State switching circuit, photoelectric detection array and optical detection system

Abstract

The present application provides a state switching circuit, a photoelectric detection array, and an optical detection system. The state switching circuit includes: a resistive voltage dividing circuit that leads out a first output terminal from at least one voltage dividing point among the resistors in the line between the voltage supply terminal and the ground terminal; the resistive voltage dividing circuit includes at least one first controllable switch located in the line, which is used to be in a corresponding switch state according to the received external control signal and the applied voltage, so as to form a voltage dividing signal at the first output terminal; a second controllable switch of the voltage output circuit is coupled to the first output terminal, and is used to be in a corresponding switch state according to the voltage supplied by the power supply terminal and the voltage dividing signal, so as to control the output of the second output terminal, and output a state switching signal to the photodetector coupled to the second output terminal to control the working state of the photodetector. The solution of the present application can reduce the static power consumption, and can cooperate with the optimization solution to simplify the circuit structure and optimize the circuit area and power consumption.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of optical detection devices, and in particular, to a state switching circuit, a photoelectric detection array, and an optical detection system. Background Technique

[0002] LiDAR is a sensor that uses lasers to achieve precise ranging. LiDAR emits laser pulses, and these pulses are reflected back when they encounter surrounding objects. By measuring the time it takes for the laser to reach each object and return, the precise distance to the object can be calculated. LiDAR emits multiple pulses per second, and by collecting these distance measurements and monitoring the azimuth of pulse transmission and reception, a three-dimensional environmental model, i.e., a point cloud, can be constructed.

[0003] LiDAR has a wide range of applications, including: autonomous driving (autonomous taxis, buses, trucks, logistics carts, etc.), mapping, smart cities / V2X, robotics, and security.

[0004] A single-photon avalanche diode (SPAD) is an avalanche photodiode (APD) that operates in a special state (Geiger mode) and can perform single-photon detection. When a certain reverse bias voltage Vbias (the voltage difference between the anode and cathode) is applied to the avalanche photodiode, photons carrying energy enter the P-N junction and transfer their energy to electrons in the covalent bond, causing the electrons to break free from the covalent bond to form electron-hole pairs, also known as photo-generated carriers (when an SPAD absorbs a photon to generate an electron-hole pair, it is called an initial electron-hole pair).

[0005] If the reverse bias voltage Vbias is large enough, the photo-generated carriers in the depletion layer can obtain high enough kinetic energy to break the covalent bond and generate electron-hole pairs when colliding with the lattice, and this process is also called impact ionization. New carriers will continuously generate new impact ionization, forming a chain effect, resulting in an avalanche multiplication effect of carriers, obtaining a very large pulse current. The lowest reverse bias voltage that can cause such an avalanche effect in the SPAD is called the avalanche breakdown voltage Vbreak, and the avalanche breakdown voltage is determined by the material and process of the SPAD. The actually applied reverse bias voltage Vbias will be appropriately greater than the avalanche breakdown voltage Vbreak.

[0006] As a photodetector, SPAD has the advantages of small size, high gain (single-photon detection), high sensitivity, and high dynamic range. Therefore, its demand in applications such as light intensity detection and laser ranging is also increasing. In practical applications, multiple SPADs can be connected to form a SPAD(s) array. A quenching circuit (to make the reverse bias voltage Vbias of the SPAD < the avalanche breakdown voltage Vbreak) and a recovery circuit (also known as a reset circuit, to make the reverse bias voltage Vbias of the SPAD > the avalanche breakdown voltage Vbreak) are added independently to each SPAD for use.

[0007] During the use of the SPAD array, due to the limitation of circuit system resources, it is often impossible to process the output information of all SPADs simultaneously. Therefore, the system generally processes the output of the SPAD array in a scanning form, that is, only processes the information of some SPADs at a moment, and then realizes the processing of the entire SPAD array through time-sharing multiplexing of system resources. The unselected SPADs in the array will also be triggered by noise light (which may also include signal light) and consume a large amount of unnecessary power.

[0008] Therefore, it is very necessary to turn off the unselected SPADs in the array to save the power consumption of the circuit, so a voltage switching circuit is needed to switch the voltage supply to the SPAD. However, the current voltage switching circuit has problems such as high power consumption, large area, limited voltage range, and complex circuit process and structure. Summary of the Invention

[0009] In view of this, a state switching circuit, a photodetector array, and an optical detection system are provided in the embodiments of the present application.

[0010] The embodiments of the present application provide a state switching circuit for a photodetector, including:

[0011] A resistive voltage dividing circuit that leads out a first output terminal from at least one voltage dividing point between the resistors in the line between the voltage supply terminal and the ground terminal;

[0012] The resistive voltage dividing circuit includes at least one first controllable switch located in the line, which is used to be in a corresponding switch state according to the received external control signal and the access voltage, so as to form a voltage dividing signal at the first output terminal;

[0013] A voltage output circuit, including: a power supply terminal, a second controllable switch, and a second output terminal;

[0014] The power supply terminal is coupled to the second controllable switch;

[0015] The second controllable switch is coupled to the first output terminal, and is used to be in a corresponding switch state according to the voltage supplied by the power supply terminal and the voltage dividing signal, so as to control the output of the second output terminal;

[0016] The second output terminal leads out the output terminal of the state switching circuit for coupling to at least one photodetector to output a state switching signal for the photodetector.

[0017] Optionally, the first controllable switch is configured at a predetermined position in the circuit relative to the voltage supply terminal so that the obtained access voltage and the external control signal cause the first controllable switch to be in a predetermined type of conduction state when conducting, and the type of the conduction state is related to the magnitude of the current in the circuit.

[0018] Optionally, the first controllable switch is an N-type metal-semiconductor transistor, whose drain is coupled to one end of a first resistor, and the other end of the first resistor is coupled to the voltage supply terminal; the source of the first controllable switch is coupled to one end of a second resistor, and the other end of the second resistor is coupled to the ground terminal; the gate of the first controllable switch is for receiving the external control signal, and the first controllable switch operates in the saturation region after conduction.

[0019] Optionally, the first controllable switch is an N-type metal-semiconductor transistor, whose drain is coupled to one end of a first resistor, and the other end of the first resistor is coupled to the voltage supply terminal; the source of the first controllable switch is coupled to one end of a second resistor, and the other end of the second resistor is coupled to the ground terminal; the gate of the first controllable switch is for receiving the external control signal.

[0020] Optionally, the resistive voltage dividing circuit includes: a plurality of selectable paths connected between the first output terminal and the ground terminal, and each selectable path includes a series-connected first controllable switch and a resistor.

[0021] Optionally, the resistive voltage dividing circuit includes: a plurality of voltage dividing points, wherein one or more selectable paths are formed between at least some of the voltage dividing points and the ground terminal, and each selectable path includes a first controllable switch.

[0022] Optionally, the second controllable switch is a P-type metal-semiconductor transistor, whose gate is coupled to the first output terminal, whose source is coupled to the power supply terminal, and whose drain leads out the second output terminal.

[0023] Optionally, when the first controllable switch is cut off, the generated voltage dividing signal causes the second controllable switch to be cut off, so as to turn off the photodetector for the output state switching signal.

