阅读说明：本技术 一种适用于辐射检测前端读出电路的时间甄别器 (Time discriminator suitable for radiation detection front-end reading circuit ) 是由 王巍 张定冬 赵汝法 熊德宇 刘博文 张珊 袁军 于 2020-11-26 设计创作，主要内容包括：本发明请求保护一种适用于辐射检测前端读出电路的时间甄别器,属于微电子技术领域,包括时间甄别电路和脉冲产生电路。其中,时间甄别电路的输入信号来自于辐射检测前端读出电路的输出信号,脉冲产生电路的输入端与时间甄别电路的输出端相连,脉冲产生器的输出端为输出的时间标记信号。本发明包括时间甄别电路和脉冲产生电路,所述时间甄别器用于判断前端读出电路的输出信号是否超过设定的阈值,且阈值可以通过外部数字信号控制,脉冲产生电路用于将时间甄电路产生的突变信号转变为一个脉冲信号,且脉冲宽度可调,从而实现了对辐射检测读出电路信号的精确标记。(The invention discloses a time discriminator applicable to a radiation detection front-end reading circuit, belonging to the technical field of microelectronics. The input signal of the time discrimination circuit is from the output signal of the radiation detection front-end reading circuit, the input end of the pulse generation circuit is connected with the output end of the time discrimination circuit, and the output end of the pulse generator is the output time marking signal. The device comprises a time discriminator circuit and a pulse generating circuit, wherein the time discriminator circuit is used for judging whether an output signal of a front-end reading circuit exceeds a set threshold value, the threshold value can be controlled by an external digital signal, the pulse generating circuit is used for converting a mutation signal generated by the time discriminator circuit into a pulse signal, and the pulse width is adjustable, so that the accurate marking of a radiation detection reading circuit signal is realized.)

1. A time discriminator suitable for use in a radiation detection front-end readout circuit, comprising: a time discrimination circuit and a pulse generation circuit; the input port of the time discrimination circuit is connected with the output end of the front-end reading circuit, the output port of the time discrimination circuit is connected with the input end of the pulse generation circuit, the output end of the pulse generation circuit directly outputs signals, the time discrimination circuit is used for judging whether the output signals of the radiation detection front-end reading circuit exceed a set threshold value, and the time discrimination circuits are NM1, NM2 and NM3 and PM1, PM2, PM3 realize the comparison of input voltage and threshold value, change the equivalent size of this NMOS pipe through controlling the conduction of NM4, NM6, NM8, NM10, reach the function that the threshold value is adjustable, the pulse generating circuit outputs the pulse signal that can be used for digital processing after receiving the discrimination result of the time discriminator circuit, form three buffers through PM11, NM11, PM12, NM12, PM13, NM13, improve the driving ability of the input signal DIN, and will exceed V drive the ability of V_THHThe falling edge signals of the input signal TIN are converted into rising edge signals, PM16, NM16, PM17, NM17, PM18 and NM18 form three delay units, the falling edge generated by the buffer is delayed by T, then the rising edge is converted into the falling edge, and PM14, PM15, NM14 and NM15 form a NAND gate, so that one falling edge of the input signal TIN is converted into a negative pulse signal TOUT, and the function of pulse output is achieved.

2. The time discriminator suitable for the radiation detection front end readout circuit according to claim 1, wherein the time discriminator comprises ten PMOS transistors, PM1, PM2, PM3, PM4, PM5, PM6, PM7, PM8, PM9, PM10, ten NMOS transistors, NM1, NM2, NM3, NM4, NM5, NM6, NM7, NM8, NM9, NM10, the source of PM1, the source of PM5, the source of PM7, the source of PM9, the drain of PM3 are connected to a power supply VDD; the source of NM1, the source of NM5, the source of NM7, the source of NM9 and the drain of NM3 are connected with a ground line GND; the drain of PM1 is connected to the source of PM4, the drain of PM5 is connected to the source of PM6, the drain of PM7 is connected to the source of PM8, and the drain of PM9 is connected to the source of PM 10; the drain of NM1 is connected with the source of NM4, the drain of NM5 is connected with the source of NM6, the drain of NM7 is connected with the source of NM8, and the drain of NM9 is connected with the source of NM 10; the drains of PM4, PM6, PM8 and PM10 are connected with the source of PM 3; the drains of NM4, NM6, NM8 and NM10 are connected with the source of NM 3; the gates of the PM1, PM2, PM5, PM7 and PM9 and the gates of the NM1, NM2, NM5, NM7 and NM9 are connected together to be used as an input terminal DIN of the time screening circuit; the drains of the PM2 and the NM2, and the gates of the PM3 and the NM3 are connected together to be used as an output end DOUT of the time discrimination circuit; the gates of the PM4, PM6, PM8 and PM10 are respectively connected with the outsideControl signal V_SPL1、V_SPL2、V_SPL3、V_SPL4; the gates of NM4, NM6, NM8 and NM10 are respectively connected with an external control signal V_SPH1、V_SPH2、V_SPH3、V_SPH4。

