Drive circuit for single photon detector, receiver for lidar, and lidar

Abstract

The utility model provides a driving circuit for a single photon detector, a receiver for a lidar, and the lidar. The driving circuit includes: a regulation circuit configured to receive an input voltage and output a first voltage; a gradual changing circuit electrically coupled with the adjusting circuit and electrically coupled with a first end of a single-photon detector, the gradual changing circuit being configured to receive the first voltage and provide a second voltage at the first end of the single-photon detector; wherein the impedance of the slow varying circuit to a high-frequency signal is greater than that of the slow varying circuit to a low-frequency signal, and the slow varying circuit is configured to enable the duration of the current in the single-photon detector greater than a first current threshold value to be less than or equal to a first time threshold value.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of laser detection, and more particularly, to a driving circuit for a single photon detector, a receiver for a laser radar, and a laser radar. BACKGROUND

[0002] A single photon detector (SPAD) is an optical detector with extremely high sensitivity, which can be used to achieve a response to a single photon. When a SPAD is used in a laser ranging or laser radar (LiDAR) application, if the detected object is a high-reflectivity material (e.g., a traffic sign), the intensity of the light reflected back by the object is large, and the number of photons received by the SPAD increases. The SPAD generates an avalanche current when a photon is detected, and when the intensity of the light reflected back by the object is large, the instantaneous current through the SPAD can be large. As a result, the ground voltage at different positions on the circuit board fluctuates (also known as "ground bounce"), which can cause some circuits or devices on the circuit board to malfunction. SUMMARY

[0003] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the present disclosure, as claimed.

[0004] According to an aspect of the present disclosure, a driving circuit for a single photon detector is provided. The driving circuit comprises: a regulating circuit configured to receive an input voltage and output a first voltage; a ramping circuit electrically coupled with the regulating circuit and electrically coupled with a first terminal of the single photon detector, the ramping circuit configured to receive the first voltage and provide a second voltage at the first terminal of the single photon detector; wherein an impedance of the ramping circuit to a high frequency signal is greater than an impedance to a low frequency signal, and the ramping circuit is configured to cause a duration in which a current in the single photon detector is greater than a first current threshold to be less than or equal to a first time threshold.

[0005] Optionally, the ramping circuit comprises: an inductive component electrically coupled between the regulating circuit and the first terminal of the single photon detector; a capacitive component electrically coupled to the first terminal of the single photon detector.

[0006] Optionally, the capacitive component comprises a capacitor.

[0007] Optionally, the inductive component comprises a resistor and an inductor connected in series.

[0008] Optionally, a quality factor of the ramping circuit is less than a second threshold.

[0009] Optionally, the time constant of the ramping circuit is less than a third threshold.

[0010] Optionally, the equivalent capacitance value of the capacitive component is less than a fourth threshold.

[0011] Optionally, the regulating circuit comprises: a voltage transformer electrically coupled between the input voltage and the ramping circuit; and a second capacitive component electrically coupled to a node between the voltage transformer and the ramping circuit, wherein the regulating circuit is configured to output the first voltage at the node.

[0012] Optionally, the voltage transformer comprises a BOOST converter.

[0013] Optionally, the driving circuit further comprises a readout circuit electrically coupled to the second end of the single-photon detector.

[0014] According to another aspect of the present disclosure, there is provided a receiver for a lidar. The receiver comprises: one or more single-photon detectors; and a driving circuit as described above.

[0015] Optionally, the single-photon detector comprises a photoactive element and a quenching element.

[0016] According to another aspect of the present disclosure, there is provided a lidar. The lidar comprises a receiver as described above. BRIEF DESCRIPTION OF DRAWINGS

[0017] The present disclosure can be better understood with reference to the following examples in conjunction with the accompanying drawings, in which:

[0018] Figure 1A and Figure 1A respectively show a schematic diagram of a connection of a driving circuit for a single-photon detector;

[0019] Figure 2 shows a block diagram of a driving circuit for a single-photon detector of a first exemplary embodiment consistent with some embodiments of the present disclosure;

[0020] Figure 3 shows a block diagram of a driving circuit for a single-photon detector of a second exemplary embodiment consistent with some embodiments of the present disclosure;

[0021] Figure 4 shows a block diagram of a driving circuit for a single-photon detector of a third exemplary embodiment consistent with some embodiments of the present disclosure;

