JP7801331B2 - Drive circuit and solid-state image sensor - Google Patents

Description

This technology relates to drive circuits. More specifically, it relates to drive circuits that transmit differential signals or single-phase signals, and solid-state imaging devices.

Conventionally, in interfaces such as MIPI (Mobile Industry Processor Interface), a driver such as a differential driver is placed in the circuit on the transmitting side. The greater the output capacitance of this circuit, the longer the rise and fall times of the transmitted signal, resulting in a decrease in transmission speed. Therefore, to shorten the rise and fall times, electronic components have been proposed in which a coil is inserted into the transmission path on the output side of the differential driver (see, for example, Patent Document 1).

Patent No. 5872710

The above-mentioned conventional technology aims to improve transmission speed by inserting a coil. However, if the coil's inductance is high, the rise and fall times become steep, making it difficult to suppress noise caused by EMI (Electro Magnetic Interference). As such, it is difficult to achieve both improved transmission speed and noise suppression with the above-mentioned electronic components.

This technology was developed in light of these circumstances, and aims to achieve both improved transmission speed and noise suppression in circuits in which drivers are placed.

This technology has been developed to solve the above-mentioned problems, and its first aspect comprises a transformer having multiple magnetically coupled coils and a driver that supplies either a non-differential signal or a differential signal to the transformer, where the multiple coils include magnetically coupled first and second coils, and the driver is connected to one end of the first coil and one end of the second coil, such that when a common-mode current is applied to the one end of each of the first and second coils, the magnetic fluxes generated by the first and second coils weaken each other. This reduces inductance during non-differential signal transmission.

Also, in this first aspect, the drive unit may supply the differential signal to one end of the first coil and one end of the second coil, and the drive unit may supply the differential signal to one end of the first coil and one end of the second coil. This results in the effect of transmitting a signal via two wires.

In addition, in this first aspect, a first ESD protection diode connected to a node between both ends of the first coil and a second ESD protection diode connected to a node between both ends of the second coil may be further provided. This has the effect of improving the waveform.

In addition, in this first aspect, the drive unit may include a shared driver that supplies either the differential signal or the non-differential signal, and an output voltage control unit that controls the output voltage of the shared driver. This reduces the number of drivers.

Furthermore, in this first aspect, the drive unit may be arranged on a specific semiconductor chip, and the transformer may be arranged outside the semiconductor chip. This has the effect of reducing the circuit scale of the semiconductor chip.

In addition, in this first aspect, the drive unit may include a differential driver that supplies the differential signal and a non-differential driver that supplies the non-differential signal. This eliminates the need to control the output voltage of the driver.

In addition, in this first aspect, the output terminal of the non-differential driver may be connected to a node between both ends of either the first or second coil, thereby eliminating the need for a connection to a center tap.

In addition, in this first aspect, the output terminal of the non-differential driver may be connected to one end of either the first or second coil, thereby improving the waveform.

Furthermore, in this first aspect, the drive unit may be arranged on a specific semiconductor chip, and the transformer may be arranged outside the semiconductor chip. This has the effect of reducing the circuit scale of the semiconductor chip.

Also, in this first aspect, the multiple coils may include magnetically coupled first, second, and third coils, and the drive unit may supply the differential signal to one end of the first coil, one end of the second coil, and one end of the third coil, such that when a common-mode current flows into the one end of each of the second and third coils, the magnetic fluxes generated by the second and third coils weaken each other. This results in the effect of transmitting signals via three wires.

Also, in this first aspect, the device may further include a receiver that receives a differential signal via first and second signal lines, and the driver may have first and second output terminals, one end of the first coil connected to the first output terminal and the other end connected to the first signal line, and one end of the second coil connected to the second output terminal and the other end connected to the second signal line. This results in the differential signal from the driver being input to the receiver via the first and second coils.

In addition, in this first aspect, the first and second coils may share a predetermined winding axis, and when viewed from the direction of the winding axis, the winding direction around the winding axis from one end of the first coil connected to the wiring output terminal to the other end connected to the signal line may be opposite to the winding direction around the winding axis from one end of the second coil connected to the wiring output terminal to the other end connected to the signal line. This results in the effect that when in-phase currents are applied to the end connected to the drive of the first coil and the end connected to the drive unit of the second coil, the magnetic fluxes generated by each coil weaken each other.

A second aspect of the present technology is a solid-state imaging device comprising: a transformer having multiple magnetically coupled coils; a driver that supplies either a non-differential signal or a differential signal to the transformer in accordance with a predetermined control signal; and a logic circuit that, in accordance with the control signal, specifies either the non-differential signal or the differential signal and causes the driver to supply the signal; the multiple coils include magnetically coupled first and second coils; the driver is connected to one end of the first coil and one end of the second coil; and when a common-mode current is applied to the one end of each of the first and second coils, the magnetic fluxes generated by the first and second coils weaken each other. This reduces the inductance to the non-differential signal when the logic circuit transmits the non-differential signal.