3. The time discriminator for radiation detection front-end readout circuits according to claim 2, wherein the V in the time discriminator circuit_SPL1、V_SPL2、V_SPL3、V_SPL4, PM4, PM6, PM8 and PM10 are controlled to be conducted or not, PM4, PM6, PM8 and PM10 are used as MOS switches to control whether PM1, PM5, PM7 and PM9 are connected into a circuit or not, the equivalent width-length ratio of a PMOS tube is changed, and the threshold V of a discriminator is changed_THLIn which V is_THLThe discriminator threshold is the threshold of the discriminator when the input signal DIN goes from low to high. V_SPH1、V_SPH2、V_SPH3、V_SPH4, NM4, NM6, NM8, NM10 are controlled to be conducted or not, NM4, NM6, NM8, NM10 are used as MOS switches to control whether NM1, NM5, NM7, NM9 are connected into a circuit or not, so that the equivalent width-length ratio of an NMOS tube is changed, and the threshold value V of the discriminator is changed_THHIn which V is_THHIs the threshold of the discriminator when the input signal DIN changes from high to low. External digital signal V_SPHAnd V_SPLControl V_THHAnd V_THLThe threshold value is adjustable when the input signal DIN is larger than V_THHWhen the output of the time discrimination circuit is low level 0, when the input signal DIN is less than V_THLIn time, the output of the time discrimination circuit is high level 1, realizing the hysteresis effect.

4. The time discriminator for radiation detection front-end readout circuits according to claim 1, wherein the V in the time discriminator circuit_THH、V_THLCan realize adjustment by adjusting the equivalent width-length ratio of the MOS tube when V is_SPH1＝1、V_SPH2＝0、V_SPH3＝0、V_SPHWhen 4 is equal to 0, according toTo obtain In the formula of_nFor electron mobility, C_OXGate capacitance, W is the width of the corresponding MOS transistor, L is the length of the corresponding MOS transistor, V_THHFor the threshold voltage at the transition of the input from low to high, V_THNBy properly selecting the size of NM1, NM3 to correspond to the threshold voltage of NMOS transistor, the desired V can be set_SPHThe time discrimination circuit changes the equivalent size of the NMOS tube by controlling the conduction of NM4, NM6, NM8 and NM10, the equivalent size is the sum of the width-length ratios of the conducted NM1, NM5, NM7 and NM9, and similarly, V is_THLCan also be adjusted by the width-to-length ratio of PM1 to PM3, with the relationship betweenWherein V_THPThe time discriminator circuit is used for changing the equivalent size of the DP of the PMOS tube by controlling the conduction of PM4, PM6, PM8 and PM10, wherein the equivalent size is the sum of the width-to-length ratios of the conduction PMOSs in PM1, PM5, PM7 and PM 9. And further can control V in the time discrimination circuit through a digital signal_THHAnd V_THLAnd is convenient to be applied to various occasions.