[0022] Figure 5A block diagram of a drive circuit for a single-photon detector is shown, in accordance with some embodiments of the present disclosure, for a fourth example embodiment;

[0023] Figure 6 A schematic diagram of connections of a drive circuit for a single-photon detector is shown, in accordance with some embodiments of the present disclosure, for a first example embodiment;

[0024] Figure 7 A schematic diagram of connections of a drive circuit for a single-photon detector is shown, in accordance with some embodiments of the present disclosure, for a second example embodiment;

[0025] Figure 8 A schematic diagram of a receiver for a lidar is shown, in accordance with some embodiments of the present disclosure; and

[0026] Figure 9 A schematic diagram of a lidar is shown, in accordance with some embodiments of the present disclosure. DETAILED DESCRIPTION

[0027] Embodiments of the present disclosure will be described below. It is to be noted that in the following description, for the sake of brevity, certain embodiments of the disclosure are outlined in broadest terms so as to not obscure the disclosure fully. Each of the embodiments disclosed is briefly described as being composed of several aspects or elements in a specific combination. It is to be noted that these aspects and elements can, by themselves, exist in multiple embodiments and each such embodiment can be utilized independently of the other embodiments. Or certain features of the disclosure can be applied to some embodiments and not others. It is to be understood that the description and specific examples are intended for the purposes of illustration only and are not intended to limit the scope of the present disclosure.

[0028] Unless otherwise defined, technical and scientific terms used in the claims and specification have their ordinary meaning as understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first", "second", and similar terms do not imply any order, quantity, or importance, but are used to distinguish one element from another, and the terms "a" and "an" and "the" and similar terms mean "one or more", unless otherwise specifically stated. The terms "including", "comprising" and similar terms are used synonymously with "comprising" to mean that the product, process, method, or apparatus includes the recited elements, but not excluding others. The term "coupled" and related terms such as "coupling" or "coupled to" are used herein to express that two or more elements are connected together in some form, whether directly or indirectly, physically or logically, and whether through one or more elements.

[0029] In the present disclosure, unless otherwise specified, all embodiments mentioned herein can be combined with each other to form a new technical solution. In the present disclosure, unless otherwise specified, all technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0030] In the present disclosure, the terms "or" and "and / or" describe the association relationship between related objects and represent a non-exclusive inclusion. For example, "A and / or B" and "A or B" may include: only "A" exists, only "B" exists, and "A" and "B" exist at the same time, where "A" and "B" can be singular or plural. For another example, "A, B and / or C" and "A, B or C" may include: only "A" exists, only "B" exists, only "C" exists, "A" and "B" exist at the same time, "A" and "C" exist at the same time, "B" and "C" exist at the same time, and "A", "B" and "C" exist at the same time, where "A", "B" and "C" can be singular or plural. In addition, the symbol " / " in the present disclosure indicates that there is an "or" relationship between the related objects before and after the symbol. In the present disclosure, the term "at least one A or B" has the same meaning as the above-mentioned "A or B". The term "at least one A, B or C" has the same meaning as the above-mentioned "A, B or C".

[0031] Figure 1A A schematic diagram showing the connection of a driving circuit for a single photon detector is shown. Figure 1A In the SPAD driving circuit shown, the single-photon detector D1 receives the echo reflected by the object and generates a current in the circuit. Due to the presence of parasitic resistance in the circuit, the voltage at one end of the capacitor C1 connected to the ground wire rises, which in turn causes the output voltage NHV at one end of the capacitor C1 connected to the single-photon detector D1 to rise, causing the voltage difference across the single-photon detector D1 to decrease, and the photon detection efficiency (PDE) of the single-photon detector D1 to decrease. When NHV rises, the BOOST circuit can adjust the output voltage NHV to restore NHV to a normal value. However, when the echo reflected by the object is very strong, a large current will be generated in the circuit, and the NHV negative voltage may rise significantly. The BOOST circuit has limited adjustment capabilities, and the output voltage NHV after adjustment by the BOOST circuit is greater than the normal value. This reduces the bias voltage of the SPAD and reduces the PDE, affecting its sensitivity to the optical signal response. Furthermore, high speed and high current can cause ground voltage fluctuations at different locations on the printed circuit board (PCB) (also known as "ground bounce"), and even lead to overvoltage or undervoltage failures in some chips, affecting the normal operation of the circuit.

