Circuit for laser detection, laser radar and carrier

Abstract

The invention provides a circuit for laser detection, a laser radar and a carrier, and relates to the technical field of photoelectricity. The circuit for laser detection comprises a working circuit and a protection circuit connected in parallel with the working circuit. The working circuit comprises a first photodiode and is configured to detect echoes under working voltage, the protection circuit comprises a second photodiode, doped ions of the second photodiode and doped ions of the first photodiode are distributed in the longitudinal direction, and the break-over voltage of the protection circuit is larger than the working voltage. And the impedance of the switched-on protection circuit is smaller than that of the switched-on working circuit. According to the invention, the degree of damage to the working circuit caused by electrostatic discharge can be reduced.

Description

Technical Field

[0001] This disclosure relates to the field of optoelectronic technology, and more particularly to a circuit, lidar, and carrier for laser detection. Background Technology

[0002] LiDAR (Light Detection and Ranging) emits laser beams towards an object and receives the reflected laser beams (also known as echoes). LiDAR can then determine information about the object based on these echoes, such as its position, velocity, and attitude.

[0003] LiDAR systems can be damaged by electrostatic discharge (ESD) in practical applications. When ESD occurs, the lidar circuitry may experience voltages and instantaneous high currents significantly higher than the normal operating voltage. ESD can cause permanent damage to the circuitry or its components, rendering the lidar malfunction. Therefore, improving the ESD tolerance of lidar circuitry to reduce the extent of ESD damage is an important issue. Summary of the Invention

[0004] This disclosure provides a circuit for laser detection. By incorporating a protection circuit with a high on-state voltage and low on-state impedance, the extent of ESD damage to the operating circuit can be reduced.

[0005] In a first aspect, this disclosure provides a circuit for laser detection. The circuit for laser detection includes a working circuit and a protection circuit connected in parallel with the working circuit. The working circuit includes a first photodiode configured to detect echoes at a working voltage. The protection circuit includes a second photodiode with the same longitudinal distribution of doped ions as the first photodiode. The forward voltage of the protection circuit is greater than the working voltage, and the impedance of the protection circuit after it is turned on is less than the impedance of the working circuit after it is turned on.

[0006] Optionally, the second photodiode includes a plurality of photodiodes connected in series, wherein the plurality of photodiodes connected in series includes at least one reverse-biased photodiode.

[0007] Optionally, the plurality of photodiodes connected in series may include at least two reverse-biased photodiodes.

[0008] Optionally, the multiple photodiodes connected in series include one reverse-biased photodiode and multiple forward-biased photodiodes.

[0009] Optionally, the circuit for laser detection further includes a substrate; wherein the operating circuit and the protection circuit are formed on the substrate; and the area occupied by the second photodiode on the substrate is smaller than the area occupied by the first photodiode on the substrate.

[0010] Optionally, the protection circuit includes a first protection circuit and a second protection circuit connected in parallel with the first protection circuit. The first protection circuit includes a second photodiode, and the second protection circuit includes a third photodiode. The doped ions of the second and third photodiodes have the same vertical distribution. The impedance of the first protection circuit after it is turned on is less than the impedance of the working circuit after it is turned on, and the impedance of the second protection circuit after it is turned on is less than the impedance of the working circuit after it is turned on.

[0011] Optionally, the operating circuit also includes a quenching circuit. The quenching circuit is connected in series with the first photodiode and is configured to restore the bias voltage of the first photodiode after an avalanche effect occurs.

[0012] Optionally, the circuit for laser detection further includes a quenching circuit. The quenching circuit is configured to restore the bias voltage of the first photodiode after an avalanche effect occurs. A first terminal of the quenching circuit is connected to one end of the operating circuit and also to one end of the protection circuit.

[0013] Optionally, the quenching circuit includes a quenching resistor or a metal-oxide-semiconductor field-effect transistor (MOSFET).

[0014] Secondly, this disclosure provides a lidar. The lidar includes a laser and a laser detection circuit as described in any one of the first aspects. The laser is configured to emit laser light during operation, and the laser detection circuit is configured to receive the echo corresponding to the laser light during operation.

[0015] Thirdly, this disclosure provides a carrier. The carrier includes a connector and a lidar as described in the second aspect. The connector is used to connect the lidar and the carrier.

[0016] In this disclosure, a protection circuit with high on-voltage and low on-resistance can be incorporated into the circuit used for laser detection, thereby reducing the extent of ESD damage to the operating circuit. The doped ions of the first and second photodiodes have a consistent vertical distribution. This means that the second photodiode can be obtained with minimal or no additional process steps based on the fabrication steps of the first photodiode. In this way, the design and manufacturing costs of the circuit can be reduced or minimized. Attached Figure Description

[0017] Figure 1 An example diagram of a lidar consistent with some embodiments of this disclosure is shown.

[0018] Figure 2A structural example diagram of a circuit for laser detection, consistent with some embodiments of this disclosure, is shown.

[0019] Figure 3 A structural example diagram of a protection circuit consistent with some embodiments of this disclosure is shown.

[0020] Figure 4 A structural example diagram of a protection circuit consistent with some embodiments of this disclosure is shown.

[0021] Figure 5 A structural example diagram of a protection circuit consistent with some embodiments of this disclosure is shown.

[0022] Figure 6 A schematic diagram of a circuit structure consistent with some embodiments of this disclosure is shown.

[0023] Figure 7 A schematic diagram of a circuit structure consistent with some embodiments of this disclosure is shown.

[0024] Figure 8 A schematic diagram of a circuit structure consistent with some embodiments of this disclosure is shown.

[0025] Figure 9 A schematic diagram of a circuit structure consistent with some embodiments of this disclosure is shown.