1 is a block diagram illustrating an example of a configuration of an imaging device according to a first embodiment of the present technology. 1 is a block diagram showing a configuration example of a solid-state imaging element according to a first embodiment of the present technology; 1 is a circuit diagram showing a configuration example of a drive circuit according to a first embodiment of the present technology; FIG. 2 is a plan view showing a winding direction of a coil according to the first embodiment of the present technology; FIG. 10 is a circuit diagram showing a configuration example of a drive circuit in a comparative example. 10A and 10B are diagrams for comparing inductance between the first embodiment of the present technology and a comparative example. 10 is a timing chart showing an example of the operation of the drive circuit according to the first embodiment of the present technology and a comparative example; FIG. 10 is a circuit diagram showing a configuration example of a drive circuit according to a second embodiment of the present technology. FIG. 11 is a circuit diagram showing a configuration example of a drive circuit according to a third embodiment of the present technology. FIG. 13 is a circuit diagram showing a configuration example of a drive circuit according to a fourth embodiment of the present technology. FIG. 13 is a circuit diagram showing a configuration example of a drive circuit according to a fifth embodiment of the present technology. FIG. 20 is a circuit diagram showing a configuration example of a drive circuit according to a sixth embodiment of the present technology. FIG. 23 is a circuit diagram showing a configuration example of a drive circuit according to a seventh embodiment of the present technology. FIG. 20 is a circuit diagram showing a configuration example of a drive circuit according to an eighth embodiment of the present technology. FIG. 23 is a circuit diagram showing a configuration example of a drive circuit according to a ninth embodiment of the present technology. 1 is a block diagram illustrating a schematic configuration example of a vehicle control system. FIG. 2 is an explanatory diagram showing an example of an installation position of an imaging unit.

Hereinafter, modes for carrying out the present technology (hereinafter referred to as embodiments) will be described in the following order.
1. First embodiment (example in which two magnetically coupled coils are provided)
2. Second embodiment (example in which two magnetically coupled coils are provided and a driver is connected to the center tap)
3. Third embodiment (example in which two magnetically coupled coils are provided and a diode is connected)
4. Fourth embodiment (example in which a driver is shared and two magnetically coupled coils are provided)
5. Fifth embodiment (example in which two magnetically coupled coils are arranged outside the chip)
6. Sixth embodiment (example in which the third embodiment is applied to the second embodiment)
7. Seventh embodiment (example in which the fourth embodiment is applied to the third embodiment)
8. Eighth embodiment (example in which the fifth embodiment is applied to the fourth embodiment)
9. Ninth embodiment (example in which three magnetically coupled coils are provided)
10. Mobile application examples

1. First embodiment
[Configuration example of imaging device]
1 is a block diagram showing an example configuration of an imaging device 100 according to a first embodiment of the present technology. The imaging device 100 is a device for capturing image data, and includes a solid-state imaging element 200 and a receiving unit 130 provided on a mounting substrate 110.

The solid-state imaging element 200 generates image data through photoelectric conversion. This solid-state imaging element 200 supplies the image data to the receiving unit 130 via the transmission path 120 on the mounting substrate 110. For example, MIPI is used as the standard for the communication interface between the solid-state imaging element 200 and the receiving unit 130. Note that communication interfaces other than MIPI can also be used.

The receiving unit 130 receives image data and performs predetermined image processing on the image data. For example, an application processor is used as this receiving unit 130. Image processing such as image recognition processing is performed.

[Configuration example of solid-state imaging device]
2 is a block diagram showing an example of the configuration of a solid-state imaging device 200 according to the first embodiment of the present technology. This solid-state imaging device 200 includes a pixel chip 201 and a circuit chip 202 that are stacked. These chips are electrically connected via connecting portions such as vias. Note that, in addition to vias, they can also be connected by Cu-Cu bonding or bumps. Connections can also be made by other methods (such as magnetic coupling). Furthermore, although two chips are stacked, three or more layers can also be stacked.

The pixel chip 201 has multiple pixels 210 arranged in a two-dimensional grid pattern. Furthermore, vertical signal lines 219 are wired to the pixel chip 201 for each column of pixels 210. The pixels 210 generate analog pixel signals using photoelectric conversion elements. These pixels 210 supply pixel signals to the circuit chip 202 via the vertical signal lines 219.

The circuit chip 202 includes an analog-to-digital conversion unit 220, a logic circuit 230, a serializer 240, and a drive circuit 300. The analog-to-digital conversion unit 220 performs AD (Analog to Digital) conversion on each pixel signal. The analog-to-digital conversion unit 220 has, for example, an ADC (Analog to Digital Converter) arranged for each column, which converts the analog pixel signal into a digital signal for each column. The analog-to-digital conversion unit 220 supplies the digital signal for each pixel to the logic circuit 230.

The logic circuit 230 performs predetermined signal processing on the digital signal. This signal processing includes CDS (Correlated Double Sampling) processing. The logic circuit 230 outputs the processed digital signal in parallel to the serializer 240.

The logic circuit 230 also supplies control signals DIF and SC to the drive circuit 300. These control signals are signals for controlling the drive circuit 300 to either a differential signal output state or a non-differential signal output state.

The differential signal output state is an operating state in which the drive circuit 300 supplies differential signals. The non-differential signal output state is an operating state in which the drive circuit 300 supplies a pair of signals that undergo either an in-phase transition or a single-phase transition. An in-phase transition means that both of the pair of signals simultaneously transition to a high level or a low level. A single-phase transition means that only one of the pair of signals transitions to a high level or a low level. Hereinafter, a signal that undergoes an in-phase transition will be referred to as an "in-phase signal," and a signal that undergoes a single-phase transition will be referred to as a "single-phase signal." In addition, in-phase signals and single-phase signals will be collectively referred to as "non-differential signals." Note that in the non-differential signal output state, the drive circuit 300 supplies both a single-phase signal and an in-phase signal, but it can also supply only one of them.

The serializer 240 performs parallel-to-serial conversion on the digital signal from the logic circuit 230. This serializer 240 sequentially supplies the digital signal after parallel-to-serial conversion to the drive circuit 300 one bit at a time via signal lines 241 to 244. A differential signal, an in-phase signal, or a single-phase signal is supplied under the control of the logic circuit 230. Two of these four signal lines are used to transmit differential signals, and the remaining two are used to transmit non-differential signals (in-phase signals or single-phase signals). The transmission speed of the differential signal from the serializer 240 is faster than that of the non-differential signal.