[0024] Optionally, the first controllable switch and the second controllable switch are laterally diffused metal oxide semiconductor transistors.

[0025] Optionally, the resistive voltage dividing circuit is configured such that the output voltage dividing signal can cause the second controllable switch to operate in the linear region after conduction.

[0026] Optionally, the voltage output circuit further includes: a third controllable switch and a resistor coupled between the second output terminal and the ground terminal; the third controllable switch is configured to be in a corresponding switch state according to an external control signal to adjust the state switching signal.

[0027] Optionally, the photodetector includes: a resistor and a photodetection element connected in series between the second output terminal and the ground terminal in sequence, and the photodetection element includes: a single-photon avalanche photodiode.

[0028] An embodiment of the present application provides a photodetector array, including:

[0029] Multiple rows and multiple columns; wherein, multiple photodetector units are respectively provided in each row and each column, and each photodetector unit includes at least one photodetector;

[0030] A peripheral circuit, including: multiple state switching circuits as described above, and an output terminal of each state switching circuit is coupled to one or more photodetectors, a row of photodetector units or a column of photodetector units in a photodetector unit to output a state switching signal.

[0031] An embodiment of the present application provides an optical detection system, including:

[0032] An optical emission module, including: an optical emission array, including multiple rows and multiple columns; wherein, multiple optical emission units are respectively provided in each row and each column, and each optical emission unit includes at least one optical emitter; the optical emission array further includes an optical emission array driving circuit coupled to each optical emitter for emitting a detection laser beam;

[0033] An optical detection module, including: the photodetector array as described above for receiving a detection echo;

[0034] A control module, coupled to the optical emission array and the photodetector array; wherein, the control module is configured to generate a control signal to a first controllable switch of each state switching circuit in the photodetector array to control the state of a corresponding photodetector, so that the optical emission module and the optical detection module cooperate correspondingly to detect distance information of an external obstacle.

[0035] Optionally, a quantity ratio of the optical emission module to the optical detection module is x:1, where x≥2 and x is an integer.

[0036] Compared with the prior art, the technical solution of the embodiment of the present application has the following beneficial effects:

[0037] On the one hand, a solution of using a resistor voltage division circuit in cooperation with a voltage output circuit is adopted. By controlling the first controllable switch to form a voltage division signal output, the voltage supply magnitude of the photodetector is controlled by controlling the second controllable switch, and accordingly, the working state of the photodetector is controlled. In a possible implementation, when the first controllable switch and the second controllable switch are in the cut-off state, a low level is applied to the photodetector, and the photodetector does not work. In this state, the entire circuit can achieve no static power consumption, greatly reducing the power consumption.

[0038] On the other hand, the overall circuit structure in the solution of the embodiment of the present application is simple. Compared with the solutions in the prior art, it can effectively reduce the volume of the entire circuit, optimize the circuit area and power consumption. Moreover, it can also improve the fill factor of the entire photodetector.

[0039] On yet another hand, the voltage value of the voltage division signal can be adjusted by changing the structure of the resistor voltage division circuit, so as to control the working parameters of the photodetector, realizing adjustable working states of the flexible photodetector. In addition, the current in the circuit of the resistor voltage division circuit can also be adjusted to reduce the power consumption. Description of the Drawings

[0040] Figure 1 Schematic diagram of the structure of the photodetector implemented by the SPAD in the example.

[0041] Figure 2 Schematic diagram of the structure of the voltage switching circuit implemented by the voltage stabilizing circuit in the example.

[0042] Figure 3 Schematic diagram of the structure of the voltage switching circuit implemented by the level conversion circuit in yet another example.

[0043] Figure 4a Circuit function module diagram of the state switching circuit in the embodiment of the present application.

[0044] Figure 4b Schematic diagram of the structure of the state switching circuit in an embodiment of the present application.

[0045] Figure 4c Shown as Figure 4b Schematic diagram of the structure of the state switching circuit coupled to the photodetector in

[0046] Figure 4d Shown as Figure 4c Schematic diagram of the structure of the changed state switching circuit in

[0047] Figure 5 Schematic diagram of the simulation result of the switching effect of the state switching circuit in the embodiment of the present application.

[0048] Figure 6Shown is a schematic structural diagram of a state switching circuit in a variant embodiment of the present application.

[0049] Figure 7 Shown is a schematic structural diagram of a state switching circuit in another variant embodiment of the present application.

[0050] Figure 8 Shown is a schematic structural diagram of a state switching circuit in yet another variant embodiment of the present application.

[0051] Figure 9 Shown is a schematic structural diagram of a photodetector array in an embodiment of the present application.

[0052] Figure 10A Shown is a schematic structural diagram of the connection relationship between a state switching circuit and a photodetector in an embodiment of the present application.

[0053] Figure 10B Shown is a schematic structural diagram of the connection relationship between a state switching circuit and a photodetector in yet another embodiment of the present application.

[0054] Figure 10C Shown is a schematic structural diagram of the connection relationship between a state switching circuit and a photodetector in still another embodiment of the present application.

[0055] Figure 11 Shown is a schematic structural diagram of an optical detection system in an embodiment of the present application.

[0056] Figure 12 Shown is a schematic diagram of the controlled grouped cooperation between a light emission array and a photodetector array in an optical detection system in an embodiment of the present application. Detailed implementation manners

[0057] As mentioned above, a single-photon avalanche diode (SPAD) is a photodetector that is widely used in fields such as light intensity detection and laser ranging. As Figure 1 shown, a schematic circuit structure diagram of a photodetector implemented by a SPAD in an example is presented. It should be noted that this circuit structure is only a simple illustration and does not limit the circuit structure of the SPAD to be implemented strictly in accordance with this Figure 1 example. In actual scenarios, it may be implemented in combination with quenching circuits, recovery circuits, etc., and is not limited to the illustration.

[0058] From Figure 1It can be seen that the power supply terminal at the top is connected to the high-voltage power supply HV. One end of the resistor Rq is coupled to the power supply terminal, and the other end of Rq is coupled to the anode of the SPAD. The cathode of the SPAD is coupled to the ground terminal VSS. When the SPAD is selected, the HV is connected. The HV is higher than the breakdown voltage Vbreak of the SPAD, and the SPAD starts to work, that is, it detects the optical signal and converts it into an electrical signal. To make the SPAD in a non-working state, the HV is switched to a voltage lower than the breakdown voltage of the SPAD; if it is necessary for the SPAD to return to the working state, then switch back to the HV. In a possible example, the breakdown voltage Vbreak of the SPAD is between 20V and 40V, and the HV can be a high-voltage power supply of, for example, 40V. The high voltage here can be defined as more than 5V.

[0059] It can be seen that by switching the high and low levels applied to the anode of the SPAD, the working state of the SPAD can be controlled. Therefore, the above requirements can be achieved by implanting a voltage switching circuit. The following gives examples of various implementation methods through multiple examples.

[0060] As Figure 2 shown, a schematic structural diagram of implementing a voltage switching circuit through a voltage stabilizing circuit in an example is shown.

