A ranging device and a high voltage generating circuit thereof

Abstract

The application discloses a ranging device and a high-voltage generating circuit thereof, and applies to the technical field of ranging, and comprises a reference voltage generator for generating a reference voltage; a voltage stabilizing circuit connected with an output end of the reference voltage generator and used for maintaining output voltage HVout stable through a feedback loop of the voltage stabilizing circuit according to the reference voltage; a first resistor connected with a first power supply at a first end and connected with a power supply end of the reference voltage generator and a power supply end of the voltage stabilizing circuit at a second end, and used for reducing the value of the reference voltage and the value of the output voltage HVout through the first resistor. According to the scheme of the application, the sensitivity of the circuit can reach a suitable value under different ambient light, and then the accuracy of ranging can be ensured. Moreover, the scheme of the application does not appear over-regulation, and only needs to set the first resistor, so that the cost of the scheme is relatively low.

Description

Technical Field

[0001] This invention relates to the field of ranging technology, and in particular to a ranging device and its high-voltage generation circuit. Background Technology

[0002] In the process of dToF array ranging and imaging using SPAD (Single Photon Avalanche Diode) + TCSPC (Time-Correlated Single Photon Counting), it is necessary to induce avalanche in the diode operating in the Geiger state. (See [reference needed]). Figure 1 This is a simplified schematic diagram of the SPAD front end. It requires that the reverse bias voltage Vop across the PN junction of the diode be higher than the avalanche voltage Vbd. The voltage of the higher portion is generally called the overbias voltage Veb, i.e., Vop = Vbd + Veb. This controls the timing output of the subsequent TDC (Time-to-Digital Converter) circuit. The time of flight of light is calculated through this timing to achieve distance measurement.

[0003] Generally, the selection of Veb needs to take into account the device's fabrication process and structure. An excessively high Veb can lead to higher sensor noise, while an excessively low Veb can reduce sensor sensitivity. Photon detection efficiency (PDE) is typically used to evaluate device sensitivity. In practical applications, when ambient light is weak, it's generally desirable to increase PDE to improve the detection of low-reflectivity, distant targets. Conversely, when ambient light is strong, it's desirable to decrease PDE to reduce triggering caused by ambient light. These triggering events are meaningless for measurement and can cause side effects in backend processing, such as a decrease in signal-to-noise ratio.

[0004] See also Figure 2 In a certain situation, the following is adopted Figure 1 The statistical histograms under different ambient light conditions within the circuit architecture show that as ambient light increases, the noise floor becomes skewed (approaching an exponential relationship), making echo target identification more difficult on the histogram. This problem can be solved through a series of circuit designs, but this will increase cost and power consumption. Furthermore, ambient light triggering significantly increases circuit power consumption while consuming circuit bandwidth; actual tests show that high ambient light conditions can increase chip power consumption by up to the mW level.

[0005] See also Figure 3a, which is a schematic diagram of a common DTOF circuit architecture currently. Here, HVout is Vop (Vbd + Veb). For the above problems, there are several current solutions as follows: The first is to reduce pde, which will directly sacrifice the detectability of low light. In specific engineering implementations, a series of methods such as adding a metal layer barrier on the SPAD and adding an attenuation film can be adopted. The second solution can be referred to Figure 3b , which is a schematic diagram of a photosensitive adaptive circuit using an additional sensor to control the reference voltage. The third solution can be referred to Figure 3c , which is a schematic diagram of a photosensitive adaptive circuit using an additional sensor to control the bias voltage. Figure 3b And Figure 3c Both methods require an additional ambient light detector to adjust Veb according to the ambient light, resulting in a high cost. Figure 3d And Figure 3e Are schematic diagrams of two photosensitive adaptive circuits using a histogram for ambient light detection. The ambient light information is extracted from the histogram of the SPAD, and Veb is adjusted according to the ambient light. Figures 3b to 3e The biggest problem with

[0006] is that the compensation curve is difficult to control, that is, the Veb adjustment curve is difficult to define, which may lead to overcompensation, that is, Vop < Vbd, causing the module not to work. Summary of the Invention

[0007] The object of the present invention is to provide a ranging device and its high-voltage generation circuit, so as to make the sensitivity of the ranging device reach an appropriate value under different ambient lights, ensure the accuracy of ranging, and avoid over-adjustment.