The driver circuit 300 adjusts the amplitude, fall time, and rise time of the digital signal from the serializer 240 to drive the transmission path 120 and the receiving circuit. The technique for adjusting the fall time and rise time is called peaking. The driver circuit 300 supplies the peaked digital signal to the receiving unit 130 via signal lines 121 and 122 in the transmission path 120. Either a differential signal or a non-differential signal is supplied under the control of the logic circuit 230. Furthermore, the amplitude of the differential signal from the driver circuit 300 is assumed to be smaller than that of the non-differential signal.

[Configuration example of drive circuit]
3 is a circuit diagram showing an example of a configuration of a drive circuit 300 according to the first embodiment of the present technology. The drive circuit 300 includes a drive unit 305 and a transformer 360.

Driver 305 supplies either a non-differential signal (in-phase signal or single-phase signal) with a larger amplitude than the differential signal or a differential signal to transformer 360 in accordance with control signals DIF and SC. Driver 305 includes non-differential drivers 310 and 320 and differential driver 330. Differential driver 330 includes drivers 331 and 332.

Transformer 360 is also provided with magnetically coupled coils 361 and 362. The inductances of coils 361 and 362 are approximately the same.

Here, let's assume that coil 361 is the primary side. When a primary voltage is applied across it, a secondary voltage of opposite polarity to the primary voltage is generated across coil 362. However, in transformer 360, coils 361 and 362 are not used as the primary and secondary sides. One end of coil 361 is connected to the output terminal of driver 331, and the other end is connected to output signal line 121. One end of coil 362 is connected to the output terminal of driver 332, and the other end is connected to output signal line 122. Driver 305 supplies a differential signal to one end of coil 361 and one end of coil 362. When an in-phase current is applied to the end of coil 361 connected to driver 305 and the end of coil 362 connected to driver 305, the magnetic fluxes created by each coil weaken each other. Furthermore, when a differential current is applied to one end of the coil 361 connected to the drive unit 305 and one end of the coil 362 connected to the drive unit 305, the magnetic fluxes created by the coils reinforce each other.

Note that coil 361 is an example of the first coil described in the claims, and coil 362 is an example of the second coil described in the claims.

Referring to Figure 4, the winding directions of coils 361 and 362 will be described in detail. Coils 361 and 362 share a predetermined winding axis W, and each wire is wound around that axis. One end of wire 361-1 constituting coil 361 is designated 361-2, and the other end is designated 361-3. One end of wire 362-1 constituting coil 362 is designated 362-2, and the other end is designated 362-3. One end 361-2 and 362-2 are connected to the driving unit 305. The other ends 361-3 and 362-3 are connected to the receiving unit 130. The figure is a plan view of coils 361 and 362 as viewed from the direction of winding axis W. The arrows indicate the direction of current flow when in-phase currents flow from 361-2 and 362-2. The winding direction of the wire 361-1 of the coil 361 around the winding axis W is opposite to the winding direction of the wire 362-1 of the coil 362 around the winding axis W. For example, as illustrated in the figure, the wire 361-1 is wound clockwise, while the wire 362-1 is wound counterclockwise.

Returning to FIG. 3, the non-differential driver 310 adjusts the amplitude of the non-differential signal from the serializer 240 and supplies it to one end of the coil 361. This non-differential driver 310 includes, for example, an inverter 311, switches 312 to 315, a p-channel Metal Oxide Semiconductor (pMOS) transistor 316, and an n-channel MOS (nMOS) transistor 317. The inverter 311 inverts the signal input to the non-differential driver 310. The switch 312 opens and closes the path between the output terminal of the inverter 311 and the gate of the pMOS transistor 316 in accordance with a control signal SC. The switch 313 opens and closes the path between the output terminal of the inverter 311 and the gate of the nMOS transistor 317 in accordance with a control signal SC. The switch 314 opens and closes the path between the power supply terminal and the gate of the pMOS transistor 316 in accordance with a control signal SC. The switch 315 opens and closes the path between the ground terminal and the gate of the nMOS transistor 317 in accordance with a control signal SC. The pMOS transistor 316 and the nMOS transistor 317 are connected in series between a power supply terminal and a ground terminal, and the voltage at their connection node is output as the output signal of the non-differential driver 310. When the switches 312 and 313 are closed, the switches 314 and 315 are open, and the non-differential driver 310 is in a driven state. When the switches 312 and 313 are open, the switches 314 and 315 are closed, and the non-differential driver 310 is in a stopped state. The circuit configurations of the non-differential driver 320, the driver 331, and the driver 332 are the same as that of the non-differential driver 310. A non-differential signal is input to the non-differential drivers 310 and 320 via signal lines 241 and 244. A differential signal is input to the drivers 331 and 332 via signal lines 242 and 243.

When transmitting in a differential signal output state, the logic circuit 230 drives drivers 331 and 332 with the control signal DIF and stops non-differential drivers 310 and 320 with the control signal SC.

In addition, when transmitting in a non-differential signal output state, the logic circuit 230 drives the non-differential drivers 310 and 320 with the control signal SC and stops the drivers 331 and 332 with the control signal DIF.

In the non-differential signal output state, non-differential drivers 310 and 320 supply a non-differential signal Dsc consisting of Dsc1 and Dsc2.

Driver 331 adjusts the amplitude of the positive phase signal Dp of the differential signals and supplies it to one end of coil 361. Driver 332 adjusts the amplitude of the negative phase signal Dn of the differential signals and supplies it to one end of coil 362.

