阅读说明：本技术 一种具有复位控制的窗口信号产生和阈值计数电路 (Window signal generation and threshold counting circuit with reset control ) 是由 刘马良 楚泽坤 胡进 刘秉政 朱樟明 杨银堂 于 2019-10-24 设计创作，主要内容包括：本发明涉及一种具有复位控制的窗口信号产生和阈值计数电路,包括窗口产生模块、阈值计数模块和复位控制模块,窗口产生模块的输入端和阈值计数模块的输入端接收光子信号,阈值计数模块的输出端连接窗口产生模块的控制信号输入端,窗口产生模块的输出端连接复位控制模块的输入端,复位控制模块输出端分别连接窗口产生模块的复位端和阈值计数模块的复位端；窗口产生模块根据光子信号和控制信号输出STOP信号；阈值计数模块对光子信号进行计数,并与设定的阈值比较判断得到控制信号；复位控制模块根据STOP信号产生复位信号,使电路进行复位操作。本发明的电路,能够有效的减少由于背景光和暗计数产生的误触发信号。(The invention relates to a window signal generation and threshold value counting circuit with reset control, which comprises a window generation module, a threshold value counting module and a reset control module, wherein the input end of the window generation module and the input end of the threshold value counting module receive photon signals, the output end of the threshold value counting module is connected with the control signal input end of the window generation module, the output end of the window generation module is connected with the input end of the reset control module, and the output end of the reset control module is respectively connected with the reset end of the window generation module and the reset end of the threshold value counting module; the window generation module outputs a STOP signal according to the photon signal and the control signal; the threshold counting module counts the photon signals and compares the photon signals with a set threshold to obtain a control signal; the reset control module generates a reset signal according to the STOP signal to enable the circuit to carry out reset operation. The circuit of the invention can effectively reduce false triggering signals generated by background light and dark counts.)

1. A window signal generation and threshold counting circuit with reset control is characterized by comprising a window generation module (1), a threshold counting module (2) and a reset control module (3),

the input end of the window generation module (1) and the input end of the threshold counting module (2) receive a photon signal (IN), the output end of the threshold counting module (2) is connected with the control signal input end of the window generation module (1), the output end of the window generation module (1) is connected with the input end of the reset control module (3), and the output end of the reset control module (3) is respectively connected with the reset end of the window generation module (1) and the reset end of the threshold counting module (2);

the window generation module (1) is used for outputting a STOP signal according to the photon signal (IN) and a control Signal (SW);

the threshold counting module (2) is used for counting the photon signals (IN) and comparing and judging the photon signals (IN) with a set threshold to obtain the control Signals (SW);

the reset control module (3) generates a reset signal according to the STOP signal, and the window generation module (1) and the threshold counting module (2) carry out reset operation according to the reset signal.

2. Window signal generation with reset control and threshold counting circuit according to claim 1, characterized in that the window generation block (1) comprises a first D flip-flop (D1), a delay unit (101), a second D flip-flop (D2), a Transmission Gate (TG) and a first inverter (I)₁) Wherein, in the step (A),

the input end of the first D flip-flop (D1) is connected with a voltage end (VDD), a clock end receives the photon signal (IN), and the output end is connected with the input end of the delay unit (101);

the delay unit (101) is used for adjusting the voltage of an input signal to control the delay between the rising edge of the output signal and the rising edge of the input signal;

the input end of the second D flip-flop (D2) is connected with the voltage end (VDD), the clock is connected with the output end of the delay unit (101), and the output end of the second D flip-flop is connected with the input end of the Transmission Gate (TG);

the Transmission Gate (TG) is used for being opened or closed according to the received control Signal (SW), and the output end of the Transmission Gate (TG) is connected with the input end of the reset control module (3);

the first inverter (I)₁) Is connected with the output end of the second D flip-flop (D2), and the output ends are respectively connected with the reset end of the first D flip-flop (D1) and the reset end of the second D flip-flop (D2).

3. Window signal generation with reset control and threshold count circuit according to claim 2, characterized in that the threshold count module (2) comprises a counter unit (201), a threshold logic generation unit (202), a selection circuit unit (203) and a third D flip-flop (D3) connected in sequence, wherein,

the counter unit (201) is used for counting the received photon signals (IN) and transmitting the counting result to the threshold value logic generation unit (202);

the threshold logic generation unit (202) is used for comparing and judging the counting result with a set threshold and outputting a judgment result;

the selection circuit unit (203) is used for outputting a selection result according to the judgment result and the received selection signal;

the input end of the third D trigger (D3) is connected with the voltage end (VDD), the clock end is connected with the output end of the selection circuit unit (203), and the output end is connected with the control signal input end of the Transmission Gate (TG).