[0032] Figure 1B A schematic diagram showing another connection of a driving circuit for a single photon detector is shown. To improve the above-mentioned problem, this circuit achieves quenching by adding a large resistance R2 in series to the HV high voltage inside the SPAD, or alternatively, adding a large resistance R3 outside the SPAD. However, this way, although it can speed up the quenching of the SPAD, it will increase the time required for the SPAD to recover from quenching to respond to the optical signal, affecting the subsequent measurement of the optical signal by the lidar, affecting the ranging performance of the lidar.

[0033] The present disclosure proposes a driving circuit for a single photon detector. The driving circuit includes a regulating circuit and a ramping circuit. The regulating circuit is configured to receive an input voltage and output a first voltage. The ramping circuit is electrically coupled with the regulating circuit and electrically coupled with a first terminal of the single photon detector. The ramping circuit is configured to receive the first voltage and provide a second voltage at the first terminal of the single photon detector. The ramping circuit has an impedance to a high frequency signal that is greater than an impedance to a low frequency signal, and is configured to cause a duration in which a current in the single photon detector is greater than a first current threshold to be less than or equal to a first time threshold. Since the ramping circuit has an impedance to a high frequency signal that is greater than an impedance to a low frequency signal, when the single photon detector generates a current in response to an optical signal, the ramping circuit has difficulty maintaining the voltage magnitude of the second voltage using the first voltage output by the regulating circuit, which can cause the voltage difference across the single photon detector to decrease rapidly, achieving rapid quenching of the single photon detector. This will significantly reduce the duration of the large current generated by the single photon detector in response to the optical signal, reduce the time required for the single photon detector to recover the bias voltage after quenching, and alleviate the effects of the kick phenomenon, helping to improve the detection performance of the lidar.

[0034] Figure 2 A block diagram of a driving circuit 200 for a single photon detector of a first exemplary embodiment consistent with some embodiments of the present disclosure is shown. The driving circuit 200 can include a regulating circuit 202 and a ramping circuit 204, which is electrically coupled with the regulating circuit 202. The regulating circuit 202 can be used to receive an input voltage and regulate the input voltage to output a first voltage. The ramping circuit 204 can be used to receive the first voltage and provide a second voltage at a first terminal of the SPAD. Since the ramping circuit 204 has an impedance to a high frequency signal that is greater than an impedance to a low frequency signal, the ramping circuit has a delay effect on the change of the current.

[0035] In some embodiments, the ramping-down circuit 204 can be configured to cause the duration that the current through the single-photon detector is greater than the first current threshold to be less than or equal to a first time threshold. The first time threshold can be set in a range less than or equal to 10 ns, such as 1 ns, 2 ns, 3 ns, 4 ns, 5 ns, 6 ns, 7 ns, 8 ns, 9 ns, or 10 ns. For example, when the first time threshold is set to 5 ns, the current through the SPAD greater than the first current threshold can drop below the first current threshold within 5 ns; when the first time threshold is set to 2 ns, the current through the SPAD greater than the first current threshold can drop below the first current threshold within 2 ns, achieving accelerated quenching of the SPAD. The first current threshold can be determined based on device parameters of the single-photon detector, among others.

[0036] As the large current through the SPAD is reduced faster, the impact of the ground bounce phenomenon on the normal operation of the circuit is mitigated. In addition, as the duration that the SPAD responds to the optical signal is reduced, the SPAD is accelerated to quench, reducing the impact of the excessive echo energy generated by the high reflectivity object on the ranging performance of the lidar.

[0037] Figure 3 A block diagram of a driving circuit 300 for a single-photon detector is shown, which is consistent with some embodiments of the present disclosure. For example, the driving circuit 300 can be the driving circuit 200 in Figure 2 The driving circuit 300 can include a conditioning circuit 302 and a ramping-down circuit 304, which is electrically coupled to the conditioning circuit 302. For example, the conditioning circuit 302 can be the conditioning circuit 202 in Figure 2 and the ramping-down circuit 304 can be the ramping-down circuit 204 in Figure 2 .

[0038] In some embodiments, the ramping-down circuit 304 can include an inductive component 306 and a first capacitive component 308. The inductive component 306 can be electrically coupled between the conditioning circuit 302 and the first terminal of the single-photon detector. For example, the inductive component 306 can include an inductor. For another example, the inductive component 306 can further include a resistor, which is connected in series with the inductor. The first capacitive component 308 can be electrically coupled to the first terminal of the single-photon detector. For example, the first capacitive component 308 can include a capacitor. For another example, the first capacitive component 308 can include a capacitor and a resistor connected in series. The number of the above-mentioned inductor, resistor, and capacitor can be one, two, or more, respectively, for example. In the case where the number of the above-mentioned inductor, resistor, and capacitor is two or more, they can be connected in parallel, in series, or in a mixed manner.

