A drive circuit and method

Abstract

The application provides a driving circuit and a circuit driving method, characterized by comprising: a current output module, which outputs different current values; a first adjustable resistor, which determines a first adjustable resistor value according to a first current threshold value output by the current module; and a second adjustable resistor, which determines a second adjustable resistor value according to a second current threshold value output by the current module. Thus, the application can be used for calibrating emission or final ranging results in a time-of-flight ranging scheme, so that the emission source emits a more accurate light waveform or the ranging result is more accurate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of driving circuit, in particular, to a driving circuit and a driving method. BACKGROUND

[0002] Due to one or more external influences, the rise / fall time of signals propagating between a CPU and a chipset will typically vary. These influences include variations in silicon strength caused by process, voltage and / or temperature conditions present on the large die. Uncompensated power supply voltage variations can also cause rise / fall time variations. If left unaddressed, these variations will have an adverse impact on system performance. For example, if the rise / fall time is too slow, timing faults can occur. Conversely, if the rise / fall time is too fast, signal integrity and reliability problems can arise due to large reflections and overshoot / undershoot effects. For active light source detection type systems, such as laser light source based ranging systems, driving the laser source to emit a specific waveform is critical to detection, however, whether the waveform is accurate depends largely on the accurate control of the rise time and the fall time.

[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., "0" to "1"), and fall time is the time it takes to transition from a high logic level to a low logic level (e.g., "1" to "0"). Knowing the rise and fall times of a pulse (the rising and falling edges) is fundamental to the use of pulses in measurement and test applications. The degree to which the rise and / or fall times of a pulse affect the performance of the device under test depends on the nature of the device and the type of test being performed.

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

[0005] One disadvantage of this solution is the need for an oscilloscope (extra cost) and an automatic test controller (specialized computer and software) or a well-trained operator. A second disadvantage is that the operation of the rise and fall time circuit can be affected by operating temperature or component aging and can require continuous or frequent calibration. If relatively complex measurements or procedures are required to adjust for these effects, the user can find the adjustment inconvenient and operate the instrument under less than ideal conditions.

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

[0007] In order to solve the above problems, it is urgent to provide a waveform capable of quickly and accurately determining the accurate operation of the driven light source, to realize an accurate detection circuit and method, and to realize integration with the transmitting end drive, to realize a laser transmitting end with self-detection, calibration and correction. SUMMARY

[0008] The purpose of the present application is to provide a driving circuit and driving method to solve the problem of the related art that the transmitting end waveform cannot be accurately controlled or the ranging result cannot be more accurate.

[0009] To achieve the above purpose, the technical solutions adopted by the embodiments of the present application are as follows:

[0010] In a first aspect, the embodiments of the present application provide a driving circuit, comprising: a current output module, the current output module outputs different current values;

[0011] a first adjustable resistor, the first adjustable resistor value is determined according to the first current threshold value output by the current module;

[0012] a second adjustable resistor, the second adjustable resistor value is determined according to the second current threshold value output by the current module.

[0013] Optionally, the current output module is an IDAC (current digital-to-analog converter).

[0014] Optionally, the first current threshold value is less than the second current threshold value.

[0015] Optionally, the driving circuit further comprises a first switch and a second switch.

[0016] Optionally, when the first switch is closed, the first adjustable resistor value is determined according to the first current threshold value output by the current output module; when the second switch is closed, the second adjustable resistor value is determined according to the second current threshold value output by the current output module.

[0017] Optionally, the driving circuit further comprises a first inversion module and / or a second inversion module.

[0018] Optionally, the first jump module and / or the second jump module is an even number of inverters.

[0019] Optionally, when the current module outputs the first current threshold value, the first adjustable resistor value is adjusted until the level of the first jump module jumps, and the first adjustable resistor value is determined; when the current module outputs the second current threshold value, the second adjustable resistor value is adjusted until the level of the second jump module jumps, and the second adjustable resistor value is determined.

[0020] Secondly, embodiments of this application provide a circuit driving method applied to the driving circuit described in the first aspect above, the circuit driving method comprising:

[0021] Determine the first current threshold;

[0022] Determine the second current threshold;

[0023] The first adjustable resistance value is determined based on the first current threshold.

[0024] The second adjustable resistor value is determined based on the second current threshold.

[0025] Optionally, the first switch is closed when the first adjustable resistance value is determined; the second switch is closed when the second adjustable resistance value is determined.