[0061] In this example, the gates of two P-type metal-semiconductor transistors PM1 and PM2 are connected together and connected to the drain of PM1. The PMOS conducts when the gate-source voltage Vsg is greater than the threshold voltage Vth of the transistor itself. The sources of PM1 and PM2 are connected to the high voltage HV, and the gates of PM1 and PM2 are connected to the upper end of R1; the sources of PM1 and PM2 are connected to HV. The drain of PM1 is connected to the drain of the N-type metal-semiconductor transistor NM1 through R1. The source of NM1 is connected to the ground terminal VSS, and the gate of NM1 is connected to the output terminal of the operational amplifier (AMP). The negative input terminal (i.e., the - terminal) of the AMP is connected to the reference voltage Vref, and the positive input terminal (i.e., the + terminal) is for inputting the high level Vhigh or the low level Vlow to be compared; the drain of PM2 is connected to the ground terminal VSS through the resistors R2 and R3, and the drain of PM2 also leads out the output terminal OUT_H to connect to the Figure 1 photodetector in

[0062] Let V+ represent the voltage at the + terminal. In some examples, V+ can be either Vhigh or Vlow and can be controlled externally, for example, applied by the control module of the lidar.

[0063] Specifically, when the SPAD is to be turned off, set V+ to Vlow to form Vref = Vlow, causing Vout_h to switch to the low level. At this time, Vout_h = Vlow * (R2 + R3) / R3; or, when the SPAD is to be started, set V+ to Vhigh, which can switch the high-voltage output Vout_h to the high level. At this time, Vout_h = Vhigh * (R2 + R3) / R3.

[0064] Figure 1 There will be certain problems in the circuit scheme in: 1) Whether Vout_h is a high voltage or a low voltage, there will be power consumption on AMP, PM1, PM2, and NM1. Specifically, there is not only dynamic power consumption during the high-low switching process of Vout_h; and because this circuit is a voltage regulation circuit converted for voltage switching, the principle of the voltage regulation circuit itself is not simply a "switch". Even when switched to different states (even when Vout_h outputs a low voltage state), the entire circuit still needs to work to perform "voltage regulation", so there is always static power consumption. 2) Due to the need for an operational amplifier, the area it occupies is relatively large, resulting in an increase in the area of the entire voltage switching circuit, which is not conducive to reducing the area of the integrated circuit and will reduce the fill factor of the photodetector.

[0065] Another example is Figure 3 which shows a schematic diagram of the circuit structure for implementing a voltage switching circuit in another example.

[0066] In Figure 3 what is shown is a voltage switching circuit implemented through a level conversion circuit. When used for high-low voltage switching of the SPAD, VDDH in the figure is a high voltage higher than the breakdown voltage of the SPAD, and VSSH can be a voltage slightly lower than the breakdown voltage. VDDL and VSSL are the low-voltage power supply and ground respectively. M 1 ~M 8 are MOS devices. To ensure the reliability of device operation and avoid crosstalk, Figure 2 in the scheme, M 3 ~M 8 and the output inverter I 2 all need to be placed in a high-voltage-resistant deep well (DEEP N-WELL, DNW).

[0067] The input IN_L comes from external control. For example, when applied to lidar, it is applied by the control module of the lidar.

[0068] Specifically, when the input IN_L is at a low level, the output OUT_H = the voltage value of VSSH, which is less than the breakdown voltage of the SPAD, turning off the connected SPAD; when the input IN_L is at a high level, the output OUT_H = the voltage value of VDDH, which is greater than the breakdown voltage of the SPAD, starting the connected SPAD to work.

[0069] Adopt Figure 3 In the circuit scheme, there are at least the following defects:

[0070] 1) A relatively large number of MOS devices are used in the entire circuit, and the circuit structure is relatively complex.

[0071] 2) The switching voltage range (VDDH-VSSH) of the high-voltage switching circuit will be restricted by the conventional MOS devices M 5 ~M 8 For example, M 5 ~M 8 are conventional 5V devices with a working voltage of 5V. Then Figure 3 the corresponding upper limit of the switching voltage is 5V. Exceeding this voltage value will cause reliability problems of M 5 ~M 8 Therefore, this voltage limitation of the level conversion circuit will ultimately result in too small a working voltage range of the SPAD, thus affecting the performance of the SPAD. Specifically, the photon detection efficiency (PDE) of the SPAD is related to the magnitude of the applied reverse bias voltage, and Figure 3 in the scheme of

[0072] Figure 3 Figure 3 In the scheme of the example, a deep well process (HV DNW) for isolating high voltage is required, that is, there is another layer of N- implantation under the NWELL, aiming to isolate the PWELL in the DNW from the p-substrate, making the substrate coupling noise smaller. However, the buried deep well process will affect the SPAD characteristics, and then lead to a conflict between the deep well process and the SPAD process. Therefore Figure 3 the scheme in the example has high process requirements for the device and cannot be applied to various types of SPADs.

[0073] In summary, in the above examples, a high-voltage switching circuit that can be used for a photodetector (such as a SPAD) is shown. However, some have problems of high power consumption and large area, and some have complex circuit structures, limited performance, and high device process requirements. It can be seen that it is difficult to find a voltage switching circuit for a photodetector that takes into account the advantages and gets rid of the defects.

[0074] In view of this, corresponding solutions are provided in the embodiments of the present application.

[0075] As Figure 4a shown, a schematic diagram of the circuit structure of the state switching circuit for a photodetector in the embodiments of the present application is shown.

[0076] The state switching circuit includes: a resistor voltage dividing circuit 41 and a voltage output circuit 42.

[0077] The resistor voltage dividing circuit 41 leads out a first output terminal 415 from at least one voltage dividing point between a resistor 413 in the line between a voltage supply terminal 411 and a ground terminal 412.

[0078] The resistor voltage dividing circuit 41 includes at least one first controllable switch 414 located in the line, which is used to be in a corresponding switch state according to a received external control signal and an access voltage, so as to form a voltage dividing signal at the first output terminal 415.

[0079] The voltage output circuit 42 includes: a power supply terminal 421, a second controllable switch 422 and a second output terminal 423. The power supply terminal 421 is coupled to the second controllable switch 422; the second controllable switch 422 is coupled to the first output terminal 415 and is used to be in a corresponding switch state according to the voltage supplied by the power supply terminal 421 and the voltage dividing signal, so as to control the output of the second output terminal 423.

[0080] The second output terminal 423 leads out the output terminal of the state switching circuit for being coupled to at least one photodetector 43 to output a state switching signal for the photodetector 43.

[0081] As Figure 4b shown, a circuit structure diagram showing the specific implementation of the state switching circuit in an embodiment of the present application is presented.

[0082] In Figure 4b the example, the voltage supply terminal is connected to HV, the ground terminal is connected to VSS, and the line is the line between HV and VSS. It should be noted that Figure 4b only HV is exemplarily used to supply power to the voltage supply terminal in this way, which is more convenient without introducing other voltage sources; however, in fact, the voltage of the voltage supply terminal is not limited to HV and may also be other voltages, as long as the functions of the entire circuit can be satisfied, and it is not limited to the illustration.