[0039] In some embodiments, the quality factor Q of the ramping circuit 304 can be set to be less than a second threshold to reduce or avoid the ramping circuit from resonating. The second threshold can fall in a range less than or equal to 0.707, for example, the second threshold can be any value less than or equal to 0.707. According to the relationship of the quality factor Q with respect to the elements in the circuit, the minimum value Rmin of the equivalent resistance of the ramping circuit 304 can be determined by the following expression:

[0040]

[0041] In some embodiments, the time constant of the ramping circuit 304 can be set to be less than a third threshold to cause the ramping circuit 304 to output a second voltage that changes faster to the SPAD to reduce the time for the SPAD to recover from quenching to responding to the light signal, and reduce the near range blind zone of the LiDAR. The third threshold can be determined according to the desired near range blind zone of the LiDAR, for example, the third threshold can be any value less than or equal to the time of flight corresponding to the near range blind zone of the LiDAR. Thus, the maximum value of the equivalent resistance of the ramping circuit 304 can be further set according to the RLC time constant formula and the third threshold.

[0042] In some embodiments, the equivalent capacitance value of the first capacitive component 308 can be set to be less than a fourth threshold to cause the first capacitive component 308 to provide less charge to the SPAD, and thus cause the SPAD to quench faster.

[0043] Figure 4 A block diagram of a driving circuit 400 for a single-photon detector is shown for a third exemplary embodiment consistent with some embodiments of the present disclosure. For example, the driving circuit 400 can be the driving circuit 200 in Figure 2 or the driving circuit 300 in Figure 3 The driving circuit 400 can include a conditioning circuit 402 and a ramping circuit 404, the ramping circuit 404 being electrically coupled to the conditioning circuit 402. For example, the conditioning circuit 402 can be the conditioning circuit 202 in Figure 2 or the conditioning circuit 302 in Figure 3 and the ramping circuit 404 can be the ramping circuit 204 in Figure 2 or the ramping circuit 304 in Figure 3 .

[0044] In some embodiments, the conditioning circuit 402 can have a single output port, and can be controlled to output a first voltage having an amplitude that meets the requirements of a scene to the ramping circuit 404 via the single output port.

[0045] In other embodiments, the driving circuit 400 can further include a selection circuit 406. In this case, the regulating circuit 402 can be electrically coupled with the ramping circuit 404 through the selection circuit 406. For example, the regulating circuit 402 can have multiple output ports, and can be controlled to output the first voltage with different amplitudes from each of the multiple output ports. Thereby, the first voltage output from each of the multiple output ports can be switched by the selection circuit 406 to output the first voltage with an amplitude that meets the scenario requirement to the ramping circuit 404.

[0046] Figure 5 A block diagram of a driving circuit 500 for a single-photon detector is shown for a fourth exemplary embodiment consistent with some embodiments of the present disclosure. For example, the driving circuit 500 can be the driving circuit 200 in Figure 2 , the driving circuit 300 in Figure 3 , or the driving circuit 400 in Figure 4 . The driving circuit 500 can include a regulating circuit 502 and a ramping circuit 504, which is electrically coupled with the regulating circuit 502. For example, the regulating circuit 502 can be the regulating circuit 202 in Figure 2 , the regulating circuit 302 in Figure 3 , or the regulating circuit 402 in Figure 4 , and the ramping circuit 504 can be the ramping circuit 204 in Figure 2 , the ramping circuit 304 in Figure 3 , or the ramping circuit 404 in Figure 4 .

[0047] In some embodiments, the regulating circuit 502 can include a voltage transformer 506 and a second capacitive component 508. The voltage transformer 506 can be used to receive an input voltage and regulate the input voltage to output a first voltage that meets a scenario requirement. The voltage transformer 506 can be electrically coupled between the input voltage and the ramping circuit 504. For example, the voltage transformer 506 can be a BOOST transformer, a BUCK-BOOST transformer, or a SEPIC transformer, etc. The second capacitive component 508 can be used to store energy or filter to maintain and smooth the first voltage output by the regulating circuit.