In addition, the DC (Direct Current) output voltage of non-differential drivers 310 and 320 is higher than that of drivers 331 and 332 in differential driver 330. This makes the amplitude of the low-speed non-differential signal larger than the amplitude of the high-speed differential signal.

With the circuit configuration illustrated in the figure, in the differential signal output state, the differential driver 330 is driven to supply a high-speed, small-amplitude differential signal to the receiving unit 130 via the transformer 360. In the non-differential signal output state, the non-differential drivers 310 and 320 are driven to supply a low-speed, large-amplitude common-mode signal or single-phase signal to the receiving unit 130 via the transformer 360.

In addition, by inserting coils 361 and 362, the rise time and fall time of the differential signal can be shortened in the differential signal output state. This peaking allows the transmission speed of the differential signal to be improved compared to when coils 361 and 362 are not inserted. Furthermore, even in the non-differential signal output state, although the rise time and fall time are shortened by inserting coils 361 and 362, the inductance of these coils is smaller than when these coils are not magnetically coupled. Therefore, the decrease in rise time and fall time is smaller than when they are not magnetically coupled, and EMI noise can be sufficiently suppressed. The reason why the inductance is relatively small in the non-differential signal output state will be discussed later.

Here, as a comparative example, consider a drive circuit in which a pair of non-magnetically coupled coils are inserted instead of the magnetically coupled coils 361 and 362.

Figure 5 is a circuit diagram showing an example configuration of a drive circuit in a comparative example. As illustrated in the figure, in the comparative example, a pair of coils that are not magnetically coupled are inserted between the output terminals of drivers 331 and 332 and signal lines 121 and 122.

6 is a diagram for comparing the inductance between the first embodiment of the present technology and a comparative example. In the first embodiment, the inductance of the transformer 360 with respect to the differential signal corresponds to the combined inductance of the coils 361 and 362. When the inductance of each of the coils 361 and 362 is L, the inductance L _diff of the transformer 360 with respect to the differential signal is expressed by the following equation:
L _diff =2L+2M...Formula 1
In the above equation, M is the mutual inductance, which is expressed by the following equation:
M=kL...Formula 2
In the above equation, k is a coupling coefficient, and is, for example, a positive real number less than 1. Substituting equation 2 into equation 1, the following equation is obtained.
L _diff =2(1+k)L...Formula 3

On the other hand, in the comparative example, the total inductance of the pair of coils for the differential signal is 2L.

Next, in the first embodiment, the combined inductance of the transformer 360 for an in-phase signal is expressed by the following equation because the polarity of the mutual inductance is opposite.
(1-k)L/2...Formula 4

On the other hand, in the comparative example, the inductance of a pair of coils for an in-phase signal is L/2.

To compare the inductance with respect to a common-mode signal, the inductance of the first embodiment in differential mode is matched to that of the comparative example. For example, the inductance of the coils 361 and 362 of the first embodiment is adjusted to L' expressed by the following equation:
L'=L/(1+k)...Formula 5

From Equation 5, the inductance L _com of the first embodiment after adjustment is expressed by the following equation.
L _com = {(1-k)/(1+k)}L/2...Formula 6

From Equation 6, in the first embodiment using magnetically coupled coils 361 and 362, the inductance for in-phase signals is smaller than L/2 in the comparative example. This increases the rise time and fall time compared to the comparative example, enabling EMI noise to be suppressed. Since the inductance for single-phase signals is L/(1+k), EMI noise can be similarly suppressed in single-phase mode.

On the other hand, after adjustment, the inductance of the first embodiment for the differential signal is the same as that of the comparative example, so as with the comparative example, the transmission speed can be improved by inserting a coil.

As described above, by using magnetically coupled coils 361 and 362, it is possible to achieve both noise suppression and improved transmission speed.

[Driver circuit operation example]
7A and 7B are timing charts showing an example of operation of the drive circuit according to the first embodiment of the present technology and a comparative example. A portion of the timing chart in Fig. 7A shows an example of operation of the drive circuit 300 according to the first embodiment. A portion of the timing chart in Fig. 7B shows an example of operation of the comparative example.

The differential signal output state is set up until timing T1, and the non-differential signal output state is set after timing T1. As illustrated in FIG. 1A, in the differential signal output state, differential signals consisting of a positive-phase signal Dp and a negative-phase signal Dn, which have smaller amplitudes and higher speeds than the in-phase signal and single-phase signal, are transmitted. In the non-differential signal output state, a non-differential signal Dsc, which has larger amplitudes and lower speeds than the differential signal, is transmitted. In FIG. 1A, an in-phase signal is transmitted as the non-differential signal.

As illustrated in Fig. 1B, the rise time and fall time of the differential signal in the comparative example are the same as those in the first embodiment, but the rise time _dT1 of the common-mode signal is shorter than the rise time _dT0 in the first embodiment.

As shown in the figure, differential transitions are prohibited for low-speed, large-amplitude signals, and they are transmitted using single-phase or common-phase transitions. Furthermore, as mentioned above, transformer 360 acts as an inductor only for differential waveforms, reducing the contribution of output capacitance. This makes it possible to steepen the rise of high-speed, small-amplitude differential signals while suppressing peaking of low-speed, large-amplitude single-phase and common-phase signals, enabling both high-speed operation and EMI suppression.

As described above, according to the first embodiment of the present technology, by providing magnetically coupled coils 361 and 362, it is possible to reduce the inductance for in-phase signals and the inductance for single-phase signals compared to when non-magnetically coupled coils are used. This suppresses peaking of in-phase transitions and single-phase transitions, thereby achieving both improved transmission speed and noise suppression.