[0083] In Figure 4bIn the example, the first controllable switch can be exemplarily shown as an N-type metal-oxide-semiconductor transistor (MOS), i.e., NM1. Its drain (netA) is coupled to the other end of the second resistor R2, its source is grounded, and its gate EN is for introducing an external control signal to control its switching state. For example, when the Vgs of the NMOS transistor is greater than its threshold voltage Vth, that is, the external control signal through the EN terminal can control the conduction or cutoff of the first controllable switch. The relative magnitude value of Vgs and its threshold voltage Vth is related to the operating region of the MOS transistor, such as the linear region or the saturation region. If the first controllable switch operates in the linear region, when it is conducting, the value of the voltage-dividing signal VnetB is approximately HV*R2 / (R1 + R2).

[0084] In addition, in Figure 4b the example, it is exemplarily shown that the resistive voltage-dividing circuit includes two resistors: the first resistor R1 and the second resistor R2; one end of the first resistor is coupled to the voltage supply terminal, and the other end of the first resistor is coupled to one end of the second resistor to form a voltage-dividing point, which is led out as the first output terminal netB.

[0085] In Figure 4b the example, the second controllable switch PM1 in the voltage output circuit can also be implemented by a metal-oxide-semiconductor field-effect transistor. For example, a P-type metal-oxide-semiconductor field-effect transistor, i.e., PMOS. Its gate is coupled to the first output terminal, its source is coupled to the HV introduced by the power supply terminal, and its drain leads out the second output terminal OUT_H.

[0086] Optionally, the drain of the second controllable switch is also grounded through the resistor R3 and the third controllable switch NM2; in Figure 4b the example, NM2 is exemplarily shown as NMOS. Its gate ENb introduces an external control signal, its drain is coupled to one end of R3, and its source is coupled to VSS.

[0087] It should be noted that the external control signals are applied to the EN and ENb terminals to control the operation of the entire circuit to achieve the switching of high and low voltages at the output terminal OUT_H. In possible examples, the external control signal can come from a control module, such as the control module in a lidar. In the example of a mechanical lidar, the control module can be implemented by the control circuit in the upper bin plate of the mechanical lidar, such as the control module and its related circuits; or, in the example of a solid-state lidar, the control module can be implemented by the control module and its related circuits on the circuit board of the solid-state lidar. Among them, the solid-state lidar is a concept relative to the mechanical lidar. It can miniaturize, electronicize or replace the rotating mechanical structure. Therefore, relative to the rotational movement of the mechanical lidar, it is in a relatively fixed state. Taking the lidar solution that replaces the rotating mechanical structure as an example, reference can be made to the lidar based on a photoelectric detection array (such as a SPAD Array), etc.

[0088] For example Figure 4c , which shows a schematic diagram of the circuit structure after the output end of the state switching circuit is coupled to the photodetector. Figure 4c In the example, the photodetector is exemplarily shown as a box connected to the output terminal OUT_H, which can be based on Figure 1 The circuit shown is a SPAD and a resistor in series. However, the photodetector can also be implemented in other circuit structures, such as exchanging the position of the resistor and the SPAD itself, which is not shown here. In addition, the SPAD can also be used in conjunction with a quenching and recovery circuit, which is not shown one by one in the drawings.

[0089] according to Figure 4c Explain the control principle of the state switching circuit on the photodetector:

[0090] When the photodetector connected to the state switching circuit needs to be switched on, the output terminal OUT_H of the state switching circuit can be switched to a high voltage, and the specific process includes: the control signal EN is at a high level and ENb is at a low level. Then NM1 is turned on, while NM2 is turned off, and the line HV→R1→R2→NM1→VSS in the resistor divider circuit is turned on, and the current in the line is approximately I=HV / (R1+R2).

[0091] In some examples, in order to reduce this current I, the resistance values ​​of resistors R1 and R2 can be set larger. For example, when HV = 40V, if the current I is required to be 10uA, then R1 = 500K and R2 = 3500K can be selected. When I is small, NM1 can be made to work in the linear region (equivalent to a small resistor, much smaller than R1 and R2), that is, the voltage of the netA node is close to VSS. By resistor voltage division, the voltage of netB can be obtained = HV*R2 / (R1+R2). The netB voltage value is combined with a suitable PM1 (related to the Vth of PM1) to make PM1 work in the linear region (equivalent to a small resistor) and ensure the reliability of PM1. Furthermore, if PM1 is in the linear region, the voltage of the output terminal OUT_H can be made to be close to the HV value or the source input voltage value of the PM1 tube.

[0092] When the photodetector needs to be turned off to stop working, the output OUT_H of the state switching circuit can be switched to a low voltage, specifically: the external control signal EN is pulled low, ENb is pulled high, NM1 is turned off, and NM2 is turned on.

[0093] Since NM1 is cut off, the line of the resistor voltage divider circuit is blocked, so that netA is pulled up to the voltage value of HV, which can cut off PM1. The voltage of the output terminal OUT_H will be discharged to VSS by the NM2 and R3 branches.

[0094] existFigure 4b , 4c In the embodiment, NM2 and R3 are used to control the path for lowering the voltage of OUT_H. In actual implementation, those skilled in the art may also use other circuit module combinations to implement this function. Since the voltage lowering method of OUT_H is not limited to this method, NM2 and R3 are not necessary components.

[0095] like Figure 4d As shown, shown in Figure 4c The circuit structure diagram after removing R3 and NM2 is another embodiment of the state switching circuit in this application. Taking the implementation of the photodetector as SPAD as an example, since the output terminal OUT_H will be connected to the high voltage terminal (anode) of the SPAD, OUT_H can be reduced to below the breakdown voltage Vbreak by the operation of the SPAD itself, for example, after being quenched by the quenching circuit, the voltage is pulled down to stop the photodetector from working, and the purpose of shutting down the photodetector can also be achieved. Figure 4d The advantages of the example are that the circuit structure can be simplified to reduce the cost, and the external control signal can be simplified, that is, the external control signals of EN and ENb can be simplified to the external control signal requiring only EN.

[0096] In addition, it should be noted that the photodetection array of one row / one column shown here shares one state switching circuit. In other embodiments, each photodetector may correspond to one state switching circuit separately, so as to realize the selectability of each photodetector. Figure 4c In the example, the photodetectors are exemplarily shown to have multiple ones, that is, one state switching circuit can control the working states of the multiple photodetectors; but it should be noted that if it is a one-to-many method, then one state switching signal Vout_h can control multiple photodetectors to be in the same working state, such as being in a working state together, or a non-working state. Because in the application of the SPAD array, only some SPADs are selected to work, and these SPADs can share a high-voltage switching circuit; and most SPADs are not selected. In other words, only one (or a few) high-voltage switching circuits need to switch to high voltage, with static power consumption; and most other high-voltage switching circuits are switched to low voltage, without static power consumption. Therefore, the solution of this embodiment can ensure that the power consumed by the state switching circuit of the entire SPAD array is still small.

[0097] To achieve the control of each photodetector, in some examples, the state switching circuit and the connected photodetector can have a 1:1 relationship, that is, one state switching circuit controls the state of one photodetector. In some other examples, a gating device such as a multiplexer can also be provided between the output terminal OUT_H and the multiple photodetectors to control each photodetection element respectively.