[0008] To solve the above technical problems, the present invention provides the following technical solutions:

[0009] A high-voltage generation circuit includes:

[0010] A reference voltage generator for generating a reference voltage;

[0011] A voltage stabilizing circuit connected to the output end of the reference voltage generator, for maintaining the stability of the output voltage HVout according to the reference voltage through its own feedback loop;

[0012] A first resistor with its first end connected to a first power supply and its second end respectively connected to the power supply end of the reference voltage generator and the power supply end of the voltage stabilizing circuit, for reducing the value of the reference voltage and the value of the output voltage HVout through the first resistor.

[0013] Preferably, it also includes a first switch;

[0014] The first switch is connected in parallel with the first resistor;

[0015] When the ambient light is weak, the first switch closes and the first resistor is short-circuited; when the ambient light is strong, the first switch opens.

[0016] Preferably, the voltage regulator circuit includes: a first voltage divider circuit, a second voltage divider circuit, a comparator, and a charge pump;

[0017] The positive input terminal of the comparator is connected to the output terminal of the reference voltage generator, the negative input terminal of the comparator is connected to the common terminal of the first voltage divider circuit and the second voltage divider circuit, and the output terminal of the comparator is connected to the input terminal of the charge pump.

[0018] The power supply terminal of the charge pump serves as the power supply terminal of the voltage regulator circuit, and the output terminal of the charge pump serves as the output terminal of the voltage regulator circuit.

[0019] The first voltage divider circuit and the second voltage divider circuit are connected in series between the output terminal of the voltage regulator circuit and ground.

[0020] Preferably, the first voltage divider circuit includes a second resistor, and the second voltage divider circuit includes a third resistor;

[0021] The second resistor and the third resistor are connected in series between the output terminal of the voltage regulator circuit and ground.

[0022] Preferably, the first resistor is an adjustable resistor.

[0023] Preferably, the output voltage HVout is connected to the cathodes of multiple SPADs, and the anode of each SPAD is grounded through a MOS switch connected in series.

[0024] Preferably, it further includes: a second switch connected in series with the first resistor, and n resistor branches connected in parallel with the first resistor, where n is a positive integer;

[0025] Each of the resistor branches includes one resistor and a switch connected in series with the resistor; by controlling the switch of the resistor branch to close or open, the resistance value of the resistor connected in series between the first power supply and the power supply terminal of the reference voltage generator can be adjusted.

[0026] Preferably, the second switch and the switches in the n resistor branches are all MOSFET switches, with their gates controlled by the output of a register.

[0027] A ranging device includes a high-voltage generation circuit as described above.

[0028] The technical solution provided by this invention utilizes the instability of the reference voltage generator loop control to achieve adaptive control of HVout. Specifically, the reference voltage generator produces a reference voltage Vref. The voltage regulator circuit is connected to the output terminal of the reference voltage generator and can maintain the stability of the output voltage HVout based on the reference voltage Vref through its own feedback loop. When the ambient light increases, the number of SPAD triggers in the subsequent stage increases, so the output current of the voltage regulator circuit increases. Since this application sets a first resistor between the first power supply, the power supply terminal of the reference voltage generator, and the power supply terminal of the voltage regulator circuit, when the output current of the voltage regulator circuit increases, the voltage division of the first resistor increases, which in turn reduces the supply voltage Vin of the reference voltage generator. Theoretically, a decrease in the supply voltage Vin of the reference voltage generator should not affect the reference voltage Vref, meaning that the reference voltage Vref is generally considered a fixed value. However, this application utilizes the inherent instability of the reference voltage generator's loop control. It considers that when the supply voltage Vin changes significantly, the reference voltage generator's loop becomes unstable, leading to a decrease in the generator's output voltage, specifically a decrease in the output reference voltage Vref. This decrease in Vref causes a decrease in the output voltage HVout of the voltage regulator circuit, thus reducing Veb. Furthermore, when HVout drops to a certain level (below Vbd), the number of SPAD triggers approaches zero, reducing the voltage division of the first resistor and allowing the circuit to enter normal mode. Therefore, this application's solution avoids the situation where the entire circuit malfunctions due to over-adjustment of HVout.