[0026] Optionally, the first current threshold is less than the second circuit threshold.

[0027] Optionally, the first adjustable resistor value can be determined by adjusting the first adjustable resistor value according to the determined first current threshold until the level of the first switching module changes; the second adjustable resistor value can be determined by adjusting the second adjustable resistor value according to the determined second current threshold until the level of the second switching module changes.

[0028] The beneficial effects of this application are:

[0029] This application provides a driving circuit and a circuit driving method. The driving circuit includes a current output module, which outputs different current values.

[0030] The first adjustable resistor is determined based on the first current threshold value output by the current module.

[0031] The second adjustable resistor is determined based on the second current threshold value output by the current module.

[0032] This invention can determine the value of an adjustable resistor by setting a current threshold. The determined resistance value is used in subsequent waveform calibration and determination. Compared with traditional circuits, it does not use a reference signal or a comparator design, which ensures the simplicity, efficiency and feasibility of the circuit. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, 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 this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 A schematic diagram of a driving circuit provided in an embodiment of this application;

[0035] Figure 2 A schematic diagram of another sensor provided in an embodiment of this application;

[0036] Figure 3 A schematic diagram of a modular chip provided in an embodiment of this application;

[0037] Figure 4 A flowchart of another circuit driving method provided in an embodiment of this application;

[0038] Figure 5 This is a schematic flowchart of a circuit driving method provided in this application. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0041] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0042] Figure 1 This is a schematic diagram of a driving circuit provided in an embodiment of this application. Figure 1The diagram shown is a schematic of a driving circuit provided by an embodiment of the present invention. In the implementation scheme provided by the present invention, the driven system is an active laser source detection system. The waveform is a light wave. The waveform conversion module can be used to obtain the power requirement for driving the laser through the waveform requirement, and then convert the power requirement into a current requirement. Here, the converted waveform micro-current waveform is used as an example for explanation. However, 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, the same current can be divided into several different paths by using a current mirror. This realizes the mirror copy of the current signal. Due to this feature, the mirrored current can be directly used without using an additional resistor to convert it into voltage, which simplifies 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 traditional complex implementation schemes such as using ramp comparison signals or comparators. The current here is from two paths, taking 20% ​​and 80% of the target current as examples. In the first circuit, resistor R1 is set so that the switching module jumps at 20% of the highest current value. The switching module can be an even number of inverters. The IDAC first outputs 20% of the target current as the first current threshold. Then, switch S1 is closed, and the value of adjustable resistor R1 is adjusted so that the output of buffer1 jumps at the value of R1, which is the value used later in calibration and waveform determination. Similarly, the IDAC outputs 80% of the target current as the second current threshold. Then, switch S2 is closed, and the value of adjustable resistor R2 is adjusted so that the output of buffer2 jumps at the value of R2, which is the value used later in calibration and waveform determination. The switching module can also be an even number of inverters. This is just one example and does not limit the specific module implementation. The two switching modules are... Figure 1 buffer1 and buffer2 in the middle.

[0043] Figure 2The schematic diagram of another driving circuit provided in this application shows that the current magnitude Itarget corresponding to the target optical power can be obtained through APC calibration. Based on Itarget, 0.2Itarget and 0.8Itarget are calculated. First, the resistance value of the adjustable resistor is adjusted. Here, 80% and 20% are used as examples. With S1 closed, 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, and IDAC is adjusted... Adjust the R2 resistor (from small to large) to 0.8Itarget / 1000. When the output of buffer2 changes from low to high, stop the adjustment of R2 through EN2 and maintain the current output value of R2. Through this adjustment step, the resistance value of the adjustable resistor can be confirmed under low current, ensuring that the energy consumption is small during the entire 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: Open S2, close S0. 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, the XOR output goes high, TDC is started and counting begins; this moment is recorded as t0. When the sampling current rises to 0.8Itarget / 1000, the output of buffer2 changes from low to high, 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, the current first drops to 0.8Itarget / 1000. When buffer2 outputs a low level and XOR outputs a high level, this moment is recorded as t2. When the current drops to 0.2Itarget / 1000, buffer1 outputs a low level and XOR outputs a low level, this moment is recorded as t3. TDC is stopped and the counting result is latched into the register. This is described from the perspective of the driving scheme within the driver chip. Of course, the above thresholds are not limited to 20% and 80%. Threshold calibration can also be arranged in different time periods, such as power-on calibration before power-on, fixed time or random time period during device operation, or adaptive time period arrangement during use, such as adaptive calibration during the interval of the drive power supply. This is not limited here.

