A driving circuit and driving method

Abstract

This invention provides a driving circuit, characterized by comprising: a target waveform conversion unit for converting target waveform information into a current or voltage signal; the converted current or voltage signal being output to a first sampling circuit and a second sampling circuit; a calculation module for outputting an action command based on the output results of the first and second sampling circuits; and a TDC module for outputting time parameters of a counting interval based on the action command output by the calculation module. This circuit can automatically acquire time information of a predetermined interval, such as the rising or falling edge time information, which can be used to calibrate transmission or, in time-of-flight ranging schemes, calibrate the final ranging result, making the emitted light waveform of the transmitter or the ranging result more accurate.

Description

Technical Field

[0001] This invention relates to the field of drive circuits, and more specifically, to a drive circuit and a drive method. Background Technology

[0002] The rise / fall times of signals propagating between the CPU and chipset typically vary due to one or more external influences. These influences include variations in silicon strength caused by process, voltage, and / or temperature conditions present on numerous dies. Uncompensated power supply voltage variations can also lead to rise / fall time variations. If left unaddressed, these variations will adversely affect system performance. For example, if the rise / fall time is too slow, timing failures may occur. Conversely, if the rise / fall time is too fast, signal integrity and reliability issues may arise due to large reflections and overshoot / undershoot effects. For active light source detection systems, such as laser-based ranging systems, driving the laser source to emit a specific waveform is crucial for detection; however, the accuracy of the waveform largely depends on the precise control of the rise and fall times.

[0003] Rise time refers to the time it takes for a digital logic circuit to transition from a low logic level to a high logic level (e.g., from "0" to "1"), while fall time is the time required for a high logic level to transition to a low logic level (e.g., from "1" to "0"). Knowing that pulse rise and fall times (rising edge and falling edge) are within specified ranges is fundamental to pulse usage in measurement and test applications. The extent to which pulse rise and / or fall times affect the required device performance depends on the nature of the device and the type of test to be performed.

[0004] Most pulse generators do not offer separate self-contained verification of rise and fall times, nor do they offer independent automatic self-contained adjustment of rise and fall times. Such devices typically require the use of an external oscilloscope and automated test equipment controller or a trained operator to perform pulse rise and fall time verification.

[0005] One drawback of this solution is the need for an oscilloscope (at an additional cost) and an automated test controller (dedicated computer and software) or a trained operator. A second drawback is that the operation of the rise and fall time circuits can be affected by operating temperature or component aging, and may require continuous or frequent calibration. If relatively complex measurements or procedures are needed to adjust for these effects, users may find adjustments inconvenient and operate the instrument under less than ideal conditions.

[0006] In addition, due to the rise and fall times in the TOF ranging process, the distance to the detected object confirmed by the time of flight will have a certain deviation. In order to obtain more accurate detection results, a method that can obtain the rise and fall times is needed.

[0007] To solve the above problems, there is an urgent need for a method that can quickly and accurately determine the waveform of the driven light source to achieve precise detection circuitry and methods, and can be integrated with the transmitter driver to realize a laser transmitter with self-detection and calibration correction. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of the prior art by providing a driving circuit and driving method to solve the problems in the related art, such as the inability to accurately control the waveform at the transmitting end or the inability to achieve more accurate output of ranging results.

[0009] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0010] In a first aspect, embodiments of the present invention provide a driving circuit, characterized in that it includes:

[0011] The target waveform conversion unit is used to convert target waveform information into current or voltage signals.

[0012] The converted current or voltage signal is output to the first sampling circuit and the second sampling circuit;

[0013] The arithmetic module outputs action commands based on the output results of the first sampling circuit and the second sampling circuit;

[0014] The TDC module outputs the time parameters of the counting interval according to the action instructions output by the arithmetic module.

[0015] Optionally, the current or voltage signal after the target waveform is converted includes a rising edge and a falling edge, and the time parameter of the counting interval output by the TDC module is at least a portion of the total time of the rising edge and / or the falling edge.

[0016] Optionally, the first sampling circuit has a first output threshold, the second sampling circuit has a second output threshold, and the first output threshold is less than the second output threshold.

[0017] Optionally, the arithmetic module includes a first switching module and a second switching module. When the first sampling circuit reaches a first output threshold, the level of the first switching module switches; when the second sampling circuit reaches a second output threshold, the level of the second switching module switches.