[0026] Figure 10 A schematic diagram of a circuit structure consistent with some embodiments of this disclosure is shown.

[0027] Figure 11 A schematic diagram of a circuit structure consistent with some embodiments of this disclosure is shown.

[0028] Figure 12 A schematic diagram of a circuit structure consistent with some embodiments of this disclosure is shown.

[0029] Figure 13 A structural example diagram of a vehicle consistent with some embodiments of this disclosure is shown. Detailed Implementation

[0030] Figure 1 An example diagram of a lidar system consistent with some embodiments of this disclosure is shown. Please refer to... Figure 1The lidar 10 includes a laser 100 and circuitry 200 for laser detection (hereinafter referred to as circuitry 200). The laser 100 is configured to emit laser light during operation. The laser 100 may include one or more types of lasers. For example, the laser 100 may include a vertical cavity surface emitting laser (VCSEL), a photonic crystal surface emitting semiconductor laser (PCSEL), or an edge emitting laser (EEL). A portion of the laser light emitted by the lidar towards an object is reflected back by the object, forming an echo. The circuitry 200 is configured to receive the echo during operation. In some embodiments, the circuitry 200 may be a circuit integrated using semiconductor technology. In some embodiments, the circuitry 200 may also be located within a chip in the lidar 10 used to receive the echo.

[0031] Figure 2 A structural example diagram of a circuit for laser detection, consistent with some embodiments of this disclosure, is shown. Please refer to... Figure 2 Circuit 200 may include a working circuit 210 and a protection circuit 230 connected in parallel with the working circuit 210. The working circuit 210 includes a first photodiode 211. The working circuit is configured to detect echoes at an operating voltage. The first photodiode 211 may include an avalanche photodiode (APD), a single-photon avalanche photodiode (SPAD), or a silicon photomultiplier (SiPM), etc.

[0032] In some embodiments, the operating circuit 210 includes a plurality of first photodiodes 211 connected in parallel. For example, the operating circuit 210 may include three first photodiodes 211 connected in parallel. The plurality of first photodiodes 211 may operate simultaneously or selectively.

[0033] In some embodiments, the operating circuit 210 may include a first terminal 210A and a second terminal 210B. The first terminal 210A may be electrically connected to the cathode of the first photodiode 211. The second terminal 210B may be electrically connected to the anode of the first photodiode 211. Electrical connection may refer to a direct connection or an indirect connection through other components.

[0034] When the operating circuit 210 is in operation, the voltage applied to the first terminal 210A can be higher than the voltage applied to the second terminal 210B. For example, the second terminal 210B is grounded, and the first terminal 210A is connected to a forward voltage. The anode of the first photodiode 211 is connected to a low voltage, and the cathode is connected to a high voltage. The first photodiode 211 is in a reverse bias state. As the reverse voltage across the first photodiode 211 continuously increases, the first photodiode 211 can be reverse-biased, thereby detecting photons. The operating circuit 210 is configured to detect echoes at the operating voltage. The operating voltage refers to the voltage range within which the operating circuit 210 can operate normally. The operating voltage can be represented by the voltage difference between the first terminal 210A and the second terminal 210B. For example, the photodiode can only respond normally to received photons and generate electrical signals within a certain voltage range. If the voltage applied across the photodiode exceeds this voltage range, the PN junction of the photodiode may be broken down, damaging the device.

[0035] The operating voltage can be determined based on the specific application or the device being used. For example, for an APD operating in Geiger mode, the operating voltage applied across the APD generally needs to be greater than its reverse bias breakdown voltage (BV). Conversely, for an APD operating in linear mode, the operating voltage applied across the APD is generally less than its BV. However, if the operating voltage applied across the APD exceeds its BV, it may break down the APD's PN junction, damaging the device.

[0036] In some embodiments, the operating voltage is the voltage difference between the first terminal 210A and the second terminal 210B when the first photodiode 211 undergoes reverse breakdown. When the operating voltage is increased to the point that the first photodiode 211 undergoes reverse breakdown, the first photodiode 211 can sensitively detect photons. In some embodiments, the operating voltage is equal to the base voltage (BV) of the first photodiode 211. In some embodiments, the operating voltage may also be greater than the base voltage (BV) of the first photodiode 211. For example, the operating voltage may be greater than or equal to the sum of BV and overvoltage (OV), thereby enabling the first photodiode 211 to be in a state capable of sensitively detecting photons. For example, the operating voltage may be the sum of BV and OV. Here, OV can be from a few volts (V) to tens of volts.

[0037] In some embodiments, the operating circuit 210 further includes a quenching circuit 213. The quenching circuit 213 may be connected in series with the first photodiode 211. For example, please refer to... Figure 2The working circuit 210 may include multiple quenching circuits 213. One quenching circuit 213 is connected in series with a first photodiode 211. The first terminal 210A of the working circuit 210 is electrically connected to the quenching circuit 213, and the second terminal 210B of the working circuit 210 is electrically connected to the first photodiode 211.

[0038] The quenching circuit 213 is configured to restore the bias voltage of the first photodiode 211 after the first photodiode 211 experiences an avalanche effect. For example, after the first photodiode 211 experiences an avalanche, the quenching circuit 213 can reduce the voltage across the first photodiode 211, thereby preventing it from continuing to avalanche.

[0039] In some embodiments, the quenching circuit 213 includes a quenching resistor. For example, a SiPM chip has a structure where the APD is connected in series with the quenching resistor. Please refer to [link to relevant documentation]. Figure 2 A quenching resistor can be connected in series with the first photodiode 211.