[0048] In some embodiments, the second capacitive component 508 can be electrically coupled to a node between the voltage transformer 506 and the ramping circuit 504, at which the first voltage can be output.

[0049] In some embodiments, the second capacitive component 508 can be integrated in the voltage transformer 506 in a similar manner as described above. For example, the second capacitive component 508 can include a capacitor, etc.

[0050] In some embodiments, the driving circuit can further include a readout circuit, which can be electrically coupled to the second end of the SPAD for extracting a signal from the second end for subsequent processing and analysis.

[0051] In some embodiments, the readout circuit can include an analog-to-digital conversion component, which can be used to convert the amplified signal into digitized data for further analysis and storage. For example, the analog-to-digital conversion component can include a successive approximation register (SAR) analog-to-digital converter (ADC), a sigma-delta ADC, or the like. In some embodiments, the readout circuit can further include an amplification component electrically coupled to the analog-to-digital conversion component. The amplification component can be used to amplify the extracted signal for easier processing and analysis of the signal. For example, the amplification component can include a high-gain, low-noise differential amplifier, a transimpedance amplifier, or the like.

[0052] In some embodiments, the readout circuit can further include a third capacitive component for filtering out direct current signals and for protecting the circuit from surge impact. The third capacitive component can be electrically coupled to the second end of the SPAD before the amplification component and the analog-to-digital conversion component. For example, the third capacitive component can include a capacitor.

[0053] Due to the presence of the third capacitive component, the extracted signal is filtered before being transmitted to the amplification component and the analog-to-digital conversion component, thereby eliminating the direct current component therein and ensuring the correctness of the signal transmission and the stability of the circuit operation. The filtered signal (e.g., the electrical signal generated by the SPAD in response to the optical signal) is transmitted to the amplification component and the analog-to-digital conversion component for subsequent processing and analysis. In addition, the third capacitive component can protect the components in the circuit by absorbing surge current.

[0054] Figure 6 A schematic diagram of a connection of a driving circuit for a single-photon detector of a first exemplary embodiment consistent with some embodiments of the present disclosure is shown. As shown, VIN is an input voltage, and the driving circuit utilizes VIN to provide a driving voltage at the first end of a SPAD.

[0055] The driving circuit includes a regulation circuit and a ramping circuit. The regulation circuit includes a BOOST converter and a capacitor CI. The ramping circuit includes a resistor Rl, an inductor LI, and a capacitor C2. The regulation circuit utilizes VIN to output a negative high voltage NHV (i.e., a first voltage) at a node. The ramping circuit utilizes the negative high voltage NHV to provide a driving voltage (i.e., a second voltage) to the SPAD at the first end of the SPAD electrically coupled to the capacitor C2. The second end of the SPAD is electrically coupled to a positive high voltage HV via a resistor R2.

[0056] For example, in the case that the detected object has a high reflectivity (e.g., a traffic sign), the SPAD will respond quickly to the light reflected back by the object (referred to as "high back echo" for short). When a large back echo current is generated in the SPAD in response to the high back echo, the charge will be preferentially extracted from the capacitor C2, causing the second voltage at the first end of the SPAD electrically coupled to the capacitor C2 to drop quickly, and thus the voltage difference between the two ends of the single-photon detector (i.e., the bias voltage of the SPAD) decreases quickly, and the PDE decreases. This causes a decrease in the response to the high back echo and a significant decrease in the peak value of the back echo current in response, so that the SPAD accelerates quenching, and the influence of the ground bounce phenomenon is reduced together with the parasitic capacitance present in the circuit.

[0057] In some embodiments, since the circuit composed of the resistor R1 and the inductor L1 has a large inductive reactance for high-speed signals such as back echoes, there is essentially no current flowing through the circuit to charge the capacitor C2 during the SPAD response to the back echo signal. Since the charge on the capacitor C2 cannot be replenished through the NHV, R1, L1 during the SPAD response, the voltage of the capacitor C2 drops quickly, which also greatly accelerates the quenching process of the SPAD.

[0058] Due to the accelerated quenching of the SPAD, the charge extracted from the capacitor C1 for each high back echo is also significantly reduced, i.e., the first voltage fluctuation caused by the high back echo is smaller. This allows the regulation speed of the voltage converter (e.g., a BOOST converter) to adapt to the fluctuation of the first voltage, and the first voltage can be adjusted back to the normal value in time, reducing the need for structural design and control algorithm of the voltage converter.