[0029] In summary, the solution presented in this application utilizes the inherent instability of the reference voltage generator's loop control. By setting a first resistor, the reference voltage and output voltage HVout values ​​are reduced when ambient light is strong, thus lowering Veb. Therefore, the solution in this application allows the circuit's sensitivity to reach appropriate values ​​under different ambient light conditions, thereby ensuring accurate ranging. Furthermore, this solution avoids over-adjustment, and the requirement to set only a first resistor keeps the cost low. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a simplified structural diagram of the SPAD front end;

[0032] Figure 2 For use in a certain situation Figure 1 Statistical histograms of the circuit architecture under different ambient light conditions;

[0033] Figure 3a This is a schematic diagram of a common DTof circuit architecture.

[0034] Figure 3b This is a schematic diagram of a photosensitive adaptive circuit that currently uses an additional sensor to control the reference voltage.

[0035] Figure 3c This is a schematic diagram of a photosensitive adaptive circuit that currently uses an additional sensor to control the bias voltage.

[0036] Figure 3d This is a schematic diagram of a photosensitive adaptive circuit that uses histograms for ambient light detection.

[0037] Figure 3e This is a schematic diagram of another photosensitive adaptive circuit that uses histograms for ambient light detection.

[0038] Figure 4 This is a schematic diagram of a high-voltage generation circuit according to the present invention;

[0039] Figure 5 This is a schematic diagram of the high-voltage generation circuit in a specific embodiment of the present invention;

[0040] Figure 6 This is a schematic diagram of the high voltage generation circuit in another specific embodiment of the present invention;

[0041] Figure 7 This is a schematic diagram of the high-voltage generation circuit in another specific embodiment of the present invention;

[0042] Figure 8a This is a schematic diagram comparing histograms under low ambient light conditions in a specific embodiment of the present invention;

[0043] Figure 8b This is a schematic diagram comparing histograms under high ambient light conditions in a specific embodiment of the present invention. Detailed Implementation

[0044] The core of this invention is to provide a high-voltage generation circuit that can achieve appropriate sensitivity values ​​under different ambient light conditions, thereby helping to ensure the accuracy of distance measurement. Furthermore, this solution avoids over-adjustment, and the fact that only a first resistor is required also keeps the cost of the solution low.

[0045] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Please refer to Figure 4 , Figure 4 This is a schematic diagram of a high-voltage generation circuit according to the present invention. The high-voltage generation circuit may include:

[0047] Reference voltage generator 10 is used to generate a reference voltage;

[0048] A voltage regulator circuit 20 is connected to the output terminal of the reference voltage generator 10 and is used to maintain the output voltage HVout stable according to the reference voltage through its own feedback loop.

[0049] The first resistor R1, whose first end is connected to the first power supply and whose second end is connected to the power supply terminal of the reference voltage generator 10 and the power supply terminal of the voltage regulator circuit 20 respectively, is used to reduce the value of the reference voltage and the value of the output voltage HVout through the first resistor R1.

[0050] Specifically, the specific type of the reference voltage generator 10 used in this application and its internal circuit structure can be set and adjusted according to actual needs, as long as it can effectively generate the required reference voltage Vref. The specific value of the reference voltage Vref generated by the reference voltage generator 10 can also be set and adjusted according to actual needs, which will not be elaborated here.

[0051] The voltage regulator circuit 20 is connected to the output terminal of the reference voltage generator 10. Based on the reference voltage Vref, it maintains the stability of the output voltage HVout through its own feedback loop. Similarly, the specific type of the voltage regulator circuit 20 and its internal circuit structure can be set and adjusted according to actual needs. Typically, a comparator-based structure can easily and conveniently implement the feedback loop of the voltage regulator circuit 20.

