmission pulse generation unit has a plurality of first current sources each having a first switch and a plurality of second current sources each having a second switch, and by opening and closing the first switch and the second switch in a predetermined order when the input signal is input, first generates the first transmission pulse waveform, and subsequently generates the second transmission pulse waveform. A transmission circuit.

2. The magnitude of the amplitude of the first transmission pulse waveform is determined by the number of times the second switch opens and closes. The transmission circuit according to claim 1.

3. The output of the second current source is twice the output of the first current source. The transmission circuit according to claim 1.

4. Further comprising a control signal generation unit that controls the output of the transmission pulse generation unit based on a trigger signal indicating the output timing of the pulse waveform and a data signal indicating the polarity of the output pulse waveform. The transmission circuit according to any one of claims 1 to 3.

5. The pulse waveform is a current pulse and is output based on a differential current or a pseudo-differential current. The transmission circuit according to any one of claims 1 to 4.

6. The pulse waveform is a voltage pulse and is output based on a differential voltage or a pseudo-differential voltage. The transmission circuit according to any one of claims 1 to 4.

7. The transmission unit outputs the pulse waveform as a first waveform that is an analog waveform, The first waveform includes at least two of the pulse waveforms, The transmission circuit according to any one of claims 1 to 6.

8. Further comprising an AD conversion unit that converts an analog input signal into a digital input signal, The AD conversion unit outputs the digital input signal based on the timing of a clock signal, The transmission unit captures the digital input signal at a timing when the output of the AD conversion unit does not change based on the timing of the clock signal, and transmits the pulse waveform. The transmission circuit according to any one of claims 1 to 7.

9. The amplitude of the first transmission pulse waveform is three times the amplitude of the second transmission pulse waveform, The transmission circuit according to any one of claims 1 to 8.

10. The data signal is a digital signal having a high level and a low level, The transmission circuit according to claim 4.

11. The first transmission pulse waveform is the first output generated when the input signal is received, and the second transmission pulse waveform is the next output generated immediately following the first transmission pulse waveform, The transmission circuit according to any one of claims 1 to 10.

12. A transmission pulse generation unit that generates a plurality of pulse waveforms in response to an input signal, A transmission unit that outputs a first waveform including the plurality of pulse waveforms, A transmission unit that transmits the first waveform by electromagnetic field coupling and outputs it as a second waveform, The pulse waveform includes a first transmission pulse waveform and a second transmission pulse waveform following the first transmission pulse waveform. The amplitude of the first transmission pulse waveform is larger than that of the second transmission pulse waveform. The second waveform includes a first reception pulse waveform based on the first transmission pulse waveform and a second reception pulse waveform based on the second transmission pulse waveform. The transmission pulse generation unit includes a plurality of first current sources each having a first switch, and a plurality of second current sources each having a second switch. When the input signal is input, the first switch and the second switch are opened and closed in a predetermined order to first generate the first transmission pulse waveform and then generate the second transmission pulse waveform. Electronic circuit.

13. The transmission unit has high-pass filter characteristics. The electronic circuit according to claim 12.

14. The transmission unit has low-pass filter characteristics. The electronic circuit according to claim 12.

15. The cut-off frequency on the low-frequency side of the transmission unit is greater than one-tenth of the reciprocal of the pulse width of the first waveform. The electronic circuit according to claim 12.

16. The transmission unit is an insulating element. The electronic circuit according to any one of claims 12 to 15.

17. The insulating element is an insulator or a capacitor. The electronic circuit according to claim 16.

18. The first transmission pulse waveform is the output first generated when the input signal is received, and the second transmission pulse waveform is the next output generated immediately following the first transmission pulse waveform. The electronic circuit according to any one of claims 12 to 17.

19. A transmission pulse generation unit that generates a plurality of pulse waveforms in response to an input signal, A transmission unit that outputs a first waveform including the plurality of pulse waveforms; A transmission unit that transmits the first waveform by electromagnetic field coupling and outputs it as a second waveform; The pulse waveform includes a first transmission pulse waveform and a second transmission pulse waveform behind the first transmission pulse waveform. The amplitude of the first transmission pulse waveform is larger than that of the second transmission pulse waveform. The second waveform includes a first reception pulse waveform based on the first transmission pulse waveform and a second reception pulse waveform based on the second transmission pulse waveform. The transmission pulse generation unit includes a plurality of first current sources each having a first switch, and a plurality of second current sources each having a second switch. When the input signal is input, the first switch and the second switch are opened and closed in a predetermined order to first generate the first transmission pulse waveform, and then continue to generate the second transmission pulse waveform. A transceiver circuit.

20. Further comprising an AD conversion unit that converts an analog input signal into a digital input signal; The AD conversion unit outputs the digital input signal based on the transmission timing of the clock signal; The transmission unit captures the digital input signal at a timing when the output of the AD conversion unit does not change based on the clock signal, and transmits the pulse waveform. The transceiver circuit according to claim 19.

21. The transmission unit emphasizes the frequency components of the first waveform and outputs the second waveform; The second waveform includes at least one or more more pulse waveforms than the pulse waveforms included in the first waveform due to the emphasis of the frequency components. The transceiver circuit according to claim 19 or 20.

22. The first transmission pulse waveform is the output first generated when the input signal is received, and the second transmission pulse waveform is the next output generated immediately following the first transmission pulse waveform. The transmission and reception circuit according to any one of claims 19 to 21.

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