[0040] In some embodiments, the quenching circuit 213 may include a metal-oxide-semiconductor field-effect transistor (MOSFET). The MOSFET can utilize its voltage control function to rapidly reduce the reverse bias voltage of the APD during avalanche, achieving rapid quenching and thus reducing the device recovery time.

[0041] The protection circuit 230 is connected in parallel with the working circuit 210. The two ends of the protection circuit 230 can be electrically connected to the first end 210A and the second end 210B of the working circuit 210, respectively. For example, the first end of the protection circuit 230 is electrically connected to the first end 210A of the working circuit 210, and the second end of the protection circuit 230 is electrically connected to the working circuit 210B.

[0042] In some embodiments, when the working circuit 210 includes a first photodiode 211, the protection circuit 230 can be connected in parallel with the two ends of the first photodiode 211 to protect the working circuit 210. In some embodiments, when the working circuit 210 further includes a quenching circuit 213, the first end of the protection circuit 230 can be electrically connected to the first photodiode 211, and the second end of the protection circuit 230 can be electrically connected to the quenching circuit 213. In this way, the entire working circuit 210 can be protected. In some embodiments, the circuit 200 may also include other circuit structures. The protection circuit 230 may also protect some of the other circuit structures. The specific structures of the other circuits will be described later.

[0043] The forward voltage of the protection circuit 230 is greater than the operating voltage, and the impedance of the protection circuit 230 after it is turned on is less than the impedance of the operating circuit 210 after it is turned on. The impedance can be an equivalent impedance. When the operating circuit 210 is working, the operating voltage is applied to it. Because the forward voltage of the protection circuit 230 is greater than the operating voltage, the protection circuit 230 is not turned on at this time. The protection circuit 230 is in the open state. Thus, when the operating circuit 210 is working, the protection circuit 230 will not affect its normal operation. When an ESD phenomenon occurs, there may be a voltage in the circuit that is much higher than the operating voltage, and there may also be a large instantaneous current in the circuit. This often leads to permanent damage to the circuit or circuit components, thus affecting the circuit's function. For example, when an electrostatic voltage is applied across the operating circuit 210, the electrostatic voltage is usually higher than the damage voltage of the first photodiode 211 itself. This may cause the first photodiode 211 to break down and suffer irreversible damage. The first photodiode 211 cannot work normally, thus affecting the normal operation of the lidar 10. After setting up the protection circuit 230, since it is connected in parallel with the working circuit 210, when an ESD phenomenon occurs, the electrostatic voltage will be applied to the protection circuit 230 simultaneously. Because the electrostatic voltage is much higher than the working voltage, the protection circuit 230 is turned on. The impedance of the working circuit 210 after it is turned on is at least the impedance of the quenching resistor. The impedance of the protection circuit 230 after it is turned on is much smaller than that of the working circuit 210, thus providing a low-impedance conduction path for the instantaneous large current. This allows more of the instantaneous large current to be diverted to the protection circuit 230, thereby clamping the high voltage generated by ESD within a lower voltage range. The voltage applied to the working circuit 210 is also clamped within a lower voltage range. By setting up a high-voltage, low-impedance protection circuit 230, the degree of damage caused by ESD to the working circuit 210 can be reduced.

[0044] Figure 3 A structural example diagram of a protection circuit consistent with some embodiments of this disclosure is shown. Please refer to... Figure 3 The protection circuit 230 includes a second photodiode 231. In some embodiments, the forward voltage of the protection circuit 230 may be the voltage that causes the second photodiode 231 to break down in reverse. For example, when there is only one second photodiode 231 in the protection circuit 230, the forward voltage of the protection circuit 230 is the BV of the second photodiode 231.

[0045] In some embodiments, the vertical distribution of doped ions in the second photodiode 231 is consistent with that in the first photodiode 211. Consistent vertical distribution of doped ions can mean that the manufacturing process steps of the first photodiode 211 and the second photodiode 231 are the same along the vertical direction of the diode, or that one manufacturing process step is a subset of the other's manufacturing process steps. For example, the first photodiode 211 and the second photodiode 231 may have the same doped ion concentration, the same doped ion depth, or the same relative position of the doped ion regions along the vertical direction. Thus, if both the operating circuit 210 and the protection circuit 230 are part of an integrated circuit formed on a chip substrate, the first photodiode 211 and the second photodiode 231 can be generated simultaneously through the same process steps, without needing to design one or more separate process steps for each photodiode, thereby simplifying the chip manufacturing process and saving chip manufacturing costs.

[0046] In some embodiments, the first photodiode 211 and the second photodiode 231 have identical physical structures. For example, except for the vertical distribution of doped ions, the lateral distribution of doped ions in the first photodiode 211 and the second photodiode 231 is also identical. The first photodiode 211 and the second photodiode 231 are completely identical. For example, the first photodiode 211 and the second photodiode 231 are of the same type and the same APD. The BV of the first photodiode 211 and the second photodiode 231 are the same. That is, the existing first photodiode 211, which is used for echo detection, is used as the second photodiode 231. Because the existing device is used as the ESD protection device, there is no need to develop a new ESD protection device, and the design and manufacturing costs of the device are not increased, nor are any process steps added.

[0047] In some embodiments, the lateral distribution of doped ions in the first photodiode 211 and the second photodiode 231 differs. For example, the lateral area of ​​the doped ion region in the second photodiode 231 is larger to increase the upper limit of current flow. For example, the mask area used in manufacturing the first photodiode 211 is modified when manufacturing the second photodiode 231. This increases the upper limit of current flow in the second photodiode 231 by increasing the ion-doped region. Because this is an ESD protection device derived from an existing device, the increase in process design and manufacturing costs is minimal.