[0018] Optionally, the arithmetic module includes an OR operation unit, which outputs an action command based on the output results of the first sampling circuit and the second sampling circuit.

[0019] Optionally, the TDC module has picosecond-level accuracy.

[0020] Optionally, it may also include a first output threshold and a second output threshold adjustment module, wherein the first output threshold and the second output threshold adjustment module include an adjustable resistor, the value of which determines the first output threshold and the second output threshold.

[0021] Optionally, the adjustable resistance value of the threshold adjustment module is adjusted in at least one of the following ways:

[0022] Power-on calibration, preset time period adjustment, adaptive adjustment, etc.

[0023] Optionally, it also includes a latching module, which latches the time parameters of the counting interval output by the TDC module according to the action instructions output by the arithmetic module.

[0024] Secondly, the present invention also provides a driving method implemented using the driving circuit of the first aspect, comprising:

[0025] The target waveform conversion unit is used to convert target waveform information into current or voltage signals.

[0026] The converted current or voltage signal is output to the first sampling circuit and the second sampling circuit;

[0027] The arithmetic module outputs action commands based on the output results of the first sampling circuit and the second sampling circuit;

[0028] The TDC module outputs the time parameters of the counting interval according to the action instructions output by the arithmetic module.

[0029] Optionally, the current or voltage signal after the target waveform is converted includes a rising edge and a falling edge, and the time parameter of the counting interval output by the TDC module is at least a portion of the total time of the rising edge and / or the falling edge.

[0030] Optionally, the first sampling circuit has a first output threshold, the second sampling circuit has a second output threshold, and the first output threshold is less than the second output threshold.

[0031] Optionally, the arithmetic module includes an OR operation unit, which outputs an action command based on the output results of the first sampling circuit and the second sampling circuit.

[0032] Optionally, it may also include a first output threshold and a second output threshold adjustment module, wherein the first output threshold and the second output threshold adjustment module include an adjustable resistor, the value of which determines the first output threshold and the second output threshold.

[0033] Optionally, it also includes a latching module, which latches the time parameters of the counting interval output by the TDC module according to the action instructions output by the arithmetic module.

[0034] The beneficial effects of this invention are as follows: This invention provides a driving circuit, characterized by comprising: a target waveform conversion unit for converting target waveform information into a current or voltage signal; the converted current or voltage signal is output to a first sampling circuit and a second sampling circuit; an arithmetic module that outputs an action command according to the output results of the first and second sampling circuits; and a TDC module that outputs a time parameter for the counting interval according to the action command output by the arithmetic module. This invention can convert a target waveform into a voltage or current signal, and process the converted voltage or current signal through two sampling circuits, obtaining the time value of the counting interval using the processing result. Compared with traditional circuits, it does not use a reference signal or a comparator design, ensuring greater simplicity, efficiency, and implementability of the circuit. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of a typical pulse waveform commonly used in the prior art;

[0037] Figure 2 A schematic diagram of a driving circuit provided in an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of another driving circuit provided in an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of another driving circuit provided in an embodiment of the present invention;

[0040] Figure 5 A schematic diagram of chip modularization provided for an embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram illustrating the storage of time information acquired by a TDC according to an embodiment of the present invention;

[0042] Figure 7 A schematic diagram of a circuit operation implementation provided in an embodiment of the present invention;

[0043] Figure 8 A schematic diagram illustrating a sine wave drive implemented using the present invention, provided as an embodiment of the present invention;

[0044] Figure 9 This is a schematic diagram illustrating how to accurately obtain the rise and fall times in TOF ranging to correct ranging accuracy, as provided in an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0046] Figure 1 This is a typical pulse waveform diagram commonly used in existing technologies. T represents the pulse in one period, Tr represents the rise time, Th represents the high hold time, TF represents the fall time, and Tl represents the low hold time. Therefore, one pulse period is T = Tr + Th + Tf + Tl. If the trigger level of the input pulse is used to measure different times of the input pulse, a typical time measurement system with low-cost testing equipment can detect whether the input pulse is rising or falling. For example, a measurement system with an input pulse of 0.1V at a trigger level of 1V (corresponding to a voltage level at 10% of 1V) and an amplitude of 0.9V (a voltage level corresponding to 90% of 1V) can measure the rise time (Tr) and fall time (Tf) of the input pulse. Of course, it is not limited to using these two thresholds; 15% and 85%, 20% and 80% can also be used. After final exploration, in order to ensure sufficient TDC running time to obtain higher accuracy, and on the other hand, to minimize TDC running time to ensure low power consumption of the circuit, etc., 20% and 80% are preferred as the set thresholds here. Of course, the results of the rising and falling edges of the current sampled data are similar to those of the voltage sampled data, and the specific implementation process is not limited here.