[0052] For example, in one specific embodiment of the present invention, see [reference needed]. Figure 5 The voltage regulator circuit 20 may specifically include: a first voltage divider circuit, a second voltage divider circuit, a comparator 21, and a charge pump 22;

[0053] The positive input terminal of comparator 21 is connected to the output terminal of reference voltage generator 10, the negative input terminal of comparator 21 is connected to the common terminal of the first voltage divider circuit and the second voltage divider circuit, and the output terminal of comparator 21 is connected to the input terminal of charge pump 22.

[0054] The power supply terminal of the charge pump 22 serves as the power supply terminal of the voltage regulator circuit 20, and the output terminal of the charge pump 22 serves as the output terminal of the voltage regulator circuit 20.

[0055] The first voltage divider circuit and the second voltage divider circuit are connected in series between the output terminal of the voltage regulator circuit 20 and ground.

[0056] The first and second voltage divider circuits function as voltage dividers, typically implemented using resistors, which are low-cost and highly reliable. Specifically, the first voltage divider circuit includes a second resistor R2, and the second voltage divider circuit includes a third resistor R3; the second resistor R2 and the third resistor R3 are connected in series between the output terminal of the voltage regulator circuit 20 and ground. Figure 5 The implementation described herein employs this method. Of course, in other specific implementations, other circuit devices can be used to achieve the voltage division effect without affecting the implementation of this invention. Furthermore, it is understood that when using resistors to achieve voltage division, a single resistor can serve as the aforementioned second resistor R2, or multiple resistors can be combined in series / parallel to achieve an equivalent second resistor R2; the third resistor R3 follows the same principle.

[0057] exist Figure 5 In this embodiment, the first end of the second resistor R2 is connected to the output terminal of the charge pump 22, and this connection terminal serves as the output terminal of the voltage regulator circuit 20. The second end of the second resistor R2 is connected to the first end of the third resistor R3, and the second end of the third resistor R3 is grounded. The voltage at the connection point of the second resistor R2 and the third resistor R3 is... Figure 5 The middle is marked as V FB Under normal circumstances, V FB The error between the voltage and the reference voltage Vref is low or even zero, and the output voltage HVout of the voltage regulator circuit 20 is in a stable state.

[0058] The positive input terminal of comparator 21 is the reference voltage Vref, and the negative input terminal of comparator 21 is V... FB With the reference voltage Vref remaining constant, V FB Fluctuations can cause changes in the output voltage of comparator 21, which in turn causes changes in the output voltage HVout of charge pump 22, thereby restoring the output voltage HVout to stability through the principle of negative feedback.

[0059] This application provides a first resistor R1 with its first end connected to a first power supply and its second end connected to the power supply terminals of the reference voltage generator 10 and the voltage regulator circuit 20, respectively. This allows the reference voltage and the output voltage HVout to be reduced through the first resistor R1 when the ambient light is strong.

[0060] Specifically, the output of the voltage regulator circuit 20 is connected to a photosensitive circuit for photoelectric conversion, which is typically a SPAD photosensitive array. For example, in one specific embodiment of the present invention, the output voltage HVout is externally connected to the cathodes of multiple SPADs, and the anode of each SPAD is grounded through a MOS switch connected in series.

[0061] exist Figure 5 In this implementation, VQ represents the control signal of the grounded MOS switch connected in series with the corresponding SPAD. Through these MOS switches, the controller can control whether the corresponding SPAD is in an operational state. As described above, in practical applications, the photosensitive circuit is typically a SPAD photosensitive array. These arrays can enter the operational state sequentially according to a preset grouping, and the controller determines which SPADs are currently in an operational state through these MOS switches. Of course, the specific operating mode of the photosensitive circuit can be set and adjusted according to actual needs, which will not be elaborated upon in this application. Figure 5 In this implementation, three external SPADs are shown only at the output of the voltage regulator circuit 20.