[0048] SiPM and SPAD chips inherently possess photodiode structures. Therefore, their existing photodiode structures can be used as ESD protection devices. This eliminates the need for developing dedicated ESD protection devices and incurring additional process steps, thus reducing design and manufacturing costs. Furthermore, the photodiodes in SiPM and SPAD chips are vertically conductive, offering stronger current-carrying capacity compared to diodes with lateral conductive structures. They also offer advantages in terms of circuit and chip area, requiring less space.

[0049] In some embodiments, the second photodiode 231 may include a plurality of photodiodes connected in series. These plurality of photodiodes may include at least one reverse-biased photodiode. By providing a plurality of photodiodes connected in series, the turn-on voltage of the protection circuit 230 can be increased. In this way, the protection circuit 230 is not turned on under the operating voltage, thus not affecting the normal operation of the operating circuit 210.

[0050] In some embodiments, the plurality of series-connected photodiodes includes at least two reverse-biased photodiodes. For example, the second photodiode 231 includes three series-connected, reverse-biased photodiodes. As another example, the second photodiode 231 includes two series-connected, reverse-biased photodiodes. Please refer to... Figure 3 As shown, the second photodiode 231 includes two reverse-biased photodiodes. For example, the BV of one photodiode is approximately 20V, and the impedance of the photodiode after breakdown is approximately 5 ohms (Ω) to 10 Ω. The quenching resistor has a resistance of 150 kiloohms (KΩ). The operating voltage of the working circuit 210 is 25V, and the impedance of the working circuit 210 after conduction is approximately 150KΩ. Figure 3 The turn-on voltage of the protection circuit 230 is approximately 40V, and the impedance of the protection circuit 230 after it is turned on is approximately 10Ω to 20Ω. Therefore, the turn-on voltage of the protection circuit 230 is greater than the operating voltage, and the impedance of the protection circuit 230 after it is turned on is less than the impedance of the operating circuit 210 after it is turned on.

[0051] Under operating voltage, the operating circuit 210 is turned on while the protection circuit 230 is not turned on; therefore, the protection circuit 230 does not affect the normal operation of the operating circuit 210. In the event of ESD, the protection circuit 230 is turned on. Since the impedance of the protection circuit 230 (e.g., 10Ω to 20Ω) is much smaller than the impedance of the operating circuit 210 after it is turned on (e.g., 150KΩ), the protection circuit 230 is approximately a short circuit. The instantaneous large current is more significantly diverted to the protection circuit 230, thus reducing the extent of ESD damage to the operating circuit 210.

[0052] In some embodiments, the plurality of photodiodes connected in series may also include a reverse-biased photodiode and a plurality of forward-biased photodiodes. Figure 4 A structural example diagram of a protection circuit consistent with some embodiments of this disclosure is shown. Please refer to... Figure 4 The second photodiode 231 includes one reverse-biased photodiode and twenty forward-biased photodiodes. Figure 4 (Only five forward-biased photodiodes are shown.) For example, the BV of a photodiode is approximately 20V, and the impedance of a photodiode after breakdown is approximately 5Ω to 10Ω. The forward turn-on voltage of a photodiode is approximately 0.7V, and the impedance after forward conduction is approximately 50Ω. The quenching resistor has a resistance of 150KΩ. Correspondingly, the impedance of the working circuit 210 after conduction is approximately 150KΩ, and the operating voltage of the working circuit 210 is 25V. Figure 4 The turn-on voltage of the protection circuit 230 is approximately 34V, and the impedance of the protection circuit 230 after it is turned on is approximately 1.005KΩ to 1.01KΩ. Therefore, the turn-on voltage of the protection circuit 230 is greater than the operating voltage, and the impedance of the protection circuit 230 after it is turned on is less than the impedance of the operating circuit 210 after it is turned on.

[0053] Under operating voltage, protection circuit 230 is not activated and does not affect the normal operation of operating circuit 210. Under electrostatic discharge (ESD) voltage, protection circuit 230 is activated. Because the impedance of protection circuit 230 (e.g., 1.005KΩ to 1.01KΩ) is less than the impedance of operating circuit 210 after activation (e.g., 150KΩ), more of the instantaneous large current is diverted to protection circuit 230. Therefore, protection circuit 230 can reduce the extent of ESD damage to operating circuit 210, or prevent operating circuit 210 from being damaged.

[0054] The number of second photodiodes 231 can be determined according to requirements such as circuit cost, chip area, and board layout area, provided that the protection circuit 230 has a high forward voltage and low impedance. For example, the working circuit 210 includes M photodiodes connected in parallel and M quenching resistors. One quenching resistor is connected in series with one photodiode. The protection circuit 230 includes N photodiodes connected in series. Among them, N1 are reverse-biased photodiodes and N2 are forward-biased photodiodes. N, N1, and N2 are all positive integers, and N = N1 + N2. The BV of the reverse-biased photodiode is V. BV The 0V of a reverse-biased photodiode is V. OV The impedance after breakdown is R BR The forward turn-on voltage of a forward-biased photodiode is U. ON The impedance is R ON The on-state voltage of protection circuit 230 is N1 × V. BV +N2×U ON The impedance of the protection circuit 230 after it is turned on is N1×R BR +N2×R ON The operating voltage of the working circuit 210 is V. BV +V OV The impedance of the quenching resistor is R. CU The impedance of the working circuit 210 after it is turned on is (R CU +R BR For example, protection circuit 230 includes N photodiodes connected in series. Operating circuit 210 includes one photodiode and a quenching resistor connected in series with the photodiode. The on-state voltage of protection circuit 230 is N1 × V. BV +N2×U ON The impedance of the protection circuit 230 after it is turned on is N1×R BR +N2×R ON The operating voltage of the working circuit 210 is V. BV +V OV The impedance of the quenching resistor is R. CU The impedance of the working circuit 210 after it is turned on is R. CU +R BR .