[0047] Figure 2This is a schematic diagram of a driving circuit provided in an embodiment of the present invention. In the implementation scheme provided by the present invention, a system driven by an active laser source detection is taken as an example. The waveform is a light wave, which can be obtained through a waveform conversion module, for example, the power requirement for driving the laser can be obtained from the waveform requirement, and then the power requirement can be converted into a current requirement. Here, the converted waveform, a micro-current waveform, is used as an example for illustration, but the actual implementation is not limited to current; voltage can also be used. Using current as an example here has the effect of easy implementation. For example, a current mirror can be used to divide the same current into several different paths, thus realizing the mirror replication of the current signal. Due to this characteristic, the mirrored current can be directly used without using an additional resistor to convert it into voltage, simplifying the circuit. In addition, the replicated multiple currents also provide a premise for setting different thresholds for the current of different circuits, which can save the complex implementation schemes of traditional ramp comparison signals or comparators. Figure 1 Here, the current is divided into two paths, with resistors R1 and R2 defining the threshold values ​​for each path. Taking 80% and 20% as examples, the resistor R1 in the first circuit is set so that the switching module switches at 20% of the highest current value. The switching module can consist of an even number of inverters. Similarly, the resistor R2 in the second circuit is set so that the switching module switches at 80% of the highest current value. Again, the switching module can consist of an even number of inverters. This is just one example and does not limit the specific implementation method. The two switching modules are... Figure 1 The results of the two jump modules, buffer1 and buffer2, are processed by the arithmetic unit. Figure 1 The XOR operation module in the circuit can output action commands for two circuits at different thresholds. The TDC can start or stop timing under the action command and latch the timing result. Furthermore, for traditional trapezoidal waves, the result of the TDC count can be used to obtain the rising edge and / or falling edge time. In order to ensure the accuracy of timing, the timing precision of the TDC needs to be guaranteed. For example, this invention can use a 50 picosecond level timer for timing operation. Of course, other similar picosecond level counters can also be used to ensure timing accuracy. It is not limited here. The action command of the operation module ensures the picosecond level precision of the TDC running time, thereby ensuring that the entire circuit design will not generate large power consumption due to the long working time of the high-precision TDC.

[0048] Figure 3 A schematic diagram of another driving circuit provided in this application, and Figure 2 The difference lies in the addition of an adaptive threshold setting scheme in this embodiment. By using a variable resistor, the threshold can be adjusted, allowing for different action commands to be obtained based on the adjusted threshold, and enabling adaptive adjustments to the scene. Figure 2 The waveform generation mechanism is similar. APC calibration can be used to obtain the current magnitude Itarget corresponding to the target optical power. Based on Itarget, 0.2Itarget and 0.8Itarget are calculated. First, the resistance value of the adjustable resistor is adjusted. Here, we take 80% and 20% as examples. S1 is closed, and IDAC is adjusted to 0.2Itarget / 1000 (the gain from Isense to Itarget in the circuit design is 1000). The resistance R1 is adjusted (from small to large). When the output of buffer1 changes from low to high, the adjustment of R1 is stopped through EN1, and the current output value of R1 is maintained. Similarly, S1 is opened, S2 is closed, IDAC is adjusted to 0.8Itarget / 1000, and the resistance R2 is adjusted (from small to large). When the output of buffer2 changes from low to high, the adjustment of R2 is stopped through EN2, and the current output value of R2 is maintained. Through this adjustment step, the resistance value of the adjustable resistor is confirmed under low current, ensuring low energy consumption throughout the adjustment process and rationalizing the power consumption of the entire drive module. When the resistance of the variable resistor is kept fixed, the circuit can operate as follows: S2 is opened, S0 is closed, and the sensor drives the laser through the LVDS driver chip. When the sampling current rises to 0.2Itarget / 1000, the output of buffer1 changes from low to high, and the XOR output goes high, starting TDC and beginning counting. This moment is recorded as t0. When the sampling current rises to 0.8Itarget / 1000, the output of buffer2 changes from low to high, and the XOR output goes low. This moment is recorded as t1. At this time, the counter data is latched into the register. Similarly, for the falling edge, when the current first drops to 0.8Itarget / 1000, the output of buffer2 goes low, and the XOR output goes high. This moment is recorded as t2. When the current drops to 0.2Itarget / 1000, the output of buffer1 goes low, and the XOR output goes low. This moment is recorded as t3. TDC stops, and the counting result is latched into the register. This operating process is similar to... Figure 2 The working process is similar. Here, we describe it from the perspective of the driving scheme within the driver chip. Of course, the above thresholds are not limited to 20% and 80%. The calibration of the thresholds can also be arranged in different time periods. For example, power-on calibration can be performed before power-on. During device operation, a fixed time or a random time period can be selected. Adaptive time period arrangements can also be made during use. For example, adaptive calibration can be arranged in the gaps between intervals in the use of the driver power supply. There are no restrictions here.