4. Window signal generation and threshold counting circuit with reset control according to claim 3, characterized in that the reset control module (3) comprises a fourth D flip-flop (D4), a second inverter (I)₂) A third inverter (I)₃) NMOS tube (N)₁) AND gate (U)₁) A first NOR gate (U)₂) And a second NOR gate (U)₃) Wherein, in the step (A),

the input end of the fourth D trigger (D4) is connected with the voltage end (VDD), the clock end is connected with the output end of the Transmission Gate (TG), and the output end is connected with the AND gate (U)₁) Is connected to said first nor gate (U) and an inverted output is connected to said first nor gate (U)₂) A first input terminal of;

the second inverter (I)₂) Respectively, and output terminals thereof are connected to the reset terminal of the third D flip-flop (D3), the reset terminal of the fourth D flip-flop (D4) and the third inverter (I)₃) An input terminal of (1);

the NMOS tube (N)₁) Is connected to the third inverter (I)₃) The drain is connected with the output end of the Transmission Gate (TG), and the source is connected with the ground end (GND);

the AND gate (U)₁) Receives the photon signal (IN), and has output terminals respectively connected to the clock terminal of the first D flip-flop (D1) and the clock terminal of the counter unit (201);

the first NOR gate (U)₂) Is connected to said first inverter (I)₁) Is connected to the second nor gate (U)₃) A first input terminal of;

the second NOR gate (U)₃) Receives the START signal and has an output connected to a reset terminal of the counter unit (201).

5. Window signal generation and threshold counting circuit with reset control according to claim 3, characterized in that the counter unit (201) is a three-bit shift counter.

6. The window signal generation and threshold count circuit with reset control of claim 3, wherein the threshold of said threshold logic generation unit (202) is set to 3.

7. The window signal generation and threshold count circuit with reset control of claim 3, wherein said selection circuit unit (203) is a one-out-of-four data selector.

Technical Field

The invention belongs to the technical field of integrated circuits, and particularly relates to a window signal generation and threshold counting circuit with reset control.

Background

Single photon detection is a new detection technology developed in recent years, can be applied to the fields of biochip detection, medical diagnosis, nondestructive substance analysis, astronomical observation, national defense and military, spectral measurement, quantum electronics and the like, and plays an important role therein, and the important engineering value of single photon detectors in some new high-tech fields is more and more fully embodied.

A Single Photon Avalanche Diode (SPAD) and a Time To Digital Converter (TDC) are important components of a laser radar (LIDAR), and are essential in the technical field of LIDAR detection. The TDC circuit has the advantage of high distance resolution, can convert time interval information into digital quantity for output, and realizes the measurement of high-precision time intervals. The SPAD has high gain and high signal-to-noise ratio, single photon can trigger avalanche to generate avalanche current, and extremely large photo-generated current gain can be obtained. Single photon detectors based on semiconductor Avalanche Photodiodes (APDs) are usually operated constantly at bias voltages lower than the reverse breakdown voltage due to the influence of dark (background) noise, so-called linear mode avalanche photodiodes, which have only a small avalanche gain and no single photon detection capability. The avalanche photodiode which works under the over-bias condition that the bias voltage is higher than the reverse breakdown voltage, namely the avalanche photodiode in the Geiger mode, the over-bias condition enables the avalanche multiplication region to form a strong electric field, when a carrier generated by single photon incidence enters the avalanche multiplication region, the avalanche multiplication (gain >106) can be triggered with a certain probability, the single photon current is increased to a large current (milliampere magnitude) which is easy to detect in a picosecond time magnitude, the avalanche photodiode has single photon detection performance, and the avalanche photodiode capable of realizing single photon detection in the working mode is called as a Single Photon Avalanche Diode (SPAD).

Because semiconductor avalanche breakdown has a self-sustaining behavior, the working performance and reliability of SPAD will be damaged when it is in avalanche state for a long time, a dynamic bias and a fast quenching circuit are needed, so that after SPAD avalanche occurs, the avalanche current can be quenched quickly and the SPAD can be restored to a waiting detection state, the control process is complicated, and the defect of dark count is caused. Therefore, the design of the window signal generation and threshold counting circuit with the reset control, which reduces the dark counting defect, has important significance and application prospect.

Disclosure of Invention

To solve the above problems in the prior art, the present invention provides a window signal generation and threshold counting module with reset control. The technical problem to be solved by the invention is realized by the following technical scheme:

the invention provides a window signal generation and threshold value counting circuit with reset control, which comprises a window generation module, a threshold value counting module and a reset control module, wherein,

the input end of the window generation module and the input end of the threshold counting module receive photon signals, the output end of the threshold counting module is connected with the control signal input end of the window generation module, the output end of the window generation module is connected with the input end of the reset control module, and the output end of the reset control module is respectively connected with the reset end of the window generation module and the reset end of the threshold counting module;

the window generation module is used for outputting a STOP signal according to the photon signal and the control signal;

the threshold counting module is used for counting the photon signals and comparing and judging the photon signals with a set threshold to obtain the control signals;

the reset control module generates a reset signal according to the STOP signal, and the window generation module and the threshold counting module perform reset operation according to the reset signal.