5. The time discriminator for radiation detection front-end readout circuits according to claim 1, wherein said pulse generating circuit comprises eight PMOS transistors, respectively: PM11, PM12, PM13, PM14, PM15, PM16, PM17, PM 18; eight NMOS, respectively: NM11, NM12, NM13, NM14, NM15, NM16, NM17, NM 18; sources of PM11, PM12, PM13, PM14, PM15, PM16, PM17 and PM18 are connected with a power supply VDD; the sources of NM11, NM12, NM13, NM14, NM15, NM16, NM17 and NM18 are all connected with the ground line GND; the drains of the PM11 and the NM11 are connected with the gates of the PM12 and the NM 12; the drains of the PM12 and the NM12 are connected with the gates of the PM13 and the NM 13; the drains of the PM13 and NM13 are connected with the gates of the PM14, NM15, PM16 and NM 16; the drains of the PM16 and the NM16 are connected with the gates of the PM17 and the NM 17; the drains of the PM17 and the NM17 are connected with the gates of the PM18 and the NM 18; the drains of the PM18 and NM18 are connected with the gates of the PM15 and NM14 to be used as the output TOUT of the pulse generating circuit; the drains of the PM15 and PM14 are connected with the source of the NM 14; the gates of PM11 and NM11 are connected as inputs to a pulse generation circuit.

6. The time discriminator of claim 5, wherein the pulse generator circuit includes three buffers, PM11, NM11, PM12, NM12, PM13, NM13, to increase the driving capability of the input signal DIN, and to exceed V_THHThe falling edge signals of the input signal TIN are converted into rising edge signals, PM16, NM16, PM17, NM17, PM18 and NM18 form three delay units, the falling edge generated by the buffer is delayed by T, then the rising edge is converted into the falling edge, PM14, PM15, NM14 and NM15 form a NAND gate, and therefore one falling edge of the input signal TIN is converted into a negative pulse signal TOUT, and the pulse width of the negative pulse signal is T so that the negative pulse signal can be processed by a back-end digital circuit.

Technical Field

The invention belongs to the technical field of microelectronics, particularly relates to a time discriminator, and particularly relates to a time discriminator suitable for a radiation detection front-end reading circuit.

Background

The radiation detection system has wide application in the fields of space detection, medical imaging, quality inspection safety inspection, homeland security and the like. The radiation detection system mainly comprises a front-end reading circuit, an amplifier, a shaping filter and the like, wherein the output of a shaper is a quasi-Gaussian waveform. In some application scenarios with higher requirements on speed, time accuracy and power consumption, the time discriminator has a great influence on the final detection accuracy.

A conventional readout circuit and a conventional time discriminator are shown in fig. 1, and a quasi-gaussian waveform is output after radiation is detected by a detector and processed by a front-end circuit of an amplifier and a shaping filter. The Gaussian waveform is input to a time discriminator and is compared with a reference signal V_REFThe comparison is performed and then a rising edge or falling edge signal is output for processing by a following digital circuit. The traditional time discriminator has the following defects that the reference voltage is generated by an independent DAC (digital-analog converter), the circuit is large, and the power consumption is high. The other is that the conventional comparator is usually composed of an open-loop operational amplifier, and has no hysteresis effect, which may cause misjudgment when the threshold is too low, and generate an error signal.

Disclosure of Invention

The present invention is directed to solving the above problems of the prior art. A time discriminator suitable for radiation detection front-end readout circuits is presented. The technical scheme of the invention is as follows:

a time discriminator suitable for use in a radiation detection front-end readout circuit, comprising: a time discrimination circuit and a pulse generation circuit; the input port of the time discrimination circuit is connected with the output end of the front-end reading circuit, and the output port of the time discrimination circuit is connected with the input of the pulse generating circuitThe time discrimination circuit is used for discriminating whether the output signal of the radiation detection front-end reading circuit exceeds a set threshold value, the time discrimination circuit is NM1, NM2, NM3, PM1, PM2 and PM3 to realize comparison of input voltage and the threshold value, the equivalent size of the NMOS tube is changed by controlling the conduction of NM4, NM6, NM8 and NM10 to achieve the function of adjusting the threshold value, the pulse generation circuit outputs a pulse signal which can be used for digital processing after receiving the discrimination result of the time discrimination circuit, and PM11, NM11, PM12, NM12, PM13 and NM13 form three buffers to improve the driving capability of an input signal DIN and enable the output signal to exceed V_THHThe falling edge signals of the input signal TIN are converted into rising edge signals, PM16, NM16, PM17, NM17, PM18 and NM18 form three delay units, the falling edge generated by the buffer is delayed by T, then the rising edge is converted into the falling edge, and PM14, PM15, NM14 and NM15 form a NAND gate, so that one falling edge of the input signal TIN is converted into a negative pulse signal TOUT, and the function of pulse output is achieved.