[0055] The protection circuit 230 can have a high forward voltage; under the operating voltage, the protection circuit 230 does not affect the normal operation of the operating circuit 210. Operating voltage (e.g., V...) BV +V OV () less than the forward voltage (e.g., N1×V) BV +N2×U ONThe protection circuit 230 needs to have low impedance, providing a low-impedance conduction path for transient large currents. Therefore, the impedance of the protection circuit 230 after conduction (e.g., N1×R) is... BR +N2×R ON The impedance is less than the impedance after the working circuit 230 is turned on (for example, (R)). CU +R BR The specific values ​​of N1 and N2 can be selected according to different needs after satisfying the above relationship.

[0056] In some embodiments, the protection circuit 230 may include multiple branches, thereby increasing the upper limit of the current flowing through the protection circuit 230. Figure 5 A structural example diagram of a protection circuit consistent with some embodiments of this disclosure is shown. Please refer to... Figure 5 The protection circuit 230 may include a first protection circuit 235 and a second protection circuit 237 connected in parallel with the first protection circuit 235.

[0057] The first protection circuit 235 may include the second photodiode 231 described above. The second protection circuit may include a third photodiode 233. The structure and performance of the third photodiode 233 may be the same as or similar to that of the second photodiode. For example, both the second photodiode 231 and the third photodiode 233 may be photodiodes with the same physical structure as the first photodiode 211. As another example, the second photodiode 231 may be a photodiode with the same physical structure as the first photodiode 211. The lateral distribution of doped ions in the third photodiode 233 differs from that in the first photodiode 211. The structure and performance of the third photodiode 233 can be referred to the above description of the second photodiode 231, and will not be repeated here.

[0058] The impedance of the first protection circuit 235 after it is turned on is less than the impedance of the working circuit 210 after it is turned on. The impedance of the second protection circuit 237 after it is turned on is also less than the impedance of the working circuit 210 after it is turned on. Both the first protection circuit 235 and the second protection circuit 237 can provide a low-impedance conduction path for instantaneous large currents. This will cause more of the instantaneous large current to be diverted to the two protection circuits 230, while clamping the high voltage generated by ESD within a lower voltage range.

[0059] The circuit structures of the first protection circuit 235 and the second protection circuit 237 can be the same or different. In some embodiments, the circuit structures of the first protection circuit 235 and the second protection circuit 237 are the same. For example, the first protection circuit 235 includes two reverse-biased second photodiodes 231; the second protection circuit 237 also includes two reverse-biased third photodiodes 233. In some embodiments, the circuit structures of the first protection circuit 235 and the second protection circuit 237 are different. For example, please refer to... Figure 5 The first protection circuit 235 includes three reverse-biased second photodiodes 231; the second protection circuit 237 includes two reverse-biased third photodiodes 233. For example, the first protection circuit 235 may include three reverse-biased second photodiodes 231, and the second protection circuit 237 may include two reverse-biased third photodiodes 233 and fifteen forward-biased third photodiodes 233. Although the forward voltage of the second protection circuit 237 is slightly higher than that of the first protection circuit 235, both protection circuits 230 can be turned on when the electrostatic voltage is high. Therefore, both the first protection circuit 235 and the second protection circuit 237 can protect the working circuit 210.

[0060] In some embodiments, the protection circuit 230 may include more branches. For example, the protection circuit 230 may also include a third protection circuit, a fourth protection circuit, and so on. The structures of different branches of the protection circuit 230 may be the same or different.

[0061] By setting up multiple protection circuits 230, multiple low-impedance conduction paths can be provided for instantaneous high currents, thereby increasing the upper limit of current that the protection circuit 230 can carry. By setting up multiple protection circuits 230, more instantaneous high currents can be diverted to the protection circuits 230, thereby providing more reliable protection for the operating circuit 210.

[0062] In some embodiments, circuit 200 further includes a substrate. The operating circuit 210 and protection circuit 230 may be formed on the substrate. For example, circuit 200 may include a silicon substrate. As another example, circuit 200 may include a P-substrate. For example, a first photodiode 211 is formed on the substrate, and a second photodiode 231 is formed on the substrate. The area occupied by the second photodiode 231 on the substrate is smaller than the area occupied by the first photodiode 211. Therefore, using the second photodiode 231 as an ESD protection device does not increase area cost excessively and can improve the integration and yield of the circuit or chip.

[0063] Circuit 200 may also include other circuit structures. In some embodiments, circuit 200 may further include a control circuit and a readout circuit. The control circuit may be configured to provide a stable bias voltage, perform temperature compensation and gain control to improve the reliability of the lidar 10's detection performance. The readout circuit may be configured to read out the output signal of the first photodiode 211. There are interconnections between the operating circuit 210, the control circuit, the readout circuit, and the quenching circuit.

[0064] In some embodiments, the operating circuit 210 may include a quenching circuit 213. The quenching circuit 213, as part of the operating circuit 210, is also connected in parallel with the protection circuit 230. Therefore, the protection circuit 230 can protect the quenching circuit 213 together. For example, in a SiPM chip, the operating circuit 210 includes a photodiode and a quenching resistor. In a SiPM chip, the control circuit and the readout circuit are not directly connected in parallel to the protection circuit 230. For example, the readout circuit and the control circuit are not integrated into the SiPM chip itself, but are designed externally to the SiPM chip. As another example, a port is led out between the photodiode and the quenching circuit; this port is used to read data.