2. Second embodiment
In the first embodiment described above, the output terminals of the non-differential drivers 310 and 320 are connected to one end of the coils 361 and 362. However, this configuration may not be able to sufficiently reduce the influence of the output capacitance of the non-differential drivers 310 and 320 on the waveform. The drive circuit 300 of this second embodiment differs from the first embodiment in that the destinations to which the output terminals of the non-differential drivers 310 and 320 are connected are changed.

As described above, according to the second embodiment of the present technology, the output terminals of the non-differential drivers 321 and the like are connected to a node (such as a center tap) between both ends of the coil, so that the influence of the output capacitance of the non-differential drivers 310 and 320 can be sufficiently reduced.

When the output terminals of the non-differential drivers 310 and 320 are connected to the center taps 365 and 366, the inductance L _com for the common-mode signal is expressed by the following equation.
L _com = (1-k) {L/4} ...Formula 7

Note that the output terminals of non-differential drivers 310 and 320 are connected to center taps 365 and 366, but the connection destination is not limited to the center tap as long as it is a node between both ends of coils 361 and 362.

As such, according to the second embodiment of the present technology, the output terminals of the non-differential driver 310, etc. are connected to a node (such as a center tap) between both ends of the coil, thereby sufficiently reducing the influence of the output capacitance of the non-differential drivers 310 and 320.

3. Third embodiment
In the first embodiment described above, the inductance in the non-differential signal output state is reduced by using magnetically coupled coils 361 and 362. However, this configuration may not be able to sufficiently reduce the effect of the driver's output capacitance on the waveform. The drive circuit 300 of this third embodiment differs from the first embodiment in that ESD (Electro-Static Discharge) protection diodes are connected to the coils 361 and 362.

Figure 9 is a circuit diagram showing an example configuration of a drive circuit 300 in a third embodiment of the present technology. The drive circuit 300 of this third embodiment differs from the first embodiment in that it further includes ESD protection diodes 371 to 374.

ESD protection diodes 371 and 372 are connected in series between the power supply terminal and the ground terminal. The connection node of these ESD protection diodes 371 and 372 is connected to the center tap 365 of the coil 361.

ESD protection diodes 373 and 374 are connected in series between the power supply terminal and the ground terminal. The connection node of these ESD protection diodes 373 and 374 is connected to the center tap 366 of the coil 362.

Note that ESD protection diodes 371 and 372 are examples of the first ESD protection diodes described in the claims. ESD protection diodes 373 and 374 are examples of the second ESD protection diodes described in the claims.

By connecting ESD protection diodes 371 to 374, the impact of the driver's output capacitance on the waveform is sufficiently reduced, improving the waveform as in the second embodiment.

Note that although the ESD protection diodes 371 to 374 are connected to the center tap, they can be connected to any node between both ends of the coils 361 and 362, and are not limited to the center tap.

As such, according to the third embodiment of the present technology, by connecting ESD protection diodes 371 to 374 to coils 361 and 362, the impact of the driver's output capacitance on the waveform can be sufficiently reduced.

4. Fourth embodiment
In the first embodiment described above, different drivers are used for the differential signal output state and the non-differential signal output state, but a common driver can also be used for both states. The drive circuit 300 of this fourth embodiment differs from the first embodiment in that a common driver is used for each operating state.

Figure 10 is a circuit diagram showing an example configuration of a drive circuit 300 in a fourth embodiment of the present technology. The drive circuit 300 of this fourth embodiment differs from the first embodiment in that an output voltage control unit 341, switches 353 to 356, and shared drivers 351 and 352 are arranged within the drive unit 305.

The output voltage control unit 341 controls the DC output voltage of the shared drivers 351 and 352 according to the control signal DIF. This output voltage control unit 341 reduces the output voltage in the differential signal output state to a level lower than that in the non-differential signal output state.

The shared driver 351 supplies a differential signal (such as a positive-phase signal) or a non-differential signal from the serializer 240 to one end of the coil 361. The shared driver 352 supplies a differential signal (such as a negative-phase signal) or a non-differential signal from the serializer 240 to one end of the coil 362.

Switch 353 opens and closes the path between input signal line 241 and the input terminal of shared driver 351 in accordance with the control signal SC. Switch 352 opens and closes the path between input signal line 242 and the input terminal of shared driver 351 in accordance with the control signal DIF. Switch 353 opens and closes the path between input signal line 243 and the input terminal of shared driver 352 in accordance with the control signal DIF. Switch 354 opens and closes the path between input signal line 244 and the input terminal of shared driver 352 in accordance with the control signal SC.

When transmitting in a non-differential signal output state, logic circuit 230 closes switches 353 and 356 using control signal SC and opens switches 354 and 355 using control signal DIF. When transmitting in a differential signal output state, logic circuit 230 closes switches 354 and 355 using control signal DIF and opens switches 353 and 356 using control signal SC.

By using shared drivers 351 and 352 in common for each operating state, the number of drivers can be reduced compared to the first embodiment.

As such, according to the fourth embodiment of the present technology, shared drivers 351 and 352 are commonly used in each operating state, thereby reducing the number of drivers compared to when different drivers are used in each operating state.

5. Fifth embodiment
In the first embodiment described above, the driving unit 305 and the transformer 360 are arranged on the circuit chip 202, but this configuration makes it difficult to further reduce the circuit scale of the circuit chip 202. The driving circuit 300 of this fifth embodiment differs from the first embodiment in that the transformer 360 is arranged outside the circuit chip 202.