In one embodiment of the present invention, the window generating module includes a first D flip-flop, a delay unit, a second D flip-flop, a transmission gate, and a first inverter, wherein,

the input end of the first D trigger is connected with a voltage end, the clock end receives the photon signal, and the output end is connected with the input end of the delay unit;

the delay unit is used for adjusting the voltage of an input signal to control the delay between the rising edge of an output signal of the delay unit and the rising edge of the input signal;

the input end of the second D trigger is connected with the voltage end, the clock is connected with the output end of the delay unit, and the output end of the second D trigger is connected with the input end of the transmission gate;

the transmission gate is used for being opened or closed according to the received control signal, and the output end of the transmission gate is connected with the input end of the reset control module;

the input end of the first phase inverter is connected with the output end of the second D trigger, and the output end of the first phase inverter is respectively connected with the reset end of the first D trigger and the reset end of the second D trigger.

In one embodiment of the present invention, the threshold counting module includes a counter unit, a threshold logic generation unit, a selection circuit unit, and a third D flip-flop, which are connected in sequence, wherein,

the counter unit is used for counting the received photon signals and transmitting counting results to the threshold logic generation unit;

the threshold logic generation unit is used for comparing and judging the counting result with a set threshold and outputting a judgment result;

the selection circuit unit is used for outputting a selection result according to the judgment result and the received selection signal;

the input end of the third D trigger is connected with the voltage end, the clock end is connected with the output end of the selection circuit unit, and the output end of the third D trigger is connected with the control signal input end of the transmission gate.

In one embodiment of the present invention, the reset control module includes a fourth D flip-flop, a second inverter, a third inverter, an NMOS transistor, an and gate, a first nor gate, and a second nor gate, wherein,

the input end of the fourth D trigger is connected with the voltage end, the clock end is connected with the output end of the transmission gate, the output end of the fourth D trigger is connected with the first input end of the AND gate, and the reverse output end of the fourth D trigger is connected with the first input end of the first NOR gate;

the input end of the second inverter receives a START signal, and the output end of the second inverter is respectively connected with the reset end of the third D flip-flop, the reset end of the fourth D flip-flop and the input end of the third inverter;

the grid electrode of the NMOS tube is connected with the output end of the third phase inverter, the drain electrode of the NMOS tube is connected with the output end of the transmission gate, and the source electrode of the NMOS tube is connected with the grounding end;

a second input end of the AND gate receives the photon signal, and output ends of the AND gate are respectively connected with a clock end of the first D trigger and a clock end of the counter unit;

the second input end of the first NOR gate is connected with the output end of the first inverter, and the output end of the first NOR gate is connected with the first input end of the second NOR gate;

and a second input end of the second NOR gate receives the START signal, and an output end of the second NOR gate is connected with a reset end of the counter unit.

In one embodiment of the invention, the counter unit is a three-bit shift counter.

In one embodiment of the present invention, the threshold value of the threshold value logic generation unit is set to 3.

In one embodiment of the present invention, the selection circuit unit is a one-out-of-four data selector.

Compared with the prior art, the invention has the beneficial effects that:

the window signal generation and threshold counting circuit with reset control is provided with a window generation module and a threshold counting module, wherein the threshold counting module generates a corresponding threshold through counting photon signals, if the number of the photon signals reaches the set threshold, the window generation module outputs a STOP signal, and because the number of photons of a laser echo signal in a very short time is far more than that of photons of the surrounding environment, the laser echo signal is determined by the short-time counting method, and false triggering signals generated by background light and dark counting can be effectively reduced.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are described in detail with reference to the accompanying drawings.

Drawings

FIG. 1 is a block diagram of a window signal generation and threshold count circuit with reset control according to an embodiment of the present invention;

FIG. 2 is a detailed circuit diagram of a window signal generation and threshold counting circuit with reset control according to an embodiment of the present invention;

fig. 3 is a circuit diagram of a threshold logic generating unit according to an embodiment of the present invention;

fig. 4 is a timing diagram according to an embodiment of the invention.

Detailed Description

To further illustrate the technical means and effects of the present invention for achieving the predetermined objects, a window signal generating and threshold counting circuit with reset control according to the present invention is described in detail below with reference to the accompanying drawings and the detailed description.

The foregoing and other technical matters, features and effects of the present invention will be apparent from the following detailed description of the embodiments, which is to be read in connection with the accompanying drawings. The technical means and effects of the present invention adopted to achieve the predetermined purpose can be more deeply and specifically understood through the description of the specific embodiments, however, the attached drawings are provided for reference and description only and are not used for limiting the technical scheme of the present invention.