CN114122891A

CN114122891A - Driving circuit and method

Info

Publication number: CN114122891A
Application number: CN202010895358.0A
Authority: CN
Inventors: 雷述宇
Original assignee: Ningbo Abax Sensing Electronic Technology Co Ltd
Current assignee: Ningbo Abax Sensing Electronic Technology Co Ltd
Priority date: 2020-08-31
Filing date: 2020-08-31
Publication date: 2022-03-01

Abstract

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

Description

Driving circuit and method

Technical Field

The invention relates to the field of driving circuits, in particular to a driving circuit and a driving method.

Background

The rise/fall times of signals propagating between the CPU and the chipset typically vary due to one or more external influences. These effects include variations in silicon strength caused by process, voltage and/or temperature conditions present on a large number of die. Uncompensated supply voltage variations can also result in rise/fall time variations. These variations, if not addressed, can adversely affect system performance. For example, if the rise/fall time is too slow, a timing failure 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, and for active light source detection type systems, such as ranging systems with a laser as the light source, driving the laser source to emit a wave of a particular waveform is critical to detection, however whether the waveform is accurate depends largely on the accurate control of the rise and fall times.

The rise time refers to the time for the digital logic circuit to transition from a low logic level to a high logic level (e.g., "0" to "1"), and the fall time is the time required to transition from a high logic level to a low logic level (e.g., "1" to "0"). It is necessary to know that pulse rise and fall times (rising and falling edges) are within specification as the basis for using pulses in measurement and test applications. The extent to which pulse rise and/or fall times affect a desired device under test performance depends on the nature of the device and the type of test to be performed.

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 equipment typically requires pulse rise and fall time verification to be performed using an external oscilloscope and an automatic test equipment controller or a trained operator.

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

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

In order to solve the above problems, there is a need for a laser emitting terminal capable of quickly and accurately determining the waveform of the driven light source to accurately operate, so as to implement a precise detection circuit and method, and capable of being integrated with the emitting terminal drive to implement self-detection and calibration correction.

Disclosure of Invention

The present invention is directed to provide a driving circuit and a driving method for solving the above-mentioned shortcomings of the prior art, so as to solve the problem in the related art that precise control of the waveform of the transmitting terminal is not possible or the ranging result cannot achieve more precise output.

In order to achieve the above purpose, the embodiment of the present invention adopts the following technical solutions:

in a first aspect, an embodiment of the present application provides a driving circuit, including: the current output module outputs different current values;

a first adjustable resistance value determined according to a first current threshold output by the current module;

a second adjustable resistance value determined from a second current threshold output by the current module.

Optionally, the current output module is a current digital-to-analog converter (IDAC).

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

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

Optionally, when the first switch is closed, determining a first adjustable resistance value according to a first current threshold output by the current output module; and when the second switch is closed, determining a second adjustable resistance value according to a second current threshold value output by the current output module.

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

Optionally, the first transition module and/or the second transition module is an even number of inverters.

Optionally, when the current module outputs the first current threshold, the first adjustable resistance value may be determined by adjusting the first adjustable resistance value until the level of the first transition module transitions; and when the current module outputs a second current threshold value, adjusting a second adjustable resistance value until the level of the second jump module jumps, and determining the second adjustable resistance value.

In a second aspect, an embodiment of the present application provides a circuit driving method, which is applied to the driving circuit described in the first aspect, and the circuit driving method includes:

determining a first current threshold;

determining a second current threshold;

determining a first adjustable resistance value according to the first current threshold value;

a second adjustable resistance value is determined based on the second current threshold.

Optionally, closing the first switch when the first adjustable resistance value is determined; and closing the second switch when the second adjustable resistance value is determined.

Optionally, the first adjustable resistance value is adjusted according to the determined first current threshold value until the level of the first jump module jumps, so that the first adjustable resistance value can be determined; and adjusting the second adjustable resistance value according to the determined second current threshold value until the level of the second jumping module jumps, so that the second adjustable resistance value can be determined.