Further, the time screening circuit comprises ten PMOS transistors, PM1, PM2, PM3, PM4, PM5, PM6, PM7, PM8, PM9 and PM10, ten NMOS transistors, NM1, NM2, NM3, NM4, NM5, NM6, NM7, NM8, NM9 and NM10, wherein a source of the PM1, a source of the PM5, a source of the PM7, a source of the PM9 and a drain of the PM3 are connected to a power supply VDD; the source of NM1, the source of NM5, the source of NM7, the source of NM9 and the drain of NM3 are connected with a ground line GND; the drain of PM1 is connected to the source of PM4, the drain of PM5 is connected to the source of PM6, the drain of PM7 is connected to the source of PM8, and the drain of PM9 is connected to the source of PM 10; the drain of NM1 is connected with the source of NM4, the drain of NM5 is connected with the source of NM6, the drain of NM7 is connected with the source of NM8, and the drain of NM9 is connected with the source of NM 10; the drains of PM4, PM6, PM8 and PM10 are connected with the source of PM 3; the drains of NM4, NM6, NM8 and NM10 are connected with the source of NM 3; the gates of the PM1, PM2, PM5, PM7 and PM9 and the gates of the NM1, NM2, NM5, NM7 and NM9 are connected together to be used as an input terminal DIN of the time screening circuit; the drains of the PM2 and the NM2, and the gates of the PM3 and the NM3 are connected together to be used as an output end DOUT of the time discrimination circuit; the PM4. The gates of the PM6, PM8 and PM10 are respectively connected with an external control signal V_SPL1、V_SPL2、V_SPL3、V_SPL4; the gates of NM4, NM6, NM8 and NM10 are respectively connected with an external control signal V_SPH1、V_SPH2、V_SPH3、V_SPH4。

Further, V in the time discrimination circuit_SPL1、V_SPL2、V_SPL3、V_SPL4, PM4, PM6, PM8 and PM10 are controlled to be conducted or not, PM4, PM6, PM8 and PM10 are used as MOS switches to control whether PM1, PM5, PM7 and PM9 are connected into a circuit or not, the equivalent width-length ratio of a PMOS tube is changed, and the threshold V of a discriminator is changed_THLIn which V is_THLThe discriminator threshold is the threshold of the discriminator when the input signal DIN goes from low to high. V_SPH1、V_SPH2、V_SPH3、V_SPH4, NM4, NM6, NM8, NM10 are controlled to be conducted or not, NM4, NM6, NM8, NM10 are used as MOS switches to control whether NM1, NM5, NM7, NM9 are connected into a circuit or not, so that the equivalent width-length ratio of an NMOS tube is changed, and the threshold value V of the discriminator is changed_THHIn which V is_THHIs the threshold of the discriminator when the input signal DIN changes from high to low. External digital signal V_SPHAnd V_SPLControl V_THHAnd V_THLThe threshold value is adjustable when the input signal DIN is larger than V_THHWhen the output of the time discrimination circuit is low level 0, when the input signal DIN is less than V_THLIn time, the output of the time discrimination circuit is high level 1, realizing the hysteresis effect.

Further, V in the time discrimination circuit_THH、V_THLCan realize adjustment by adjusting the equivalent width-length ratio of the MOS tube when V is_SPH1＝1、V_SPH2＝0、V_SPH3＝0、V_SPHWhen 4 is equal to 0, according toTo obtain In the formula of_nFor electron mobility, C_OXGate capacitance, W is the width of the corresponding MOS transistor, L is the length of the corresponding MOS transistor, V_THHFor the threshold voltage at the transition of the input from low to high, V_THNBy properly selecting the size of NM1, NM3 to correspond to the threshold voltage of NMOS transistor, the desired V can be set_SPHThe time discrimination circuit changes the equivalent size of the NMOS tube by controlling the conduction of NM4, NM6, NM8 and NM10, the equivalent size is the sum of the width-length ratios of the conducted NM1, NM5, NM7 and NM9, and similarly, V is_THLCan also be adjusted by the width-to-length ratio of PM1 to PM3, with the relationship betweenWherein V_THPThe time discriminator circuit is used for changing the equivalent size of the DP of the PMOS tube by controlling the conduction of PM4, PM6, PM8 and PM10, wherein the equivalent size is the sum of the width-to-length ratios of the conduction PMOSs in PM1, PM5, PM7 and PM 9. And further can control V in the time discrimination circuit through a digital signal_THHAnd V_THLAnd is convenient to be applied to various occasions.