[0059] In some embodiments, the quality factor Q of the ramping circuit can be set to be less than a second threshold to reduce or avoid resonance of the ramping circuit. According to the relationship of the quality factor Q with respect to the elements in the circuit, the minimum value of the resistor R1 can be determined according to the second threshold. As an example, the resistor R1 can be set to 10Ω, the inductor L1 can be set to 68nH, and the capacitor C2 can be set to 2nF. This makes the quality factor Q of the ramping circuit approximately equal to 0.583 (less than 0.707), reducing the risk of resonance in the circuit.

[0060] After the end of the echo, the charge will be extracted from the capacitor C1, and charged to the capacitor C2 through the resistor R1 and the inductor L1. In some embodiments, the time constant of the ramping circuit can be set to be less than a third threshold value to reduce the time for the SPAD to recover from quenching to respond to the light signal, and to reduce the near range blind zone of the LiDAR. The third threshold value can be determined based on the requirement of the near range blind zone of the LiDAR, and thus the maximum value of the resistor R1 can be determined further according to the RLC time constant formula and the third threshold value. As an example, the resistor R1 can be set to be 10Ω, the inductor L1 can be set to be 68nH, and the capacitor C2 can be set to be 2nF. This makes the charging time controllable to be about 20ns based on the time constant of the ramping circuit, and thus objects 3 meters away from the high reflectivity object can be detected normally.

[0061] In some embodiments, the capacitor C2 can be set to be less than a fourth threshold value. This helps to provide less charge to the SPAD to accelerate the quenching of the SPAD, and thus to reduce the effect of the ground bounce phenomenon. As an example, the capacitor C2 can be set to be 2nF.

[0062] In some embodiments, in order to have a proper energy storage level to maintain and smooth the negative high voltage output by the voltage transformer, as an example, the capacitor C1 can be set to be 1uF.

[0063] It should be understood that the above embodiments are discussed with respect to the case that the NHV is a negative high voltage. However, the scope of the present disclosure is not limited thereto. Since the SPAD only needs to be guaranteed to have a sufficient bias voltage applied to respond to the light signal to generate the electrical signal, in the case that the NHV output by the regulating circuit is a positive voltage, the SPAD can only be guaranteed to have the HV greater than the second voltage provided at the first end of the SPAD and the voltage difference between the HV and the second voltage greater than or equal to a sufficient bias voltage to respond to the light signal.

[0064] It should be understood that the above embodiments are discussed with respect to the case that the second voltage is provided at the first end of the SPAD and the fixed HV voltage is provided at the second end of the SPAD. However, the scope of the present disclosure is not limited thereto. Since the SPAD only needs to be guaranteed to have a sufficient bias voltage applied to respond to the light signal to generate the electrical signal, in the case that the second end of the SPAD is reversely connected to the first end, the SPAD can only be guaranteed to have the HV less than the second voltage and the absolute value of the difference between the HV and the second voltage greater than or equal to a sufficient bias voltage to respond to the light signal.

[0065] Figure 7 A schematic diagram of connections of a driving circuit for a single-photon detector is shown in accordance with a second exemplary embodiment of some embodiments of the present disclosure. Figure 7 The components of Figure 6 Similarly, the difference is that,Figure 7 A readout circuit is also included. The readout circuit is electrically coupled to the second end of the SPAD detector (e.g., electrically coupled between the resistor R2 and the SPAD detector) for extracting a signal from the second end for subsequent processing and analysis.

[0066] In some embodiments, the readout circuit can include an analog-to-digital conversion component. In some embodiments, the readout circuit can also include an amplification component electrically coupled with the analog-to-digital conversion component. As the amplification component amplifies the extracted signal, easier processing and analysis of the signal is achieved.

[0067] In some embodiments, the readout circuit can include a third capacitive component for filtering out direct current signals and for protecting the circuit from surge impact.