Figure 11 is a circuit diagram showing an example configuration of a drive circuit 300 in a fifth embodiment of the present technology. The drive circuit 300 of this fifth embodiment differs from the first embodiment in that the transformer 360 is arranged in the transmission path 120 outside the circuit chip 202. The squares in the figure represent pads. By arranging the transformer 360 outside the circuit chip 202, the circuit scale of the circuit chip 202 can be reduced. Note that the circuit chip 202 is an example of a semiconductor chip as defined in the claims.

As such, according to the fifth embodiment of the present technology, the transformer 360 is arranged outside the circuit chip 202, thereby reducing the circuit scale of the circuit chip 202.

6. Sixth embodiment
In the second embodiment described above, the inductance in the non-differential signal output state is reduced by using magnetically coupled coils 361 and 362. However, this configuration may not be able to sufficiently reduce the influence of the driver's output capacitance on the waveform. The drive circuit 300 of this sixth embodiment differs from the second embodiment in that the third embodiment is applied to the second embodiment.

Figure 12 is a circuit diagram showing an example configuration of a drive circuit 300 in a sixth embodiment of the present technology. The drive circuit 300 of this sixth embodiment differs from the second embodiment in that it further includes the ESD protection diodes 371 to 374 of the third embodiment.

By connecting ESD protection diodes 371 to 374, the impact of the driver's output capacitance on the waveform can be significantly reduced.

Note that while the output terminals of non-differential drivers 310 and 320 are connected to the center tap, they can be connected to any node between both ends of coils 361 and 362, and are not limited to the center tap. The same applies to ESD protection diodes 371 to 374.

As such, according to the sixth embodiment of the present technology, by connecting ESD protection diodes 371 to 374 to coils 361 and 362, the impact of the driver's output capacitance on the waveform can be sufficiently reduced.

7. Seventh embodiment
In the third embodiment described above, different drivers are used for the differential signal output state and the non-differential signal output state, but a common driver can also be used for both operating states. The drive circuit 300 of this seventh embodiment differs from the third embodiment in that the fourth embodiment is applied to the third embodiment.

Figure 13 is a circuit diagram showing an example configuration of a drive circuit 300 according to a seventh embodiment of the present technology. The drive circuit 300 of this seventh embodiment differs from the third embodiment in that the output voltage control unit 341, switches 353 to 356, and shared drivers 351 and 352 of the fourth embodiment are arranged within the drive unit 305.

By using shared drivers 351 and 352 in common for each operating state, the number of drivers can be reduced compared to the third embodiment.

As such, according to the seventh embodiment of the present technology, the shared drivers 351 and 352 are commonly used in each operating state, thereby reducing the number of drivers compared to when different drivers are used in each operating state.

8. Eighth embodiment
In the above-described fourth embodiment, the driving unit 305 and the transformer 360 are arranged on the circuit chip 202, but this configuration makes it difficult to further reduce the circuit scale of the circuit chip 202. The driving circuit 300 of this eighth embodiment differs from the fourth embodiment in that the fifth embodiment is applied to the fourth embodiment.

Figure 14 is a circuit diagram showing an example configuration of a drive circuit 300 in an eighth embodiment of the present technology. The drive circuit 300 of this eighth embodiment differs from the fourth embodiment in that the transformer 360 is arranged in the transmission path 120 outside the circuit chip 202. This allows the circuit scale of the circuit chip 202 to be reduced.

As such, according to the eighth embodiment of the present technology, the transformer 360 is arranged outside the circuit chip 202, thereby reducing the circuit scale of the circuit chip 202.

9. Ninth embodiment
In the first embodiment described above, the driving circuit 300 outputs signals to two lines, the signal lines 121 and 122, but it is also possible to output signals to three lines. The driving circuit 300 of this ninth embodiment differs from the first embodiment in that it outputs signals to three lines.

Figure 15 is a circuit diagram showing an example configuration of a drive circuit 300 in a ninth embodiment of the present technology. The drive circuit 300 of this ninth embodiment differs from the first embodiment in that it further includes a non-differential driver 321, a driver 333, and a coil 363.

Driver 333, together with drivers 331 and 332, forms a differential driver. The output voltage of non-differential driver 321 is higher than that of the differential driver. Driver 333 and non-differential driver 321 supply Dq, which constitutes a differential signal, or Dsc3, which constitutes a non-differential signal, to one end of coil 363.

Coil 363 is magnetically coupled to coil 362, and the other end is connected to the receiving unit 130 via signal line 123. Furthermore, the inductance of coil 363 is approximately the same as that of coil 362, and the winding direction of coil 363 from driver 333 to signal line 123 is different from the winding direction of coil 362 from driver 332 to signal line 122.

When transmitting in a differential signal output state, the logic circuit 230 drives drivers 331 to 333 using the control signal DIF and stops non-differential drivers 310, 320, and 321 using the control signal SC.

In addition, when transmitting in a non-differential signal output state, the logic circuit 230 stops drivers 331 to 333 using the control signal DIF and drives non-differential drivers 310, 320, and 321 using the control signal SC.

Note that while the drive circuit 300 transmits signals via three wires, it is also possible to transmit signals via four or more wires. Furthermore, each of the second to eighth embodiments can be applied to the ninth embodiment.

As such, according to the ninth embodiment of the present technology, a non-differential driver 321, a driver 333, and a coil 363 are further provided, thereby enabling signals to be transmitted via three wires.

<10. Application examples for mobile devices>
The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

Figure 16 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology disclosed herein can be applied.