[0062] When ambient light increases, the number of triggered SPADs in the SPAD photosensitive array increases, therefore Figure 5 An increase in i_spad, where i_spad represents the output current of the voltage regulator circuit 20, will cause an increase in the supply current of the voltage regulator circuit 20, that is... Figure 5 The increase in the supply current i_pump of the medium charge pump 22 leads to an increase in the voltage division of the first resistor R1, which in turn reduces the supply voltage Vin of the reference voltage generator 10.

[0063] Theoretically, a decrease in the supply voltage Vin of the reference voltage generator 10 will not affect the reference voltage Vref. However, this application considers that when the supply voltage Vin changes significantly, the loop of the reference voltage generator 10 will become unstable, which will lead to a decrease in the output voltage of the reference voltage generator 10, that is, a decrease in the reference voltage Vref output by the reference voltage generator 10. The decrease in the reference voltage Vref will in turn lead to a decrease in the output voltage HVout of the voltage regulator circuit 20.

[0064] It's understandable that HVout = Vop = Vbd + Veb. If Veb is larger, more SPADs will be triggered. Conversely, if Veb is smaller, fewer SPADs will be triggered, meaning a smaller Veb will reduce the trigger rate of the SPAD array.

[0065] Therefore, by taking advantage of the unstable loop characteristic of the reference voltage generator 10, when the output voltage HVout of the voltage regulator circuit 20 decreases, the triggering caused by ambient light will be reduced due to the decrease in Veb, which improves the performance of the solution of this application against ambient light and thus increases the probability of the tested object being detected.

[0066] Furthermore, it should be emphasized that when HVout drops to a certain level (below Vbd), since the number of SPAD triggers approaches 0, the voltage division of the first resistor R1 decreases, the supply voltage Vin of the reference voltage generator 10 returns to normal, and the reference voltage Vref also returns to normal, which will allow the circuit to enter the normal mode. That is, the solution of this application will not cause the entire circuit to stop working due to over-adjustment of HVout.

[0067] In one specific embodiment of the present invention, see [reference needed]. Figure 6 It may also include a first switch S1; the first switch S1 is connected in parallel with the first resistor R1; when the ambient light is weak, the first switch S1 is closed and the first resistor R1 is short-circuited; when the ambient light is strong, the first switch S1 is open.

[0068] This implementation takes into account that, in the previous implementation, by setting a first resistor R1, the value of the reference voltage and the value of the output voltage HVout can be reduced when the ambient light is strong, thereby reducing Veb, controlling the interference caused by high ambient light, and increasing the probability of the tested object being detected.

[0069] When the ambient light is weak, the first switch S1 can be closed, short-circuiting the first resistor R1, thus effectively ensuring the stability of the supply voltage Vin of the reference voltage generator 10, and consequently ensuring the stability of the reference voltage and output voltage HVout values. Of course, when the ambient light is strong, the first switch S1 needs to be opened to activate the first resistor R1.

[0070] Whether the first switch S1 is closed can be controlled by the user or automatically controlled by the corresponding controller based on the currently detected ambient light intensity, without affecting the implementation of the present invention.

[0071] Furthermore, in one specific embodiment of the present invention, considering that the resistance value of the first resistor R1 can be adjusted based on the ambient light level, i.e., the feedback intensity is controlled, the first resistor R1 can be specifically an adjustable resistor whose resistance value can be manually adjusted by the user. It is understood that the stronger the ambient light, the greater the resistance value of the first resistor R1 should be, thereby effectively reducing the value of the reference voltage and the output voltage HVout, thus reducing the triggering caused by ambient light. Conversely, the weaker the ambient light, the greater the resistance value of the first resistor R1 should be, ideally reducing it to 0, achieving the effect of closing the first switch S1 as described in the aforementioned embodiment.

[0072] In one specific embodiment of the present invention, see [reference needed]. Figure 7 It may also include: a second switch S2 connected in series with the first resistor R1, and n resistor branches connected in parallel with the first resistor R1, where n is a positive integer;

[0073] Each resistor branch includes one resistor and a switch connected in series with that resistor; by controlling the closing or opening of the switch in the resistor branch, the resistance value of the resistor connected in series between the first power supply and the power supply terminal of the reference voltage generator 10 can be adjusted.