[0065] Figure 6 A schematic diagram illustrating the structure of a circuit consistent with some embodiments of this disclosure is shown. Please refer to... Figure 6 Circuit 200 may include a readout circuit 270. One end of the readout circuit 270 is electrically connected between the first photodiode 211 and the quenching circuit 213. It is worth noting that circuit 200 may include one readout circuit 270, and multiple first photodiodes 211 may share one readout circuit 270. Circuit 200 may also include multiple readout circuits 270, with each readout circuit 270 electrically connected to its corresponding first photodiode 211.

[0066] In some embodiments, the quenching circuit is not connected in parallel with the protection circuit 230. To distinguish it from the quenching circuit 213 described above, the quenching circuit is treated as a separate circuit section and is referred to as quenching circuit 250. Figure 7 A schematic diagram illustrating the structure of a circuit consistent with some embodiments of this disclosure is shown. Please refer to... Figure 7In addition to the operating circuit 210 and the protection circuit 230, circuit 200 also includes a quenching circuit 250. The quenching circuit 250 can be configured to restore the bias voltage of the first photodiode 211 after an avalanche effect occurs. The quenching circuit 250 can reduce the voltage across the first photodiode 211, thereby preventing it from continuing to avalanche. For example, in a SPAD chip, circuit 200 includes an operating circuit 210, a protection circuit 230, and a quenching circuit 250. In some embodiments, the quenching circuit 250 may include a quenching resistor. In some embodiments, the quenching circuit 250 may include a metal-oxide-semiconductor field-effect transistor (MOSFET). The MOSFET can utilize its voltage control function to rapidly reduce the reverse bias voltage of the APD during an avalanche, achieving rapid quenching and thus reducing the device recovery time.

[0067] Please refer to Figure 7 The first terminal 250A of the quenching circuit 250 can be connected to one end of the working circuit 210, and the first terminal 250A of the quenching circuit 250 can be connected to one end of the protection circuit 230. The quenching circuit 250 is not connected in parallel with the protection circuit 230. The protection circuit 230 is connected in parallel only with the working circuit 210, and only provides electrostatic protection for the first photodiode 211.

[0068] In some embodiments, please refer to Figure 7 Circuit 200 may also include readout circuit 270 and control circuit 290. Operating circuit 210, protection circuit 230, quenching circuit 250, readout circuit 270, and control circuit 290 can all be integrated onto the SPAD chip. As an example, Figure 7 The diagram illustrates the connection relationship between a working circuit 210, a quenching circuit 250, a readout circuit 270, and a control circuit 290. Multiple first photodiodes 211 are connected in series with multiple quenching circuits 250. For example, one first photodiode 211 is connected in series with one quenching circuit 250. The multiple quenching circuits 250 are also electrically connected to multiple readout circuits 270. The multiple quenching circuits 250 are electrically connected to a control circuit 290. One end of the control circuit 290 is electrically connected to the multiple quenching circuits 250, and the other end can receive a voltage (Power) to drive the circuit 200.

[0069] Figure 8 A schematic diagram of a circuit structure consistent with some embodiments of this disclosure is shown. Figure 8 The diagram illustrates the connection relationship between another operating circuit 210, quenching circuit 250, readout circuit 270, and control circuit 290. Please refer to [the diagram / reference]. Figure 8One end of each of the multiple quenching circuits 250 is electrically connected to a readout circuit 270. The other end of each of the multiple first photodiodes 211 is connected in series with the multiple quenching circuits 250. The multiple quenching circuits 250 are electrically connected to a control circuit 290. One end of the control circuit 290 is electrically connected to the multiple quenching circuits 250, and the other end can receive a voltage Power, thereby driving the circuit 200 to work.

[0070] Figure 9 A schematic diagram of a circuit structure consistent with some embodiments of this disclosure is shown. Figure 9 The diagram illustrates the connection relationship between another type of operating circuit 210, quenching circuit 250, readout circuit 270, and control circuit 290. Please refer to [the diagram / reference]. Figure 9 Multiple first photodiodes 211 are connected in series with multiple quenching circuits 250. The multiple quenching circuits 250 are electrically connected to a readout circuit 270. The readout circuit 270 is then connected in series with a control circuit 290. One end of the control circuit 290 is electrically connected to the readout circuit 270, and the other end can receive voltage Power, thereby driving the circuit 200 to work.

[0071] In some embodiments, the quenching circuit 250, the readout circuit 270, and the control circuit 290 may not be connected in parallel with the protection circuit 230. In some embodiments, at least one of the quenching circuit 250, the readout circuit 270, or the control circuit 290 may be connected in parallel with the protection circuit 230. Figure 9 The quenching circuit 250, readout circuit 270, and control circuit 290 shown are used as examples for introduction.

[0072] Figure 10 A schematic diagram illustrating the structure of a circuit consistent with some embodiments of this disclosure is shown. Please refer to... Figure 10 The working circuit 210 and the quenching circuit 250 can be connected in parallel with the protection circuit 230. The protection circuit 230 can protect both the working circuit 210 and the quenching circuit 250 simultaneously.

[0073] Figure 11 A schematic diagram illustrating the structure of a circuit consistent with some embodiments of this disclosure is shown. Please refer to... Figure 11 The working circuit 210, the quenching circuit 250, and the readout circuit 270 can be connected in parallel with the protection circuit 230. The protection circuit 230 can simultaneously protect the working circuit 210, the quenching circuit 250, and the readout circuit 270.

[0074] Figure 12 A schematic diagram illustrating the structure of a circuit consistent with some embodiments of this disclosure is shown. Please refer to... Figure 12The working circuit 210, quenching circuit 250, readout circuit 270, and control circuit 290 can all be connected in parallel with the protection circuit 230. The protection circuit 230 can simultaneously protect the working circuit 210, quenching circuit 250, readout circuit 270, and control circuit 290.