The vehicle control system 12000 includes multiple electronic control units connected via a communication network 12001. In the example shown in Figure 16, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside vehicle information detection unit 12030, an inside vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio/video output unit 12052, and an in-vehicle network I/F (interface) 12053.

The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a driveforce generating device for generating vehicle driveforce, such as an internal combustion engine or drive motor, a driveforce transmission mechanism for transmitting driveforce to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating braking force for the vehicle.

The body system control unit 12020 controls the operation of various devices installed in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves or signals from various switches transmitted from a portable device that serves as a key can be input to the body system control unit 12020. The body system control unit 12020 accepts these radio waves or signal inputs and controls the vehicle's door lock device, power window device, lamps, etc.

The outside vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, the outside vehicle information detection unit 12030 is connected to the imaging unit 12031. The outside vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image, or as distance measurement information. Furthermore, the light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

The in-vehicle information detection unit 12040 detects information inside the vehicle. Connected to the in-vehicle information detection unit 12040 is, for example, a driver state detection unit 12041 that detects the state of the driver. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver. The in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

The microcomputer 12051 can calculate control target values for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the vehicle's surroundings obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

In addition, the microcomputer 12051 can output control commands to the body system control unit 12020 based on information outside the vehicle acquired by the outside vehicle information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside vehicle information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

The audio/video output unit 12052 transmits at least one audio and/or video output signal to an output device capable of visually or audibly notifying vehicle occupants or the outside of the vehicle of information. In the example of Figure 16, the output devices are exemplified by an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

Figure 17 is a diagram showing an example of the installation location of the imaging unit 12031.

In Figure 17, the imaging unit 12031 has imaging units 12101, 12102, 12103, 12104, and 12105.

The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided on the top of the windshield inside the vehicle cabin is mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

Note that Figure 17 shows an example of the imaging ranges of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 provided on the rear bumper or tailgate. For example, by overlaying the image data captured by imaging units 12101 to 12104, an overhead image of vehicle 12100 viewed from above is obtained.

At least one of the imaging units 12101 to 12104 may have a function to acquire distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple imaging elements, or an imaging element having pixels for phase difference detection.

For example, based on distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed relative to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the closest three-dimensional object on the path of the vehicle 12100 that is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km/h or higher). Furthermore, the microcomputer 12051 can set the inter-vehicle distance that should be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control) and automatic acceleration control (including follow-up start control). In this way, cooperative control can be performed for the purpose of autonomous driving, which travels autonomously without relying on driver operation.

For example, based on distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can classify and extract three-dimensional object data regarding three-dimensional objects into categories such as motorcycles, standard vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects, and use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into those that are visible to the driver of the vehicle 12100 and those that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the risk of collision with each obstacle. When the collision risk is equal to or exceeds a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alert to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or evasive steering via the drivetrain control unit 12010.

At least one of the image capture units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize pedestrians by determining whether a pedestrian is present in the images captured by the image capture units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capture units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether or not the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capture units 12101 to 12104 and recognizes the pedestrian, the audio/image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio/image output unit 12052 may also control the display unit 12062 to display an icon or the like representing the pedestrian in a desired position.

The above describes an example of a vehicle control system to which the technology disclosed herein can be applied. The technology disclosed herein can be applied to, for example, the imaging unit 12031 of the above-described configuration. Specifically, the imaging device 100 of FIG. 1 can be applied to the imaging unit 12031. By applying the technology disclosed herein to the imaging unit 12031, it is possible to improve transmission speed while reducing noise and obtain easier-to-view captured images, thereby reducing driver fatigue.

Note that the above-described embodiment shows an example of how the present technology can be realized, and there is a corresponding relationship between the matters in the embodiment and the matters specifying the invention in the claims. Similarly, there is a corresponding relationship between the matters specifying the invention in the claims and the matters in the embodiment of the present technology that have the same title. However, the present technology is not limited to the embodiment, and can be realized by making various modifications to the embodiment within the scope of its gist.

Please note that the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

The present technology can also be configured as follows.
(1) a transformer having a plurality of magnetically coupled coils;
a driver that supplies either a non-differential signal or a differential signal to the transformer;
the plurality of coils includes first and second coils that are magnetically coupled;
the driving unit is connected to one end of the first coil and one end of the second coil,
A drive circuit in which, when a current of the same phase is applied to the one end of each of the first and second coils, the magnetic fluxes generated by the first and second coils weaken each other.
(2) The drive circuit described in (1) above, wherein the drive unit supplies the differential signal to one end of the first coil and one end of the second coil, and the drive unit supplies the differential signal to one end of the first coil and one end of the second coil.
(3) a first ESD protection diode connected to a node between both ends of the first coil;
The drive circuit according to (2), further comprising a second ESD protection diode connected to a node between both ends of the second coil.
(4) The drive unit is
a shared driver that supplies either the differential signal or the non-differential signal;
The drive circuit according to (2) or (3), further comprising an output voltage control unit that controls an output voltage of the shared driver.
(5) the driving unit is disposed on a predetermined semiconductor chip;
The drive circuit according to (4), wherein the transformer is disposed outside the semiconductor chip.
(6) The drive unit is
a differential driver for providing the differential signals;
The drive circuit according to (2), further comprising: a non-differential driver that supplies the non-differential signal.
(7) The drive circuit according to (6), wherein the output terminal of the non-differential driver is connected to a node between both ends of either the first or second coil.
(8) The drive circuit according to (7), wherein the output terminal of the non-differential driver is connected to the one end of either the first or second coil.
(9) The driving unit is disposed on a predetermined semiconductor chip,
The drive circuit according to (8), wherein the transformer is disposed outside the semiconductor chip.
(10) The plurality of coils includes first, second, and third coils that are magnetically coupled together;
the driving unit supplies the differential signal to one end of the first coil, one end of the second coil, and one end of the third coil;
The drive circuit according to (1), wherein when a common-mode current is applied to the one end of each of the second and third coils, the magnetic fluxes generated by the second and third coils weaken each other.
(11) Further comprising a receiver that receives a differential signal via the first and second signal lines;
the driver includes first and second output terminals;
the first coil has one end connected to the first output terminal and the other end connected to the first signal line;
The drive circuit according to (1), wherein the one end of the second coil is connected to the second output terminal and the other end is connected to the second signal line.
(12) The first and second coils share a predetermined winding axis;
When viewed from the direction of the winding axis, the winding direction of the first coil around the winding axis from one end connected to the output terminal of the wiring to the other end connected to the signal line is opposite to the winding direction of the second coil around the winding axis from one end connected to the output terminal of the wiring to the other end connected to the signal line.
The drive circuit according to (1) above.
(13) A transformer having a plurality of magnetically coupled coils;
a driver that supplies either a non-differential signal or a differential signal to the transformer in accordance with a predetermined control signal;
a logic circuit that specifies either the non-differential signal or the differential signal by the control signal and supplies the signal to the driver;
the plurality of coils includes first and second coils that are magnetically coupled;
the driving unit is connected to one end of the first coil and one end of the second coil,
When a current of the same phase is applied to the one end of each of the first and second coils, the magnetic fluxes generated by the first and second coils weaken each other.