[0098] In the above examples, the first controllable switch and the second controllable switch may be connected to high voltage. Therefore, in the case of being implemented by MOS transistors, a high-voltage-resistant type can be selected. For example, it can be implemented by a laterally-diffused metal-oxide semiconductor (LDMOS) transistor, which can meet the requirements in terms of high-voltage resistance and power control. Then, the first controllable switch can be an NLDMOS, and the second controllable switch can be a PLDMOS transistor; optionally, when there is the third controllable switch NM2, it can also be an NLDMOS transistor.

[0099] Of course, although the first controllable switch can be implemented as an NMOS and the second controllable switch can be implemented as a PMOS in the above Figures 4a to 4c examples, it can be understood that in other examples, the type of the MOS transistor can be changed, or other switching devices (such as bipolar transistors that may be applicable in certain scenarios) or switching circuits can be used for substitution, rather than being limited to the above examples.

[0100] For another example Figure 5 as shown, it shows the simulation timing result of simulating the state switching circuit in the embodiment of the present application.

[0101] It can be seen that as the external control signals EN and ENb change from 0 to a predetermined voltage a and b (such as 1.8V, not limited thereto), NM1 and NM2 are turned on, and the switching time of the waveform at the output terminal OUT_H from 0 to HV can be controlled within the microsecond level, such as about 1 microsecond in the figure, and the switching speed is very fast.

[0102] In the above examples, when the state switching circuit switches to output a low level, the first controllable switch NM1 is cut off, and the second controllable switch PM1 also follows its switching state and is cut off. Therefore, when the photodetector is not working, there is no static power consumption in the state switching circuit; thus, only when the state switching circuit outputs a high level, there is static power consumption in R1, R2, and NM1, and the static current is approximately I = HV / (R1 + R2), which is relatively small.

[0103] It can be seen that the static power consumption in the non-operating scenario can be greatly reduced through the state switching circuit. The reduction in this static power consumption is positively correlated with the number of photodetectors. In applications such as SPAD arrays, if there are multiple state switching circuits and the output terminal of each is coupled to the photodetectors of some of the SPADs, only the state switching circuit corresponding to the selected SPADs that are working will generate static power consumption, while the other state switching circuits maintain a low voltage output and have no static power consumption. This can greatly reduce the power consumption of the entire SPAD array. Compared with Figure 1 where there is static power consumption whether the SPAD is switched to the working or non-working state, there is a significant effect of reducing power consumption. It can be understood that when only a small part of the SPADs in the SPAD array are working, there is no static power consumption in the circuits of most SPADs. Compared with Figure 1 the power consumption reduction will be huge.

[0104] In addition, compared with Figure 2 the solution, which has defects such as a small voltage switching range, insufficient performance, high process requirements, and complex circuit, while the solution in the embodiment of the present application, through a resistor voltage division circuit in cooperation with a smaller number of controllable switches, the controllable switches can be implemented using high-voltage-tolerant MOS transistors, such as LDMOS. The circuit structure is simple and the devices can all tolerate high voltages without affecting the voltage switching range, ensuring performance; in addition, when using LDMOS to implement the controllable switches, etc., it can replace the deep well process such as Figure 2 the solution, and ensure the high practicality and reliability of the solution while greatly reducing the process requirements.

[0105] In some examples, when the photodetector is implemented using a SPAD, the breakdown voltage of the SPAD will be in a relatively wide range, and the breakdown voltage will change with temperature, which will make the HV value a variable quantity. According to the previous voltage division calculation formula, the voltage division signal of netB will change with HV. In this way, it is possible that the voltage amplitude of the voltage division signal exceeds the voltage range required for the second controllable switch to be in the expected switching state.

[0106] Therefore, in some examples, the embodiment of the present application can also provide some alternative solutions to actively adjust the voltage amplitude of the voltage division signal.

[0107] For example, Figure 6 shows a schematic circuit diagram of the state switching circuit in another embodiment of the present application.

[0108] In this example, the resistor voltage division circuit includes: multiple voltage division points formed by connecting between respective resistors. For example, Figure 6Resistors R1 to R6 are shown. The voltage division points formed by the resistor voltage division circuit include: the connection point netB between R1 and R6, the connection point netE between R6 and R5, the connection point netD between R5 and R4, and the connection point netC between R4 and R3. Among them, at least some of the voltage division points, such as netE, netD, and netC in the figure (any one or more of them) form one or more selectable paths to the ground terminal. For example, Figure 6 in this case, netE goes to VSS through NM5, netD goes to VSS through NM4, netC goes to VSS through NM3, and HV goes to VSS through each resistor R6, R5, R4, R2, the voltage division points formed by them, and NM1.

[0109] The first controllable switches NM3, NM4, and NM5 are similar to NM1 and can be implemented by NMOS (it can be implemented by NLDMOS). Their drains are coupled to the voltage division points connected to their respective selectable paths. Their sources are grounded, and their gates are EN4, EN3, and EN2 respectively, and can be controlled by an external control signal (that is, for example, the control circuit from the control module such as the upper deck of the lidar).

[0110] By controlling the selection of each branch of EN1 - EN4, the resistance value on the HV - resistor - Vss line can be adjusted, so as to obtain the optimal voltage of the netB node.

[0111] Specifically, when EN4 turns on NM5, R5, R4, and R2 are all bypassed, and R1 and R6 are used for voltage division, and VnetB = HV * R6 / (R1 + R6); when NM5 is off and EN3 turns on NM4, R4 and R2 are both bypassed, and R1 is used for voltage division with the series resistance of R6 and R5, and VnetB = HV * (R5 + R6) / (R1 + R5 + R6); when NM5 and NM4 are off and EN2 turns on NM3, R1 is used for voltage division with the series resistance of R6, R5, and R4, and VnetB = HV * (R4 + R5 + R6) / (R1 + R4 + R5 + R6); when NM5, NM4, and NM3 are off and NM1 is on, R1 is used for voltage division with the series resistance of R6, R5, R4, and R2, and VnetB = HV * (R2 + R4 + R5 + R6) / (R1 + R2 + R4 + R5 + R6).

[0112] It can be seen that Figure 6Four optional gears are exemplarily implemented herein. By pulling up one of the signals EN1 to EN4, the corresponding first controllable switch is turned on to adjust the voltage of netB. However, it should be noted that the illustrated embodiment in this figure is only an example. In actual implementation, the number of selectable paths, the number of resistors, the type of the first controllable switch, and the corresponding implemented gears, etc., can all vary according to actual requirements and are not limited to the above. Moreover, the display of R3 and NM2 on the right is also illustrative and not necessary.

[0113] In the case of implementing the controllable switch with MOS transistors, by designing the component configuration in the circuit, the controllable switch can be made to operate in the required on state, such as the linear region or the saturation region, and thus the effects of saving power consumption and area can also be achieved.

[0114] First, introduce the conditions for the MOS transistor to operate in the linear region and the saturation region. These conditions are related to its own threshold voltage Vth and the inter-pole voltage. For example, for an NMOS transistor, when Vgs > Vth and 0 < Vds < Vgs - Vth, the MOS transistor operates in the linear region; when Vgs > Vth and Vds > Vgs - Vth, the NMOS transistor operates in the saturation region. The PMOS transistor is the opposite, but the principle is similar. For example, when Vgs < Vth and 0 < Vds < Vth - Vgs, it operates in the linear region, and when Vgs < Vth and Vds > Vth - Vgs, it operates in the saturation region. By controlling the voltages of the gates g, drains d, and sources s of NM1, PM1, and NM2, the conduction characteristics can be controlled.