[0068] In addition to the readout circuit, Figure 7 The other components in Figure 6 are similar to the components in

[0069] Figure 8 A schematic diagram of a receiver 800 for a lidar consistent with some embodiments of the present disclosure is shown. As shown, the receiver 800 can include one or more single-photon detectors 802 and a drive circuit 804. The drive circuit 804 can be any of the drive circuits 200, 300, 400, 500 described above, for example. In some embodiments, the one or more single-photon detectors 602 can include a photoactive element and a quenching element. The photoactive element can be configured to generate an electrical signal in response to a light signal when its bias voltage is greater than or equal to an avalanche breakdown voltage, and the quenching element can be configured to decrease the bias voltage of the photoactive element below the avalanche breakdown voltage after the photoactive element responds to the light signal. For example, the single-photon detector can be formed by connecting a plurality of photoactive elements connected in parallel with a quenching element in series. For another example, the single-photon detector can be formed by connecting a plurality of photoactive elements each connected in series with a quenching element in parallel.

[0070] According to another exemplary embodiment of the present disclosure, a lidar is also provided.

[0071] Figure 9 A schematic diagram of a lidar 900 consistent with some embodiments of the present disclosure is shown. The lidar 900 can include a receiver 800 as described above.

[0072] The driving circuit for single photon detector, the receiver for lidar, and the lidar according to the exemplary embodiments of the present disclosure are described above. The driving circuit for single photon detector quickly reduces the current through the SPAD by the included ramping circuit, so that the SPAD accelerates quenching, which, together with the parasitic capacitance existing in the circuit, reduces the influence of the ground bounce phenomenon; by properly setting the parameters of each element in the ramping circuit, the quenching-recovery time of the SPAD is reduced, which reduces the influence on the ranging performance of the lidar, makes the timing on which the lidar operation depends more accurate, and improves the accuracy of the lidar measurement. And the above advantages make the adjustment circuit included in the driving circuit easier to operate, reduce the requirements of structural design and control algorithm, and reduce the complexity and cost of the system.

[0073] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The appearances of the phrase "in an embodiment" or "in embodiments" in various places throughout this specification are not necessarily all referring to the same embodiment, however. Furthermore, the particular features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0074] Furthermore, while some embodiments described herein include some features of other embodiments that are not included in all embodiments, combinations of features of different embodiments are intended to fall within the scope of the present disclosure and form different embodiments as would be understood by those skilled in the art. For example, in the appended claims, any of the claimed embodiments can be used in any combination.

[0075] It will be apparent to those skilled in the art that various modifications and variations can be made to the above-described exemplary embodiments of the present disclosure without departing from the spirit or scope of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of the present disclosure coming within the scope of the appended claims and their equivalents.

Claims

1. A drive circuit for a single photon detector, characterized by, comprising: a regulation circuit configured to receive an input voltage and output a first voltage; a ramping circuit electrically coupled with the regulation circuit and with a first terminal of a single-photon detector, the ramping circuit configured to receive the first voltage and provide a second voltage at the first terminal of the single-photon detector; wherein an impedance of the ramping circuit to a high-frequency signal is greater than an impedance to a low-frequency signal, and the ramping circuit is configured to cause a duration in which a current in the single-photon detector is greater than a first current threshold to be less than or equal to a first time threshold.

2. The drive circuit of claim 1, wherein, the ramping circuit comprises: an inductive component electrically coupled between the regulation circuit and the first terminal of the single-photon detector; a first capacitive component electrically coupled to the first terminal of the single-photon detector.

3. The drive circuit of claim 2, wherein, the first capacitive component comprises a capacitor.

4. The drive circuit of claim 2, wherein, the inductive component comprises a resistor and an inductor in series.

5. The drive circuit of claim 2, wherein, a quality factor of the ramping circuit is less than a second threshold.

6. The drive circuit of claim 2, wherein, a time constant of the ramping circuit is less than a third threshold.

7. The drive circuit of any one of claims 5-6, wherein, an equivalent capacitance value of the first capacitive component is less than a fourth threshold.

8. The drive circuit of claim 1, wherein, the regulation circuit comprises: a voltage transformer electrically coupled between the input voltage and the ramping circuit; and a second capacitive component electrically coupled to a node between the voltage transformer and the ramping circuit, wherein the regulation circuit is configured to output the first voltage at the node.

9. The drive circuit of claim 8, wherein, the voltage transformer comprises a BOOST converter.

10. The drive circuit of claim 1, wherein, the drive circuit further comprises a readout circuit electrically coupled to a second terminal of the single-photon detector.

11. A receiver for a lidar, comprising: comprising: one or more single-photon detectors; and a drive circuit as claimed in any of claims 1-10.

12. The receiver of claim 11, wherein, the single-photon detector comprises a photoactive element and a quenching element.

13. A lidar, comprising: comprising a receiver as claimed in claim 11 or 12.

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