Further, the pulse generating circuit comprises eight PMOS, which are respectively: PM11, PM12, PM13, PM14, PM15, PM16, PM17, PM 18; eight NMOS, respectively: NM11, NM12, NM13, NM14, NM15, NM16, NM17, NM 18; sources of PM11, PM12, PM13, PM14, PM15, PM16, PM17 and PM18 are connected with a power supply VDD; the sources of NM11, NM12, NM13, NM14, NM15, NM16, NM17 and NM18 are all connected with the ground line GND; the drains of the PM11 and the NM11 are connected with the gates of the PM12 and the NM 12; the drains of the PM12 and the NM12 are connected with the gates of the PM13 and the NM 13; the drains of the PM13 and NM13 are connected with the gates of the PM14, NM15, PM16 and NM 16; the drains of the PM16 and the NM16 are connected with the gates of the PM17 and the NM 17; the drains of the PM17 and the NM17 are connected with the gates of the PM18 and the NM 18; the drains of the PM18 and NM18 are connected with the gates of the PM15 and NM14 to be used as the output TOUT of the pulse generating circuit; the drains of the PM15 and PM14 are connected with the source of the NM 14; the gates of PM11 and NM11 are connected as inputs to a pulse generation circuit.

Further, the pulse generating circuit comprises three buffers consisting of PM11, NM11, PM12, NM12, PM13 and NM13, so that the driving capability of the input signal DIN is improved, and the input signal DIN exceeds V_THHThe falling edge signals of the input signal TIN are converted into rising edge signals, PM16, NM16, PM17, NM17, PM18 and NM18 form three delay units, the falling edge generated by the buffer is delayed by T, then the rising edge is converted into the falling edge, PM14, PM15, NM14 and NM15 form a NAND gate, and therefore one falling edge of the input signal TIN is converted into a negative pulse signal TOUT, and the pulse width of the negative pulse signal is T so that the negative pulse signal can be processed by a back-end digital circuit.

The invention has the following advantages and beneficial effects:

1. the time discriminator is used for discriminating the signal output by the radiation detection front-end reading circuit and rapidly generating a falling edge or rising edge signal after the signal exceeds a set threshold value. The whole time discriminator has a simple structure, the power consumption is obviously reduced compared with the traditional circuit, and the threshold can be controlled by external digital signals under the condition that other digital-to-analog conversion circuits are not needed, so that the function of adjusting the threshold can be realized. And can be adjusted by adjusting V_THHAnd V_THLThe relation realizes the hysteresis effect, ensures that the edge signal generated under the condition of low threshold value can not be interfered by noise, and is stable and reliable.

2. The invention adds a pulse generating circuit at the output end of the time discrimination circuit, can detect the falling edge or rising edge signal output by the time discrimination circuit and generate a pulse signal available for a back-end digital circuit. The combination of the delay unit and the NAND gate realizes accurate judgment of the falling edge. Compared with the traditional time discriminator without the pulse generating circuit, the time discriminator with the pulse generating circuit does not need to discriminate the rising edge or the falling edge in the digital processing stage, thereby reducing the difficulty of digital processing. The pulse width can be controlled by the number of delay stages in the time delay unit or the width-length ratio of MOS (metal oxide semiconductor) tubes forming the time delay unit, so that the application range of the time discriminator circuit is widened, and the time discriminator circuit is flexible and adjustable. The method can be widely applied to the field of radiation detection.

Drawings

Fig. 1 is a schematic block diagram of a conventional time discriminator.

Fig. 2 is a schematic block diagram of the time discriminator of the present invention.

Fig. 3 is a specific circuit diagram of the time screening circuit according to the present invention.

FIG. 4 is a specific circuit diagram of the pulse generating circuit of the present invention.

Fig. 5 is a diagram of transient simulation results of the time screening circuit of the present invention.

FIG. 6 is a diagram showing a transient simulation of the pulse generating circuit according to the present invention.

Figure 7 is a transient simulation of the entire time discriminator in combination with the radiation detection front-end readout circuit of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described in detail and clearly with reference to the accompanying drawings. The described embodiments are only some of the embodiments of the present invention.