[0115] In some examples, based on Figures 4b to 4d the implementation, it can be known that if NM1 operates in the linear region, the current I in the resistor voltage division circuit will be approximately HV / (R1 + R2). If a smaller current is to be achieved, the resistance values of R1 and R2 need to be selected relatively large. By controlling NM1 to operate in the saturation region, a smaller current can be achieved by controlling its Vgs, which is beneficial to reducing the power consumption of the resistor voltage division circuit.

[0116] To satisfy Vgs > Vth and Vds > Vgs - Vth, there will be requirements for the Vth, gate voltage, drain voltage, and source voltage of the NM1 pair. When the source voltage is connected to VSS and fixed, the Vth, gate voltage, and drain voltage are mainly considered to enable NM1 to operate in the saturation region.

[0117] Thus, in some embodiments of the present application, by configuring the first controllable switch at a predetermined position in the circuit relative to the voltage supply terminal, the obtained access voltage can be made such that when the first controllable switch is turned on under the external control signal, it is in a predetermined type of conduction state (such as operating in the saturation region or the linear region), and the type of the conduction state is related to the magnitude of the current in the circuit. For example, the first controllable switch operates in the saturation region to form a relatively small current in the circuit to reduce power consumption.

[0118] That is to say, in the embodiments of the present application, the purpose of controlling a small current to reduce power consumption can be achieved by conveniently setting the position of the first controllable switch in the circuit. Moreover, compared with the method of increasing the resistance, it can reduce the occupation of the circuit area. In addition, since there is no need to change the amplitude of the access voltage (such as HV) and no new circuit elements need to be added, there will be no additional device and design costs.

[0119] For example, as Figure 7 shown, it shows a schematic circuit diagram of the state switching circuit in another embodiment of the present application.

[0120] Figure 7 Exemplarily, based on Figure 4b , the positions of the first controllable switch NM1 and the second resistor R2 are swapped. Compared with Figures 4b to 4d , when the resistors R1 and R2 in Figure 7 remain unchanged, the first controllable switch NM1 is configured at a position closer to HV, between R1 and R2. Specifically in terms of connection, the drain of NM1 is coupled to one end of the first resistor R1, the other end of R1 is coupled to the voltage supply terminal HV; the source of NM1 is coupled to one end of the second resistor R2, and the other end of R2 is coupled to the ground terminal VSS; the gate of NM1 is for receiving the external control signal EN. Compared with the embodiment of Figure 4b , Figure 7 in the embodiment of

[0121] a larger access voltage can be obtained at the drain of NM1 in the embodiment of 2 , which will be at HV when starting to conduct, so as to satisfy Vgs > Vth and Vds > Vgs - Vth, enabling NM1 to operate in the saturation region after conduction.

[0122] And in this case, the voltage of netB is HV - (Ven - Vth) * R1 / R2. By selecting appropriate resistance ratios of R1 and R2, it is also possible to satisfy the situation where PM1 operates in the linear region as in Figures 4b to 4d In the embodiment. Specifically, by reverse derivation, when PM1 operates in the linear region, assuming the threshold voltage of PM1 is 5V, the voltage of the voltage-dividing signal of netB is approximately (HV - 5V). Further, we get VnetB = (HV - 5V) = HV - (Ven - Vth) * R1 / R2. The ratio of R1 and R2 can be calculated to make PM1 operate in the linear region.

[0123] It should be noted that the above method of setting the ratio of R1 and R2 to make PM1 operate in the linear region is just an example. In other embodiments, PMOS transistors with different threshold voltages can also be selected to implement PM1.

[0124] Although it is described in the above example that PM1 operates in the linear region after conduction, it is only exemplary; in actual implementation, it is also possible to make PM1 operate in the saturation region by selecting PM1 with corresponding threshold voltages, controlling the voltage amplitude of the netB voltage-dividing signal, etc. When R3 is connected, the current I and the amplitude of the state switching signal Vout_h generated by R3 at the output terminal OUT_H can be controlled to satisfy the operation of the photodetector and the required PDE can also be achieved; or, when R3 is not connected to the output terminal OUT_H, the amplitude of the state switching signal Vout_h is approximately HV.

[0125] In the previous Figure 6 In the embodiment, it is shown that the voltage division output of netB is adjusted by the way of gating resistors in series; correspondingly, it can also be implemented by the way of gating resistors in parallel. For example, the resistor voltage division circuit may include: multiple selectable paths connected between the first output terminal and the ground terminal, and each selectable path includes a first controllable switch and a resistor connected in series.

[0126] Specifically, for example Figure 8 As shown, it shows the circuit structure diagram of the state switching circuit in another embodiment of the present application.

[0127] In Figure 8 In the example, it is exemplarily based on the Figure 7 embodiment. In the way of connecting the first controllable switch and then the resistor in series from netB to Vss, that is, the drains of several NMOS transistors NM5, NM4, NM3, and NM1 are coupled to netB, the sources of NM5, NM4, NM3, and NM1 are grounded through R5, R4, R3, and R2 respectively, and the gates of NM5, NM4, NM3, and NM1 are supplied with external control signals EN4, EN3, EN2, and EN1.

[0128] By turning on one or more of NM5, NM4, NM3, and NM1, the resistance in the selected strobable path can be separately voltage-divided with R1, or after being connected in parallel, voltage-divided with R1. For example, when NM5 and NM4 are turned on and NM1 and NM3 are turned off, the parallel resistance of R5 and R4 is voltage-divided with R1, and a voltage-divided signal for the output of netB is formed. Compared with the voltage division of a single resistor with R1, the resistance value decreases after the resistors are connected in parallel, and the voltage amplitude of the voltage-divided signal decreases when voltage-divided with R1.

[0129] Of course, in other embodiments, Figure 8 each strobable path in Figure 4b may also refer to the form where the resistor is on top and the first controllable switch is at the bottom in Figure 8 Therefore, it is not limited to the

[0130] It should be particularly noted that although NM1, NM3, NM4, NM5, etc. in Figure 6 and Figure 8 are all called the first controllable switches, they are so named only because of their same functional type, which does not mean that they are the same device.

[0131] Combined with the above state switching circuit and the photodetector it controls, further specific applications can also be implemented in the embodiments of the present application.

[0132] Such as Figure 9 shown, a schematic structural diagram of the photodetector array in the embodiments of the present application is presented.