[0075] This disclosure also provides a lidar 10. The lidar 10 includes a laser 100 and circuitry 200 for laser detection. The laser 100 is configured to emit laser light during operation. The laser detection circuitry 200 is configured to receive the echo corresponding to the laser light during operation. The laser detection circuitry 200 can be one of the aforementioned... Figures 1 to 12 The circuit 200 provided in the corresponding embodiment.

[0076] This disclosure also provides a vehicle 30. Figure 13 A structural example diagram of a vehicle consistent with some embodiments of this disclosure is shown. Please refer to... Figure 13 As shown, the vehicle 30 includes a lidar 10 and a connector 40. The connector 40 is used to connect the lidar 10 and the vehicle 30.

[0077] The lidar 10 can be understood as described above. Figure 1 The corresponding embodiment provides a lidar 10. In some embodiments, the vehicle 30 may be a means of transportation. For example, the vehicle 30 may be a vehicle, an airplane, or a ship, etc. In some embodiments, the vehicle 30 may also be an intelligent machine. For example, the vehicle 30 may be a robotic vacuum cleaner or a food delivery robot, etc. This disclosure does not limit the scope of the invention.

[0078] Connector 40 is configured to connect lidar 10 and vehicle 30. In some embodiments, connector 40 is a snap-fit ​​and slot structure. A snap-fit ​​is provided on one of lidar 10 or vehicle 30. A slot adapted to the snap-fit ​​is provided on the other of lidar 10 or vehicle 30. The lidar 10 can be fixed to vehicle 30 by the snap-fit ​​and slot engagement. In some embodiments, connector 40 is a magnetic assembly. The magnetic assembly can be provided on lidar 10 or vehicle 30. The lidar 10 is fixed to the vehicle by magnetic attraction. Taking vehicle 30 as an example, in some embodiments, please refer to... Figure 13 The lidar 10 can be fixedly or detachably mounted on the roof of the vehicle via connector 40. In some embodiments, the lidar 10 can be fixedly or detachably mounted on the rear side of the windshield inside the vehicle via connector 40.

[0079] In summary, the circuit 200 provided in this disclosure, by setting a protection circuit 230 with a high on-state voltage and low on-state impedance, can reduce the degree of damage caused by ESD to the working circuit 210. Specifically, since the on-state voltage of the protection circuit 230 is greater than the working voltage, the protection circuit 230 is not conducting when the working circuit 210 is working. Thus, the protection circuit 230 does not affect the normal operation of the working circuit 210. When an ESD event occurs, an electrostatic voltage is simultaneously applied to the protection circuit 230. The higher electrostatic voltage causes the protection circuit 230 to conduct. Since the impedance of the protection circuit 230 after conduction is less than the impedance of the working circuit 210 after conduction, the protection circuit 230 can provide a low-impedance conduction path for instantaneous large currents. This allows more of the instantaneous large current to be shunted to the protection circuit 230, and the voltage across the working circuit 210 is clamped within a lower voltage range. By setting a protection circuit 230 with a high on-state voltage and low impedance, the degree of damage caused by ESD to the working circuit 210 can be reduced. The doped ions of the first photodiode 211 and the second photodiode 231 have the same vertical distribution. This means that the second photodiode 231 can be obtained based on the process steps of the first photodiode 211 without additional or only minor modifications to the process steps. Thus, the design or manufacturing cost of the circuit is increased with little or no increase.

[0080] The foregoing has described specific embodiments of this disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0081] In summary, after reading this detailed disclosure, those skilled in the art will understand that the foregoing detailed disclosure may be presented by way of example only and may not be restrictive. Although not explicitly stated herein, those skilled in the art will understand that the requirements of this disclosure encompass various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are intended to be made by this disclosure and are within the spirit and scope of the exemplary embodiments of this disclosure.

[0082] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this disclosure, are intended to cover non-exclusive inclusion. In the description of embodiments of this disclosure, technical terms such as "first," "second," etc., are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of embodiments of this disclosure, "a plurality of" means two or more, unless otherwise expressly and specifically defined.

[0083] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0084] In view of the following description, these and other features of this disclosure, as well as the operation and function of the related elements of the structure, and the economy of assembly and manufacture of the components, can be significantly improved. All of these form part of this disclosure with reference to the accompanying drawings. However, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this disclosure. It should also be understood that the drawings are not drawn to scale.

[0085] The flowcharts used in this disclosure illustrate operations implemented according to some embodiments of this disclosure. It should be clearly understood that the operations in the flowcharts may not be implemented sequentially. Instead, the operations may be implemented in reverse order or simultaneously. Furthermore, one or more additional operations may be added to the flowcharts. One or more operations may be removed from the flowcharts.

[0086] In this disclosure, "X includes at least one of A, B, or C" means that X includes at least A, or X includes at least B, or X includes at least C. That is, X can include only one of A, B, and C, or any combination of A, B, and C, as well as other possible content or elements. The arbitrary combination of A, B, and C can be A, B, C, AB, AC, BC, or ABC.

[0087] In this disclosure, "or" describes the association relationship between related objects, representing a non-exclusive inclusion. For example, each of "A or B" can include: only "A" exists, only "B" exists, and both "A" and "B" exist, where "A" and "B" can be singular or plural. As another example, "A, B or C" can include: only "A" exists, only "B" exists, only "C" exists, both "A" and "B" exist, both "A" and "C" exist, both "B" and "C" exist, and all "A", "B" and "C" exist, where "A", "B" and "C" can be singular or plural.