[0074] In the aforementioned embodiment, the first resistor R1 is an adjustable resistor, thus enabling adjustment of its resistance value. However, this embodiment further considers that when the first resistor R1 is an adjustable resistor, the resistance value usually needs to be manually adjusted by the user, which increases the barrier to entry and hinders ease of use. Therefore, this embodiment includes a second switch S2 connected in series with the first resistor R1, and n parallel resistor branches. By adjusting the opening or closing of the switches in the resistor branches, the resistance value of the resistor connected in series between the first power supply and the power supply terminal of the reference voltage generator 10 can be effectively adjusted, achieving the effect of the first resistor R1 being an adjustable resistor as described in the previous embodiment.

[0075] Similarly, when adjusting the closing or opening of the switch in the resistor branch, the stronger the ambient light, the higher the resistance value of the resistor connected in series between the first power supply and the power supply terminal of the reference voltage generator 10 should be. Conversely, the weaker the ambient light, the lower the resistance value of the resistor connected in series between the first power supply and the power supply terminal of the reference voltage generator 10 should be.

[0076] Furthermore, in one specific embodiment of the present invention, the second switch S2 and the switches in the n resistor branches are all MOS transistors, and their gates are controlled by the output of a register.

[0077] In this embodiment, the second switch S2 and the switches in the n resistor branches described above can all be made of MOSFETs. MOSFETs have advantages such as high input impedance, low noise, good thermal stability, simple manufacturing process, and low on-state voltage.

[0078] Furthermore, since the resistance value of the resistor connected in series between the first power supply and the power supply terminal of the reference voltage generator 10 can be effectively controlled by controlling the second switch S2 and the switches in the n resistor branches, the gates of the second switch S2 and the switches in the n resistor branches can all be controlled by the output of the register. That is, the output of the register can be automatically adjusted according to the currently detected ambient light intensity, thereby automatically adjusting the resistance value of the resistor connected in series between the first power supply and the power supply terminal of the reference voltage generator 10, so as to achieve the best feedback strength.

[0079] See also Figure 8a and Figure 8b , Figure 8a This is a histogram comparison under low ambient light conditions in one specific embodiment of the present invention. Figure 8b This is a histogram comparison under high ambient light conditions in a specific embodiment of the present invention. It can be seen that in high-light environments, because the solution of this application can reduce the photosensitivity of the device, it controls the interference caused by high ambient light, significantly improving the probability of detecting the object under test. Furthermore, the reduction in the number of SPAD triggers also helps to reduce power consumption. Figure 8b In this case, actual tests showed that power consumption can be reduced to 80% of the original.

[0080] The technical solution provided by this invention utilizes the instability of the loop control of the reference voltage generator 10 to achieve adaptive control of HVout. Specifically, the reference voltage generator 10 generates a reference voltage Vref. The voltage regulator circuit 20 is connected to the output terminal of the reference voltage generator 10 and can maintain the stability of the output voltage HVout through its own feedback loop based on the reference voltage Vref. When the ambient light increases, the number of SPAD triggers in the subsequent stage increases, so the output current of the voltage regulator circuit 20 increases. Since this application sets a first resistor R1 between the first power supply and the power supply terminal of the reference voltage generator 10 and the power supply terminal of the voltage regulator circuit 20, when the output current of the voltage regulator circuit 20 increases, the voltage division of the first resistor R1 increases, which in turn reduces the supply voltage Vin of the reference voltage generator 10. Theoretically, a decrease in the supply voltage Vin of the reference voltage generator 10 should not affect the reference voltage Vref, meaning that the reference voltage Vref is generally considered a fixed value. However, this application utilizes the insufficient stability of the loop control of the reference voltage generator 10. Considering that a large change in the supply voltage Vin can cause the loop of the reference voltage generator 10 to become unstable, leading to a decrease in the output voltage of the reference voltage generator 10, i.e., a decrease in the reference voltage Vref output by the reference voltage generator 10. The decrease in the reference voltage Vref causes a decrease in the output voltage HVout of the voltage regulator circuit 20, thus reducing Veb. Furthermore, when HVout decreases to a certain level (below Vbd), the number of SPAD triggers approaches 0, reducing the voltage division of the first resistor R1, allowing the circuit to enter normal mode. Therefore, the solution in this application will not result in the entire circuit malfunctioning due to over-adjustment of HVout.