[0049] Figure 4 This is a schematic diagram of another driving circuit provided in an embodiment of the present invention, and... Figure 2 and Figure 3 The working principle is the same, so it will not be elaborated here. It should be noted that the current mirror here can divide the current into more than two paths. This can adapt to the transmission of special waveforms that are not traditional waveforms and the calibration and adjustment in the process. For example, for a sine wave, we can set multiple correction points in the half-wave or 1 / 4-wave band, such as setting multiple correction points 3, 4, 5, 6, etc., so as to achieve precise correction of the drive current. This allows the drive chip to output precise drive energy and achieve the goal of efficient and accurate drive of the drive circuit. In specific work, an OR operation can be set between two points to determine the relative interval time between the two points. It is not limited to which two specific points are ORed.

[0050] Figure 5 This is a schematic diagram of a modular chip provided in an embodiment of the present invention; the laser source is optimally selected as a diode-type light source, such as a vertical cavity surface diode emitter (VCSEL). The driving module needs to output accurate driving power according to the optical characteristics requirements such as the power beam waveform. For example, for a traditional trapezoidal pulse wave, accurately obtaining the rise and fall times of the waveform becomes crucial. Figure 3 The APC calibration described herein obtains the current requirement corresponding to the target waveform, and then the actual current is fed into the drive circuit module in the form of feedback. In this way, the entire drive chip has the function of automatically calibrating and correcting the emitted light. Thus, the system does not require an external sampling device to accurately locate the rise and fall times of the converted current, ensuring that the waveform emitted by the laser source driven by the entire drive chip is always accurate.

[0051] Figure 6 This is a schematic diagram illustrating the storage of time information acquired by a Time Control Controller (TDC) according to an embodiment of the present invention. After the TDC measures the rising edge, falling edge, or other wave calibration time period information, the measurement result needs to be stored. Here, we take connecting a register REG after the TDC as an example, and taking an 8-bit TDC output as an example, when the TDC outputs the rising edge time, it outputs a converted 8-bit binary code segment. The register also receives this 8-bit storage code segment. Of course, the register can further include an identification information code segment; this is not limited here. For example, it can... Figure 3 Based on the obtained information, the precise rise time and fall time can be obtained by following the formulas Tr = t1 - t0, Tf = t3 - t2, and T = t2 - t0.

[0052] Figure 7This is a schematic diagram of a circuit operation implementation provided in an embodiment of the present invention. Through APC calibration, the current magnitude Itarget corresponding to the target optical power is obtained, that is, the target optical waveform is converted into current demand. The threshold setting of the two sampling circuits is achieved by adjusting the resistance value of the variable resistor. The target waveform includes a rising edge stage and a falling edge stage. Therefore, in order to accurately drive the light-emitting unit to output the correct waveform, it is necessary to accurately obtain the rising edge and falling edge times. When the threshold of the first sampling circuit is reached, the switching module 1buffer1 outputs a high level. At this time, the second threshold has not yet been reached, so the result of the XOR operation by the operation unit will be true. At this time, the subsequent circuit works, that is, the TDC starts counting. As time increases, the threshold of the second sampling circuit is also reached. At this time, the XOR operation by the operation module can obtain a false result of 0. At this time, the counter will stop working. In this way, the rising edge time is obtained. Obtaining the falling edge time is similar to obtaining the rising edge time, and will not be described in detail here.