[0088] In this disclosure, "X includes at least one of A, B, or C" means that X includes at least A, or X includes at least B, or X includes at least C. That is, X can include only one of A, B, and C, or any combination of A, B, and C, as well as other possible content / elements. The arbitrary combination of A, B, and C can be A, B, C, AB, AC, BC, or ABC.

[0089] In this disclosure, unless explicitly stated otherwise, the relationships between structures can be direct or indirect. For example, when describing "A is connected to B," unless it is explicitly stated that A and B are directly connected, it should be understood that A can be directly connected to B or indirectly connected to B. Similarly, when describing "A is above B," unless it is explicitly stated that A is directly above B (AB is adjacent and A is above B), it should be understood that A can be directly above B or indirectly above B (AB is separated by other elements, and A is above B). And so on. When describing "A is inside B," unless it is explicitly stated that A is entirely inside B, it should be understood that all of A can be inside B, and some of A can also be inside B.

[0090] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. The present disclosure will now be described in detail.

[0091] Furthermore, certain terms used in this disclosure have been used to describe embodiments of this disclosure. For example, "an embodiment," "an embodiment," and / or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with that embodiment may be included in at least one embodiment of this disclosure. Therefore, it is to be emphasized and understood that two or more references to "an embodiment" or "an embodiment" or "alternative embodiment" in various parts of this disclosure do not necessarily refer to the same embodiment. Moreover, specific features, structures, or characteristics may be suitably combined in one or more embodiments of this disclosure.

[0092] It should be understood that in the foregoing description of the embodiments of this disclosure, various features are combined in a single embodiment, drawing, or description for the purpose of simplifying the disclosure and to aid in understanding a feature. However, this does not mean that the combination of these features is necessary, and those skilled in the art, upon reading this disclosure, may readily identify some of the devices as separate embodiments. That is, the embodiments in this disclosure can also be understood as an integration of multiple secondary embodiments. It is also valid when each secondary embodiment contains fewer than all the features of a single foregoing disclosed embodiment.

[0093] Every patent, patent application, publication of a patent application, and other material such as articles, books, specifications, publications, documents, articles, etc., cited herein, except for any related historical prosecution documents, any identical ones that may be inconsistent with or conflict with this document, or any identical historical prosecution documents that may have a limiting effect on the widest scope of the claims, may be incorporated herein by reference and used for all purposes now or hereafter in connection with this document. Furthermore, in the event of any inconsistency or conflict between the description, definition, and / or use of terms related to any included material and those related to this document, the terminology used herein shall prevail.

[0094] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments of this disclosure. Other modified embodiments are also within the scope of this disclosure. Therefore, the embodiments disclosed herein are merely examples and not limitations. Those skilled in the art can implement the applications of this disclosure using alternative configurations based on the embodiments in this disclosure. Therefore, the embodiments of this disclosure are not limited to the embodiments precisely described in the applications.

Claims

1. A circuit for laser detection, characterized in that, include: The operating circuit includes a first photodiode and is configured to detect echoes at an operating voltage; A protection circuit connected in parallel with the working circuit includes a second photodiode, wherein the doped ions of the second photodiode are longitudinally distributed in the same direction as those of the first photodiode. The on-state voltage of the protection circuit is greater than the operating voltage, and the impedance of the protection circuit after it is turned on is less than the impedance of the operating circuit after it is turned on.

2. The circuit according to claim 1, characterized in that, The second photodiode includes a plurality of photodiodes connected in series, wherein the plurality of photodiodes connected in series includes at least one reverse-biased photodiode.

3. The circuit according to claim 2, characterized in that, The plurality of series-connected photodiodes include at least two reverse-biased photodiodes.

4. The circuit according to claim 2, characterized in that, The plurality of photodiodes connected in series includes one reverse-biased photodiode and a plurality of forward-biased photodiodes.

5. The circuit according to any one of claims 1-4, characterized in that, It also includes a substrate; wherein, The working circuit and the protection circuit are formed on the substrate; The area occupied by the second photodiode on the substrate is smaller than the area occupied by the first photodiode on the substrate.

6. The circuit according to any one of claims 1-5, characterized in that, The protection circuit includes a first protection circuit and a second protection circuit connected in parallel with the first protection circuit; wherein, The first protection circuit includes the second photodiode; The second protection circuit includes a third photodiode; The doped ions of the second photodiode and the third photodiode have the same vertical distribution; The impedance of the first protection circuit after it is turned on is less than the impedance of the working circuit after it is turned on, and the impedance of the second protection circuit after it is turned on is less than the impedance of the working circuit after it is turned on.

7. The circuit according to any one of claims 1-6, characterized in that, The working circuit also includes a quenching circuit; The quenching circuit is connected in series with the first photodiode; The quenching circuit is configured to restore the bias voltage of the first photodiode after the first photodiode experiences an avalanche effect.

8. The circuit according to any one of claims 1-6, characterized in that, The circuit also includes a quenching circuit; The quenching circuit is configured to restore the bias voltage of the first photodiode after the first photodiode experiences an avalanche effect. The first end of the quenching circuit is connected to one end of the working circuit, and the first end of the quenching circuit is connected to one end of the protection circuit.

9. The circuit according to any one of claims 7-8, characterized in that, The quenching circuit includes a quenching resistor or a metal-oxide-semiconductor field-effect transistor (MOS).

10. A lidar, characterized in that, Includes a laser, and a laser detection circuit as described in any one of claims 1-9; in The laser is configured to emit laser light when in operation; The laser detection circuit is configured to receive the echo corresponding to the laser when it is in operation.

11. A vehicle, characterized in that, Includes a connector, and a lidar as described in claim 10; wherein, The connector is used to connect the lidar and the vehicle.

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