The beneficial effect of this application is:

the embodiment of the application provides a driving circuit and a circuit driving method, wherein the driving circuit comprises: the current output module outputs different current values;

The invention can determine the value of the adjustable resistor through the set current threshold, the determined resistance value is used for subsequent waveform calibration and determination, and compared with the traditional circuit, the invention does not use reference or reference signals and adopts a comparator design to ensure the simplicity and the high efficiency of the circuit and the stronger realizability of the circuit.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 is a schematic diagram of a driving circuit according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of another sensor provided in embodiments of the present application;

fig. 3 is a schematic diagram of a chip module according to an embodiment of the present disclosure;

fig. 4 is a flowchart of another circuit driving method according to an embodiment of the present disclosure;

fig. 5 is a schematic flowchart of a circuit driving method provided in the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

Fig. 1 is a schematic diagram of a driving circuit according to an embodiment of the present disclosure. Fig. 1 is a schematic structural diagram of a driving circuit according to an embodiment of the present invention, in an implementation scheme provided by the present invention, a system driven for active laser source detection is taken as an example, where a waveform is an optical wave requirement, a power requirement of laser driving operation can be obtained through a waveform conversion module, for example, from the waveform requirement, and then the power requirement is converted into a current requirement, where a converted waveform micro-current waveform is taken as an example for description, but an actual implementation is not limited to a current, and a voltage can also be used, where a current is taken as an example, and an effect of easy implementation is provided, for example, a current mirror can be used to divide the same current into different circuits, so that mirror copy of a current signal is achieved, and also because of this characteristic, a current directly using mirror image can be converted into a voltage without using an additional resistor, a circuit is simplified, in addition, the copied multipath current also provides a premise for setting different thresholds for the currents of different circuits, and the traditional complex implementation scheme of using a ramp comparison signal or a comparator and the like can be omitted. The current is two-way, here, taking 20% of the target current and 80% of the target current as an example, the resistance of the first circuit R1 is set according to the value that the jump module jumps at 20% of the highest current, where the jump module may be an even number of inverters, the IDAC first outputs 20% of the target current as the first current threshold, then closes the switch S1, and adjusts the value of the adjustable resistor R1 so that the value at the time R1 when the output of the buffer1 jumps is the value used subsequently in calibrating and determining the waveform. Similarly, 80% of the IDAC output target current is used as the second current threshold, then the switch S2 is closed, and the value of the adjustable resistor R2 is adjusted so that the value of R2 at the time when the output of buffer2 makes a transition is the value used in calibrating and determining the waveform, where the transition module may be an even number of inverters, which is also an example and not limited to a specific module implementation, and the two transition modules are buffer1 and buffer2 in fig. 1.

FIG. 2 is a schematic structural diagram of another driving circuit provided in the present application, which can obtain a current magnitude Itarget corresponding to a target optical power through APC calibration; calculating 0.2Itarget and 0.8Itarget according to Itarget, firstly adjusting the resistance value of an adjustable resistor, taking 80% and 20% as examples, closing S1, adjusting IDAC to 0.2Itarget/1000 (Isense to Itarget gain is 1000 in circuit design), adjusting R1 resistor (from small to large), stopping the adjustment of R1 through EN1 when buffer1 output jumps from low level to high level, and keeping the current output value of R1, similarly, opening S1, closing S2, adjusting IDAC to 0.8Itarget/1000, adjusting R2 resistor (from small to large), stopping the adjustment of R2 through EN2 when buffer2 outputs low level jumps to high level, and keeping the current output value of R2, and by this adjusting step, the confirmation of the adjustable resistor at low current is realized, the resistance value adjustment is ensured, and the whole driving process is also small and reasonable. After the resistance of the variable resistor is held fixed, the circuit may operate by turning off S2, closing S0, the Sensor driving the Driver chip via LVDS, jumping from low to high at buffer1 output when the sampling current rises to 0.2Itarget/1000, XOR outputting high, starting TDC and starting counting, denoted t0, jumping from low to high at buffer2 output when the sampling current rises to 0.8Itarget/1000, XOR outputting low at t1, latching the counter data into the register, similarly, for the falling edge, first falling to 0.8Itarget/1000, outputting low at buffer1, outputting high at XOR 5634, denoted t2, and then falling to 0.2Itarget/1000, outputting low at buffer1, stopping the XOR output, and stopping counting at 3, the description is made in terms of a driving scheme in a driving chip, and of course, the threshold is not limited to be a fixed 20% or 80%, and the correction of the threshold may also be arranged in different time periods, for example, a power-on calibration is performed before power-on, a fixed time or a random time period may be selected during the operation of the device, or an adaptive time period may be arranged during the use, for example, an adaptive calibration is arranged in a gap between the use time periods of the driving power supply, which is not limited herein.