The technical scheme for solving the technical problems is as follows:

according to the embodiment of the application, the read-out signals at the front end of the detector are distinguished through the innovative time discrimination circuit, and the time marking signals are rapidly generated when the time marking signals pass through the threshold. In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and specific examples.

Examples

As shown in fig. 2, a time discriminator suitable for use in a radiation detection front-end readout circuit, includes: a time discrimination circuit and a pulse generation circuit. The input of the time discrimination circuit is connected with the output of the front end of the radiation detector, the output of the time discrimination circuit is connected with the input of the pulse generation circuit, and the threshold value adjusting port is connected with the time discrimination circuit.

As shown in fig. 3, the time screening circuit includes ten PMOS transistors PM1, PM2, PM3, PM4, PM5, PM6, PM7, PM8, PM9, and PM10, respectively. Ten NMOS transistors are NM1, NM2, NM3, NM4, and,NM5, NM6, NM7, NM8, NM9, NM 10. The source electrode of the PM1, the source electrode of the PM5, the source electrode of the PM7, the source electrode of the PM9 and the drain electrode of the PM3 are connected with a power supply VDD. The source of NM1, the source of NM5, the source of NM7, the source of NM9 and the drain of NM3 are connected to ground GND. The drain of PM1 is connected to the source of PM4, the drain of PM5 is connected to the source of PM6, the drain of PM7 is connected to the source of PM8, and the drain of PM9 is connected to the source of PM 10. The drain of NM1 is connected to the source of NM4, the drain of NM5 is connected to the source of NM6, the drain of NM7 is connected to the source of NM8, and the drain of NM9 is connected to the source of NM 10. The drains of PM4, PM6, PM8, PM10 are connected to the source of PM 3. The drains of NM4, NM6, NM8, and NM10 are connected to the source of NM 3. The gates of PM1, PM2, PM5, PM7 and PM9 and the gates of NM1, NM2, NM5, NM7 and NM9 are connected together as the input DIN of the time screening circuit. The drains of the PM2 and the NM2, and the gates of the PM3 and the NM3 are connected together to be used as an output end DOUT of the time discrimination circuit. The gates of the PM4, PM6, PM8 and PM10 are respectively connected with an external control signal V_SPL1、V_SPL2、V_SPL3、V_SPL4. The gates of NM4, NM6, NM8 and NM10 are respectively connected with an external control signal V_SPH1、V_SPH2、V_SPH3、V_SPH4。

As shown in figure 3, the whole time discrimination circuit is divided into an upper part and a lower part, wherein the lower part mainly comprises a switch consisting of an NMOS (N-channel metal oxide semiconductor) tube and an NMOS tube and is used for determining the V of the discriminator_THHWherein NM4, NM6, NM8, NM10 are NMOS switches, external V_SPHThe signal is active at high level 1, when V_SPHWhen the number of the MOS switches is 1, the corresponding MOS switches are turned on, and then the MOS tubes of the corresponding branches are also connected into the circuit, so that the purpose of adjusting the width-to-length ratio is achieved. So when four V_SPHWhen the signal takes different values, the threshold value V can be set_THHIs regulated in four steps, and V_SPHThe equivalent width-to-length ratio is sequentially increased along with the arrangement of thermometer codes. When V is_SPH1＝1、V_SPH2＝0、V_SPH3＝0、V_SPHWhen 4 is equal to 0, according toTo obtain In the formula of_nFor electron mobility, C_OXGate capacitance, W is the width of the corresponding MOS transistor, L is the length of the corresponding MOS transistor, V_THHFor the threshold voltage at the transition of the input from low to high, V_THNIs the threshold voltage of the corresponding NMOS transistor. By appropriate selection of NM1, NM3 size, the desired V can be set_SPHAnd the time discrimination circuit changes the equivalent size of the NMOS tube by controlling the conduction of NM4, NM6, NM8 and NM10, wherein the equivalent size is the sum of the width-length ratios of the conducted NMs in NM1, NM5, NM7 and NM 9.