[0044] Figure 3This application provides a schematic diagram of a modular chip design. The laser source is optimally selected as a diode-type light source, such as a vertical-cavity surface-mount diode emitter (VCSEL). The driving module needs to output accurate driving power according to optical characteristics 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 2 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.

[0045] Figure 4 A schematic diagram of a driving circuit provided in this application, and Figure 2 The difference in this embodiment is that the adjustable resistors are not limited to 2 channels, but can be N channels, where N is greater than or equal to 1. This embodiment is... Figure 2 An extended case of the provided implementation series, the principle for determining each adjustable resistor and Figure 2 The implementation follows the same principle, so it will not be repeated here.

[0046] Figure 5 This is a flowchart illustrating a circuit driving method provided in this application. This method can be applied to the aforementioned driving circuit. The basic principle and technical effects of this method are the same as those in the corresponding driving circuit embodiments described above. For the sake of brevity, parts not mentioned in this embodiment can be referred to the corresponding content in the driving circuit embodiments. Figure 5 As shown, the circuit driving method includes:

[0047] S101. Determine the first current threshold.

[0048] S102, Determine the second current threshold.

[0049] S103. Determine the first adjustable resistance value based on the first current threshold.

[0050] S104. Determine the second adjustable resistor value based on the second current threshold.

[0051] Optionally, the first switch is closed when the first adjustable resistance value is determined; the second switch is closed when the second adjustable resistance value is determined.

[0052] Optionally, the first current threshold is less than the second circuit threshold.

[0053] Optionally, the first adjustable resistor value can be determined by adjusting the first adjustable resistor value according to the determined first current threshold until the level of the first switching module changes; the second adjustable resistor value can be determined by adjusting the second adjustable resistor value according to the determined second current threshold until the level of the second switching module changes.

[0054] The above method is applied to the driving circuit provided in the foregoing embodiments, and its implementation principle and technical effect are similar, so it will not be described again 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 drive circuit characterized by comprising: The application relates to a driving circuit and a method for determining a first adjustable resistance value and a second adjustable resistance value. The driving circuit comprises: a current output module outputting different current values; a first adjustable resistance, a first adjustable resistance value being determined according to a first current threshold value outputted by the current output module; and a second adjustable resistance, a second adjustable resistance value being determined according to a second current threshold value outputted by the current output module; the driving circuit further comprises a first jump module and a second jump module. When the current output module outputs the first current threshold value, the first adjustable resistance value is adjusted until the level of the first jump module jumps, and the first adjustable resistance value is determined. When the current output module outputs the second current threshold value, the second adjustable resistance value is adjusted until the level of the second jump module jumps, and the second adjustable resistance value is determined. The current output module is an IDAC (current digital-to-analog converter). The first current threshold value is smaller than the second current threshold value.

2. The drive circuit according to claim 1, characterized by The driving circuit further comprises a first switch and a second switch.

3. The drive circuit according to claim 1, characterized by When the first switch is closed, the first adjustable resistance value is determined according to the first current threshold value outputted by the current output module; and when the second switch is closed, the second adjustable resistance value is determined according to the second current threshold value outputted by the current output module.

4. The drive circuit according to claim 1, characterized by The first jump module and / or the second jump module are even-numbered inverters.

5. The drive circuit according to claim 4, characterized in that, The method is applied to the driving circuit of claim 1, and the method comprises the following steps: determining a first current threshold value; determining a second current threshold value; determining a first adjustable resistance value according to the first current threshold value; and determining a second adjustable resistance value according to the second current threshold value.

6. The drive circuit of claim 1, wherein The first adjustable resistance value is adjusted according to the determined first current threshold value until the level of the first jump module jumps, and the first adjustable resistance value is determined; and the second adjustable resistance value is adjusted according to the determined second current threshold value until the level of the second jump module jumps, and the second adjustable resistance value is determined.

7. A circuit driving method, characterized by, The first switch is closed when the first adjustable resistance value is determined; and the second switch is closed when the second adjustable resistance value is determined. The first current threshold value is smaller than the second current threshold value.

8. The circuit driving method according to claim 7, wherein ​ 9. The circuit driving method according to claim 7, wherein ​

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