[0081] In summary, the solution presented in this application utilizes the insufficient stability of the 10-loop control of the reference voltage generator. By setting the first resistor R1, the value of the reference voltage and the output voltage HVout can be reduced when the ambient light is strong, thus achieving a reduction in Veb. Therefore, the solution presented in this application can achieve appropriate sensitivity values ​​for the circuit under different ambient light conditions, thereby helping to ensure the accuracy of distance measurement. Furthermore, the solution presented in this application avoids over-adjustment, and the fact that only the first resistor needs to be set also keeps the cost of the solution low.

[0082] Corresponding to the above embodiments of the high voltage generating circuit, this embodiment of the invention also provides a ranging device, which may include the high voltage generating circuit as in any of the above embodiments, and can be referred to in correspondence with the above description, and will not be repeated here.

[0083] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A high-voltage generation circuit, characterized in that, include: A reference voltage generator used to generate a reference voltage; A voltage regulator circuit connected to the output terminal of the reference voltage generator, used to maintain the output voltage (HVout) stable through its own feedback loop based on the reference voltage; The first terminal is connected to the first power supply, and the second terminal is connected to the power supply terminal of the reference voltage generator and the power supply terminal of the voltage regulator circuit respectively. The first resistor is used to reduce the value of the reference voltage and the value of the output voltage (HVout) through the first resistor. It also includes the first switch; The first switch is connected in parallel with the first resistor; When the ambient light is measured to be weak, the first switch closes and the first resistor is short-circuited. When the ambient light is detected to be strong, the first switch is turned off; The voltage regulator circuit includes: a first voltage divider circuit, a second voltage divider circuit, a comparator, and a charge pump; The positive input terminal of the comparator is connected to the output terminal of the reference voltage generator, the negative input terminal of the comparator is connected to the common terminal of the first voltage divider circuit and the second voltage divider circuit, and the output terminal of the comparator is connected to the input terminal of the charge pump. The power supply terminal of the charge pump serves as the power supply terminal of the voltage regulator circuit, and the output terminal of the charge pump serves as the output terminal of the voltage regulator circuit. The first voltage divider circuit and the second voltage divider circuit are connected in series between the output terminal of the voltage regulator circuit and ground.

2. The high-voltage generation circuit according to claim 1, characterized in that, The first voltage divider circuit includes a second resistor, and the second voltage divider circuit includes a third resistor; The second resistor and the third resistor are connected in series between the output terminal of the voltage regulator circuit and ground.

3. The high-voltage generation circuit according to claim 1, characterized in that, The first resistor is an adjustable resistor.

4. The high-voltage generation circuit according to claim 1, characterized in that, The output voltage (HVout) is connected to the cathodes of multiple SPADs, and the anode of each SPAD is grounded through a MOS switch connected in series.

5. The high-voltage generation circuit according to any one of claims 1 to 4, characterized in that, Also includes: A second switch connected in series with the first resistor, and n resistor branches connected in parallel with the first resistor, where n is a positive integer; Each of the resistor branches includes one resistor and a switch connected in series with the resistor; by controlling the switch of the resistor branch to close or open, the resistance value of the resistor connected in series between the first power supply and the power supply terminal of the reference voltage generator can be adjusted.

6. The high-voltage generation circuit according to claim 5, characterized in that, The second switch and the switches in the n resistor branches are all MOSFET switches, and their gates are controlled by the output of the register.

7. A ranging device, characterized in that, Includes the high-voltage generation circuit as described in any one of claims 1 to 6.

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