Similarly, the upper part mainly comprises a switch composed of a PMOS (P-channel metal oxide semiconductor) tube and a PMOS tube and is used for determining the V of the discriminator_THL。V_THLCan also be adjusted by the width-to-length ratio of PM1 to PM3, with the relationship betweenWherein V_THPIs the threshold voltage of the PMOS tube. The time discrimination circuit changes the equivalent size of the PMOS tube DP by controlling the conduction of PM4, PM6, PM8 and PM10, and the equivalent size is the sum of the width-length ratios of the conduction PMOS in PM1, PM5, PM7 and PM 9.

As shown in fig. 4, the pulse generating circuit includes eight PMOS, which are: PM11, PM12, PM13, PM14, PM15, PM16, PM17, PM 18. Eight NMOS, respectively: NM11, NM12, NM13, NM14, NM15, NM16, NM17, NM 18. Sources of PM11, PM12, PM13, PM14, PM15, PM16, PM17 and PM18 are connected with a power supply VDD. The sources of NM11, NM12, NM13, NM14, NM15, NM16, NM17, NM18 are all connected to ground GND. The drains of PM11, NM11 are connected to the gates of PM12, NM 12. The drains of PM12, NM12 are connected to the gates of PM13, NM 13. The drains of PM13, NM13 are connected to the gates of PM14, NM15, PM16, NM 16. The drains of PM16, NM16 are connected to the gates of PM17, NM 17. The drains of PM17, NM17 are connected to the gates of PM18, NM 18. The drains of PM18 and NM18 are connected to the gates of PM15 and NM14 as the output TOUT of the pulse generating circuit. The drains of PM15, PM14 are connected to the source of NM 14. The gates of PM11 and NM11 are connected as input TOUT of the pulse generating circuit.

As shown in FIG. 4, the pulse generating circuit mainly comprises three parts, the first part is a buffer circuit, and the PM11, NM11, PM12, NM12, PM13 and NM13 form three buffers, so as to improve the driving capability of the input signal DIN and exceed V_THHThe falling edge signal of (a) is converted to a rising edge signal, which appears at point a. The second part is a delay unit, and PM16, NM16, PM17, NM17, PM18 and NM18 form three delay units, delay the falling edge generated by the buffer by T, and convert the rising edge into the falling edge, wherein the signal appears at point B. The third part is the pulse generation logic, PM14, PM15, NM14, NM15 form a nand gate, thereby converting a falling edge of the input signal TIN into a negative pulse signal TOUT with a pulse width T for the back-end digital circuitry to process.

Simulation result

As shown in FIG. 5, a triangular wave signal DIN is input to the time discriminator circuit to convert V into V_SPL1、V_SPL2、V_SPL3、V_SPL4 is set to 1, 0. Then, the V is put_SPH1、V_SPH2、V_SPH3、V_SPH4 are set to 1, 0, respectively; 1.1, 0; 1, 1, 1, 0; 1.1, 1 and 1, obtaining respective transient simulation results. As can be seen from the figure, V_THH＞V_THLThe delay effect is realized, and the purposes of anti-interference and noise are achieved. It can also be seen from the figure that by adjusting the aspect ratios of NM1, NM5, NM7, NM9 in FIG. 3, the threshold V can be precisely controlled_THHIn this embodiment, the setting is 0.9V, 1.1V, 1.3V, 1.5V, respectively, to achieve the function of controlling the threshold value by the external digital signal.

DIN is the input signal of the time discrimination circuit and the threshold V of the discrimination circuit is determined as shown in FIG. 6_THHThe setting is 1V, it can be seen that when DIN exceeds 1V, the discriminator generates a falling edge signal DOUT, i.e. TIN signal, and then the pulse generating circuit rapidly outputs a negative pulse signal TOUTA negative pulse signal of 30n S width.

As shown in fig. 7, the time discriminator is applied to the radiation detection front-end readout circuit, and joint simulation is performed, the output signal of the front-end readout circuit is a quasi-gaussian waveform, and when the signal amplitude exceeds the set threshold value 1V, DOUT and TOUT can accurately and timely generate corresponding signals.

The time discriminator can completely meet the requirement of a front-end reading circuit of the radiation detector, has simple circuit and low power consumption, and can adjust the threshold value by using an external digital signal and output a pulse signal.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The above examples are to be construed as merely illustrative and not limitative of the remainder of the disclosure. After reading the description of the invention, the skilled person can make various changes or modifications to the invention, and these equivalent changes and modifications also fall into the scope of the invention defined by the claims.