Fig. 3 is a schematic diagram of a chip module according to an embodiment of the present disclosure; the laser source is optimally selected to be a diode type light emitting source, for example, the laser source can be a vertical cavity surface diode emitter VCSEL, the driving module needs to output accurate driving power according to optical characteristics of a power optical waveform and the like, for example, for a traditional trapezoidal pulse wave, it becomes important to accurately obtain rising edge and falling edge time of the waveform, for example, the APC calibration illustrated in fig. 2 is used to obtain a current requirement corresponding to a target waveform, and then an actual current is connected to the driving circuit module in a feedback form, so that the whole driving chip has a function of automatically calibrating and correcting emitted light, so that the system does not need an external separate sampling device to accurately position converted rising edge and falling edge time of the current, and the waveform emitted by the laser source driven by the whole driving chip is always in an accurate effect.

Fig. 4 is a schematic diagram of a driving circuit provided in the present application, and the difference from the embodiment of fig. 2 is that the adjustable resistor of the embodiment is not limited to 2 paths, and may be N paths, where N is greater than or equal to 1. This embodiment is an extension of the embodiment provided in fig. 2, and the determination principle of each adjustable resistor is the same as that provided in the embodiment of fig. 2, and will not be described here again.

Fig. 5 is a schematic flowchart of a circuit driving method provided in the present application. The method can be applied to the aforementioned driving circuit, the basic principle and the technical effect of the method are the same as those of the aforementioned corresponding driving circuit embodiment, and for the sake of brief description, no part is mentioned in this embodiment, and reference may be made to the corresponding contents in the driving circuit embodiment. As shown in fig. 5, the circuit driving method includes:

s101, determining a first current threshold.

And S102, determining a second current threshold.

And S103, determining a first adjustable resistance value according to the first current threshold value.

And S104, determining a second adjustable resistance value according to the second current threshold value.

The method is applied to the driving circuit provided in the foregoing embodiment, and the implementation principle and the technical effect are similar, which are not described herein again.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A driver circuit, comprising: the current output module outputs different current values;

2. The driving circuit of claim 1, wherein the current output module is a current digital-to-analog converter (IDAC).

3. The driver circuit of claim 1, wherein the first current threshold is less than the second circuit threshold.

4. The driving circuit of claim 1, further comprising a first switch and a second switch.

5. The driving circuit of claim 1, wherein when the first switch is closed, a first adjustable resistance value is determined according to a first current threshold output by the current output module; and when the second switch is closed, determining a second adjustable resistance value according to a second current threshold value output by the current output module.

6. The driving circuit according to claim 1, further comprising a first inversion module and/or a second inversion module.

7. The driving circuit of claim 6, wherein the first transition module and ∑ is

Or the second jumping module is an even number of inverters.

8. The driving circuit of claim 1, wherein when the current module outputs the first current threshold, the first adjustable resistance value is determined by adjusting the first adjustable resistance value until a level of the first transition module transitions; and when the current module outputs a second current threshold value, adjusting a second adjustable resistance value until the level of the second jump module jumps, and determining the second adjustable resistance value.

9. A circuit driving method applied to the driving circuit of claim 1, the method comprising:

determining a first current threshold;

determining a second current threshold;

10. The circuit driving method according to claim 10, wherein the first switch is closed when the first adjustable resistance value is determined; and closing the second switch when the second adjustable resistance value is determined.

11. The circuit driving method according to claim 10, wherein the first current threshold is smaller than the second circuit threshold.

12. The circuit driving method as claimed in claim 10, wherein the first adjustable resistance value is determined by adjusting the first adjustable resistance value according to the determined first current threshold value until a level of the first transition module transitions; and adjusting the second adjustable resistance value according to the determined second current threshold value until the level of the second jumping module jumps, so that the second adjustable resistance value can be determined.