100 Imaging device 110 Mounting board 120 Transmission path 130 Receiving unit 200 Solid-state imaging element 201 Pixel chip 202 Circuit chip 210 Pixel 220 Analog-to-digital conversion unit 230 Logic circuit 240 Serializer 300 Drive circuit 305 Drive unit 310, 320, 321 Non-differential driver 311 Inverter 312 to 315, 353 to 356 Switch 316 pMOS transistor 317 nMOS transistor 330 Differential driver 331 to 333 Driver 341 Output voltage control unit 351, 352 Shared driver 360 Transformer 361 to 363 Coil 371 to 374 ESD protection diode 12031 Imaging unit

Claims (7)

a transformer having a plurality of magnetically coupled coils;
a driver that supplies either a non-differential signal or a differential signal to the transformer ;
a first ESD protection diode connected to a first node between both ends of the first coil;
a second ESD protection diode connected to a second node between both ends of the second coil;
Equipped with
the plurality of coils includes the first and second coils that are magnetically coupled;
the driving unit is connected to one end of the first coil and one end of the second coil,
When a current of the same phase is applied to the one end of each of the first and second coils, the magnetic fluxes generated by the first and second coils weaken each other ,
The drive unit is
a differential driver for providing the differential signals;
a non-differential driver for providing said non-differential signal;
Equipped with
the non-differential driver includes a first non-differential driver and a second non-differential driver;
an output terminal of the first non-differential driver connected to the first node;
The output terminal of the second non-differential driver is connected to the second node.
Drive circuit. The drive circuit of claim 1, wherein the drive unit supplies the differential signal to one end of the first coil and one end of the second coil, and the differential signal is output from the other end of each of the first and second coils. the driving unit is disposed on a predetermined semiconductor chip,
2. The drive circuit according to claim 1 , wherein the transformer is disposed outside the semiconductor chip. a receiver that receives a differential signal via the first and second signal lines;
the driver includes first and second output terminals;
the first coil has one end connected to the first output terminal and the other end connected to the first signal line;
2. The drive circuit according to claim 1, wherein the one end of the second coil is connected to the second output terminal, and the other end is connected to the second signal line. the first and second coils share a predetermined winding axis;
2. The drive circuit according to claim 1, wherein, when viewed from the direction of the winding axis, the winding direction of the first coil around the winding axis from one end connected to the output terminal of the wiring of the first coil to the other end connected to the signal line is opposite to the winding direction of the second coil around the winding axis from one end connected to the output terminal of the wiring of the second coil to the other end connected to the signal line. a transformer having a plurality of magnetically coupled coils;
a driver that supplies either a non-differential signal or a differential signal to the transformer;
Equipped with
the plurality of coils includes first, second, and third coils that are magnetically coupled;
the driving unit supplies the differential signal to one end of the first coil, one end of the second coil, and one end of the third coil;
When a current of the same phase is applied to the one end of each of the first and second coils, the magnetic fluxes generated by the first and second coils weaken each other,
When a common-mode current is applied to the one end of each of the second and third coils, the magnetic fluxes generated by the second and third coils weaken each other.
Drive circuit. a transformer having a plurality of magnetically coupled coils;
a driver that supplies either a non-differential signal or a differential signal to the transformer in accordance with a predetermined control signal ;
a first ESD protection diode connected to a first node between both ends of the first coil;
a second ESD protection diode connected to a second node between both ends of the second coil;
a logic circuit that specifies either the non-differential signal or the differential signal by the control signal and supplies the signal to the driver;
the plurality of coils includes the first and second coils that are magnetically coupled;
the driving unit is connected to one end of the first coil and one end of the second coil,
When a current of the same phase is applied to the one end of each of the first and second coils, the magnetic fluxes generated by the first and second coils weaken each other,
The drive unit is
a differential driver for providing the differential signals;
a non-differential driver for providing said non-differential signal;
Equipped with
the non-differential driver includes a first non-differential driver and a second non-differential driver;
an output terminal of the first non-differential driver connected to the first node;
The output terminal of the second non-differential driver is connected to the second node.
Solid-state imaging element.