[0053] Figure 8 This is a schematic diagram of a sine wave drive implemented using the present invention, provided as an embodiment of the present invention. Here, six sampling points are set within a 1 / 4 wavelength range as an example. However, the 0 point is generally not calibrated, so five points are actually required for sampling. A current mirror or similar device is used to replicate multiple signals, and then an XOR operation is performed on any two signals to determine multiple relative time information. The obtained time information can be used to complete the calibration of the drive device. It is not limited here; five or more sampling points can also be set in half a wave period to complete the calibration.

[0054] Figure 9 This is a schematic diagram provided by an embodiment of the present invention, which can be used to accurately obtain the rising and falling edge times in TOF ranging to correct the ranging accuracy. During the ranging process, there is also a phenomenon that the ranging has a certain error due to the uncertainty of the rising or falling edge. Therefore, for scenarios that require high-precision detection, using a similar principle of the present invention to obtain accurate rising and / or falling edge times and complete the calibration of accurate detection is also an application of the present invention. The acquisition principle will not be described in detail here.

[0055] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0056] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need further definition and explanation in subsequent figures. The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A driving circuit, characterized in that, include: The target waveform conversion unit is used to convert target waveform information into current or voltage signals. The converted current or voltage signal is output to the first sampling circuit and the second sampling circuit; the arithmetic module outputs an action command according to the output results of the first sampling circuit and the second sampling circuit; the TDC module outputs the time parameter of the counting interval according to the action command output by the arithmetic module. The current or voltage signal after the target waveform is converted includes a rising edge and a falling edge, and the time parameter of the counting interval output by the TDC module is at least a portion of the total time of the rising edge and / or the falling edge.

2. The driving circuit according to claim 1, characterized in that, The first sampling circuit has a first output threshold, the second sampling circuit has a second output threshold, and the first output threshold is less than the second output threshold.

3. The driving circuit according to claim 2, characterized in that, The arithmetic module includes a first switching module and a second switching module. When the first sampling circuit reaches a first output threshold, the level of the first switching module switches; when the second sampling circuit reaches a second output threshold, the level of the second switching module switches.

4. The driving circuit according to claim 1, characterized in that, The arithmetic module includes an XOR operation unit, which outputs an action command based on the output results of the first sampling circuit and the second sampling circuit.

5. The driving circuit according to claim 1, characterized in that, The TDC module has picosecond-level accuracy.

6. The driving circuit according to claim 2, characterized in that, It also includes a first output threshold and a second output threshold adjustment module, wherein the first output threshold and the second output threshold adjustment module include an adjustable resistor, the value of which determines the first output threshold and the second output threshold.

7. The driving circuit according to claim 6, characterized in that, The adjustable resistance value of the threshold adjustment module is adjusted in at least one of the following ways: power-on calibration, preset time period adjustment, or adaptive adjustment.

8. The driving circuit according to claim 1, characterized in that, It also includes a latching module, which latches the time parameters of the counting interval output by the TDC module according to the action instructions output by the arithmetic module.

9. A driving method implemented using the driving circuit of claim 1, characterized in that, include: The target waveform conversion unit is used to convert target waveform information into current or voltage signals. The converted current or voltage signal is output to the first sampling circuit and the second sampling circuit; the arithmetic module outputs an action command according to the output results of the first sampling circuit and the second sampling circuit; the TDC module outputs the time parameter of the counting interval according to the action command output by the arithmetic module. The current or voltage signal after the target waveform is converted includes a rising edge and a falling edge, and the time parameter of the counting interval output by the TDC module is at least a portion of the total time of the rising edge and / or the falling edge.

10. The driving method according to claim 9, characterized in that, The first sampling circuit has a first output threshold, the second sampling circuit has a second output threshold, and the first output threshold is less than the second output threshold.

11. The driving method according to claim 9, characterized in that, The arithmetic module includes an XOR operation unit, which outputs an action command based on the output results of the first sampling circuit and the second sampling circuit.

12. The driving method according to claim 10, characterized in that, It also includes a first output threshold and a second output threshold adjustment module, wherein the first output threshold and the second output threshold adjustment module include an adjustable resistor, the value of which determines the first output threshold and the second output threshold.

13. The driving method according to claim 9, characterized in that, It also includes a latching module, which latches the time parameters of the counting interval output by the TDC module according to the action instructions output by the arithmetic module.

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