[0133] The photodetector array 90 is shown in a two-dimensional form, including multiple rows and multiple columns. Among them, each row and each column are respectively provided with multiple photodetector units 91. Each photodetector unit 91 can serve as a pixel in the array. Each pixel may include at least one photodetector 911. For example, Figure 9 shown in Figure 9 each pixel contains 2×2 = 4 photodetectors 911. Each photodetector 911 can be implemented by a SPAD, thereby improving the dynamic range of detection. It should be noted that the number of photodetectors 911 in each pixel shown in the figure is only an example, and it can be changed in other instances, such as 1×1 = 1, 3×3 = 9, etc. It is not limited to

[0134] Figure 9The photoelectric detection array therein has a peripheral circuit 92, and the peripheral circuit 92 may include a plurality of state switching circuits 921 in the foregoing embodiments. The output end of each state switching circuit 921 is coupled to one or more photodetectors 911 in a photoelectric detection unit 91, a row of photoelectric detection units 91, or a column of photoelectric detection units 91 to output a state switching signal for control according to an external control signal. In addition, if the photodetector 911 is implemented by a SPAD, the peripheral circuit 92 may further include a quenching circuit and a reset circuit (not shown) for each SPAD, etc., which will not be elaborated in detail here.

[0135] In practical applications, for example Figure 10A As shown, each of the photodetectors 1001A, 1001B, 1001C, 1001D in the photoelectric detection unit 1000 of the photoelectric detection array may be coupled with a state switching circuit 1002A, 1002B, 1002C, 1002D. Among them, 1001A, 1001B, 1001C are selected and controlled by the state switching circuits 1002A, 1002B, 1002C to be in the working state to detect photons, which are presented as black circles in the figure; while 1002D makes 1001D in the non-working state, presented as a white circle. In this example, the photodetectors 1001A, 1001B, 1001C, 1001D can be independently turned on or off.

[0136] Alternatively, in other examples, the states of 1001A, 1001B, and 1001C can be controlled by one state switching circuit, while the state of 1001D is controlled by another state switching circuit. In this example, 1001A, 1001B, and 1001C can be turned on or off simultaneously, and 1001D is independently turned on or off relative to 1001A, 1001B, and 1001C.

[0137] It can be understood that by independently controlling the on or off of each photodetector in the photoelectric detection array, the control is made more precise, improving the detection accuracy.

[0138] For another example Figure 10B As shown, a row of photoelectric detection units in the photoelectric detection array can be controlled by one state switching circuit, shown as a row of photoelectric detection units corresponding to the A frame in the figure, and each photoelectric detection unit in A is controlled by a state switching circuit 1003 to be turned on or off simultaneously.

[0139] For yet another example Figure 10C As shown, a column of photoelectric detection units in the photoelectric detection array can be controlled by one state switching circuit, shown as a column of photoelectric detection units corresponding to the B frame in the figure, and each photoelectric detection unit in B is controlled by a state switching circuit 1004 to be turned on or off simultaneously.

[0140] By simultaneously turning on or off multiple photoelectric detection units, it is possible to solve the problems of increasing the dynamic range and reducing the area and power consumption of the photoelectric detection array.

[0141] In some examples, the photoelectric detection array can be applied to an optical detection system and is located in the receiving part for detecting optical signals. The optical detection system can be implemented in a solid-state lidar; solid-state lidar is relative to mechanical lidar. Among them, mechanical lidar means that there is a macroscopic rotation in its emission system and receiving system, that is, by continuously rotating the laser emission head, the faster and more accurate laser is changed from "line" to "plane" to achieve the purpose of dynamic scanning and dynamic information reception; while solid-state lidar cancels the rotating mechanical structure and uses an optical emission array and a corresponding photoelectric detection array for optical emission and echo reception.

[0142] Such as Figure 11 shown, which shows a schematic structural diagram of the optical detection system in an embodiment of the present application. The optical detection system 110 can be implemented in a lidar.

[0143] The optical detection system 110 includes: an optical emission module 111, an optical detection module 112, and a control module 113. Among them, the optical emission module 111 refers to the part in the optical detection system for laser emission (which can include circuits, devices, structures, etc.); the optical detection module 112 refers to the part in the optical detection system for detecting the echo signal of the laser (which can include circuits, devices, structures, etc.).

[0144] The optical emission module 111 includes an optical emission array 1111, which is implemented, for example, by a vertical-cavity surface-emitting laser (VCSEL) array. The optical emission array 1111 includes multiple rows and multiple columns. Among them, each row and each column are respectively provided with multiple optical emission units 11111, and each optical emission unit 11111 includes at least one optical emitter; the optical emission array 1111 is also correspondingly configured with an emission array driving circuit, which is coupled to each optical emitter for driving operation.

[0145] The optical detection module 112 includes: a photoelectric detection array 1121, and the photoelectric detection array 1121 can be implemented by, for example, Figure 9 、 Figures 10A to 10C any one of them to receive the optical echo signal after the detection laser beam reaches the obstacle. In addition, the optical detection module 112 can also include a signal readout circuit (not shown) for reading out the signal generated by the photoelectric detection array 1121 and transmitting it to the control module 113.

[0146] In the optical detection system, an emission lens group 1114 may also be provided on the light output path of the light emission array 1111; in the optical detection system, a receiving lens group 1122 may also be provided, and the photoelectric detection array 1121 may be located on the focal plane of the receiving lens group 1122.

[0147] The control module 113 is coupled to the light emission array 1111 and the photoelectric detection array 1121; wherein, the control module 113 is used to generate a control signal to the first controllable switch of each state switching circuit in the photoelectric detection array 1121 to control the state of the corresponding photodetector. For example, referring to Figures 3 to 8 In the embodiment, for example, applying Figure 3 In the state switching circuit of the embodiment, the control module 113 sends a control signal to control the output of OUT_H by EN1 of, for example, NM1, and also sends a control signal to ENb when NM2 is set to be used for switching the working or non-working state of the photodetector; or applying Figure 8 In the state switching circuit of the example, the control module 113 sends control signals to EN1, ENb, EN2, EN3, and EN4 to generate a required voltage dividing signal to control the output of OUT_H to control the photoelectric detection array 1121 to be in a corresponding state.

[0148] In the application scenario of the solid-state lidar, the control module 113 may be the control module in the solid-state lidar, for example, it may be implemented by a control chip on the circuit board of the solid-state lidar and its related circuits. The control module 113 can cooperate with each other by controlling the light emission array 1111 and the photoelectric detection array 1121 to detect the distance information of the external obstacle 114.

[0149] For example, the control module 113 sequentially sends a first control signal to the light emission module 111 to control the light emitters in one or more rows / columns in the light emission module 111 to emit laser light, and sends a second control signal to the light receiving module to select one or more rows / columns of photoelectric detection units (or one or more of the light detectors therein), so that the state switching circuit switches them to the working state to detect the echo signal after the laser reaches the obstacle.

[0150] As Figure 12 shown, a schematic diagram showing the grouped working mode of the optical detection system in the embodiment of the present application is presented.

[0151] This example is used to illustrate the process of respectively grouping corresponding parts of the light emission array 121 and the photoelectric detection array 122, and then sequentially cooperating according to the corresponding groups to perform light signal transmission and reception.

[0152] In the column - column grouping mode, assume that the first - column light emitter emits light at time t1, which is presented as circles with various twill patterns in T1 in the figure, and correspondingly, the photoelectric detection units of the first column are activated through the state - switching circuit in the embodiment of the present application, which are presented as circles with various cross - grain patterns in R1 in the figure, to receive the echo signal formed by the light emitted by the first - column light emitter after being reflected by the obstacle 123; and so on. At time t2, the second - column light emitter emits light, and correspondingly, the photoelectric detection units of the second column are activated through the state - switching circuit in the embodiment of the present application to receive the echo signal formed by the light emitted by the first - column light emitter after being reflected by the obstacle.

[0153] In other examples, it is also possible to group by rows, or group in an m×n sub - array to cooperate in the process of transmitting and receiving optical signals. The grouping method is not limited by Figure 12 the implementation manner.

[0154] In addition, in some optional examples, the number ratio of the optical - emission module to the optical - detection module is x:1, where x≥2 and x is an integer. That is, the number - corresponding relationship between the optical - emission module and the optical - detection module is many - to - one. When the light emitters in the optical - emission module are limited by their sizes, more light emitters are used to share the work of meeting the same power requirement, so as to achieve more stable and uniform light output.

[0155] Compared with the prior art, the technical solution of the embodiment of the present application has the following beneficial effects:

[0156] On the one hand, a scheme of a resistor voltage - dividing circuit cooperating with a voltage - output circuit is adopted. By controlling the first controllable switch to form a voltage - dividing signal output, the voltage - supply state of the photodetector is controlled by controlling the second controllable switch. In a possible implementation, when the first controllable switch and the second controllable switch are in the cut - off state, a low level is applied to the photodetector, and the photodetector does not work. In this state, the entire circuit can achieve no static power consumption, greatly reducing the power consumption.

[0157] On the other hand, the overall circuit structure in the embodiment of the present application is simple. Compared with the scheme in the prior art, it can effectively reduce the volume of the entire circuit, optimizing the circuit area and power consumption.

[0158] On the other hand, through the structural change of the resistor voltage - dividing circuit, the voltage value of the voltage - dividing signal can be adjusted, etc., so as to control the working parameters of the photodetector and realize flexible adjustment of the working state of the photodetector; in addition, the current in the circuit of the resistor voltage - dividing circuit can also be adjusted to reduce the power consumption.

[0159] In the description of this specification, the reference term "coupled" refers to the direct or indirect electrical connection between elements in a circuit.

[0160] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0161] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0162] Although the embodiments of the present application are disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present application. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A state switching circuit for a photodetector, characterized in that, it includes: A resistor voltage division circuit, including: A voltage supply terminal and a ground terminal, A plurality of resistors located between the voltage supply terminal and the ground terminal, wherein at least one voltage division point is included between the plurality of resistors, and a first output terminal is led out from the at least one voltage division point, and At least one first controllable switch located between the voltage supply terminal and the ground terminal, configured to be in a corresponding switch state according to the received external control signal and the access voltage, so as to form a voltage division signal at the first output terminal; and A voltage output circuit, including: A power supply terminal, A second controllable switch coupled to the power supply terminal and the first output terminal, configured to be in a corresponding switch state according to the voltage supplied by the power supply terminal and the voltage division signal, so as to control the output of the second output terminal, and The second output terminal leads out the output terminal of the state switching circuit, and the output terminal is used to be coupled to at least one photodetector and output a state switching signal for the photodetector.

2. The state switching circuit according to claim 1, characterized in that, The first controllable switch is configured at a predetermined position relative to the voltage supply terminal in the circuit of the resistor voltage division circuit, so that the obtained access voltage and the external control signal make the first controllable switch be in a predetermined type of conduction state when conducting, and the type of the conduction state is related to the magnitude of the current in the circuit.

3. The state switching circuit according to claim 1, characterized in that, The first controllable switch is an N-type metal-semiconductor transistor, whose drain is coupled to one end of a first resistor, and the other end of the first resistor is coupled to the voltage supply terminal; The source of the first controllable switch is coupled to one end of a second resistor, and the other end of the second resistor is coupled to the ground terminal; the gate of the first controllable switch is for receiving the external control signal, and the first controllable switch operates in the saturation region after conduction.

4. The state switching circuit according to claim 1, characterized in that, The first controllable switch is an N-type metal-semiconductor transistor, whose drain is coupled to one end of a first resistor, and the other end of the first resistor is coupled to the voltage supply terminal; The source of the first controllable switch is coupled to one end of a second resistor, and the other end of the second resistor is coupled to the ground terminal; the gate of the first controllable switch is for receiving the external control signal.

5. The state switching circuit according to claim 1, characterized in that, The resistor voltage division circuit includes: a plurality of selectable paths connected between the first output terminal and the ground terminal, and each selectable path includes a first controllable switch and a resistor connected in series.

6. The state switching circuit according to claim 1, characterized in that, The resistor voltage division circuit includes: a plurality of voltage division points, wherein one or more selectable paths are formed between at least some of the voltage division points and the ground terminal, and each selectable path includes a first controllable switch.

7. The state switching circuit according to claim 1, 3 or 4, characterized in that, The second controllable switch is a P-type metal-semiconductor transistor, whose gate is coupled to the first output terminal, whose source is coupled to the power supply terminal, and whose drain leads out the second output terminal.

8. The state switching circuit according to claim 7, wherein, when the first controllable switch is turned off, the generated voltage division signal turns off the second controllable switch, so that the output state switching signal turns off the photodetector.

9. The state switching circuit according to claim 7, wherein, the first controllable switch and the second controllable switch are lateral diffused metal oxide semiconductor transistors.

10. The state switching circuit according to claim 7, wherein, the resistor voltage division circuit is configured such that the output voltage division signal can turn on the second controllable switch and then operate in the linear region.

11. The state switching circuit according to claim 1, wherein, the voltage output circuit further includes: a third controllable switch and a resistor coupled between the second output terminal and the ground terminal; the third controllable switch is used to be in a corresponding switch state according to an external control signal to adjust the state switching signal.

12. The state switching circuit according to claim 1, wherein, the photodetector includes: a resistor and a photodetection element connected in series between the second output terminal and the ground terminal in sequence, and the photodetection element includes: a single photon avalanche photodiode.

13. A photodetection array, wherein, it includes: a plurality of rows and a plurality of columns; wherein, each row and each column are respectively provided with a plurality of photodetection units, and each photodetection unit includes at least one photodetector; a peripheral circuit, including: a plurality of state switching circuits according to any one of claims 1 to 12, and the output terminal of each state switching circuit is coupled to one or more photodetectors, a row of photodetection units or a column of photodetection units in a photodetection unit to output a state switching signal.

14. An optical detection system, wherein, it includes: a light emission module, including: a light emission array, including a plurality of rows and a plurality of columns; wherein, each row and each column are respectively provided with a plurality of light emission units, and each light emission unit includes at least one light emitter; the light emission array further includes a light emission array driving circuit coupled to each light emitter for emitting a detection laser beam; a light detection module, including: the photodetection array according to claim 13 for receiving a detection echo; a control module coupled to the light emission array and the photodetection array; wherein, the control module is used to generate a control signal to the first controllable switch of each state switching circuit in the photodetection array to control the state of the corresponding photodetector, so that the light emission module and the light detection module cooperate correspondingly to detect the distance information of an external obstacle.

15. The optical detection system according to claim 14, wherein, the quantity ratio of the light emission module to the light detection module is x:1, x≥2, and x is an integer.

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