Pulse generation circuit

Abstract

The utility model relates to the technical field of power electronics, and discloses a pulse generating circuit which comprises a modulation circuit and a stable amplification circuit, a first end of the modulation circuit is connected with a first external power supply and a first end of the stable amplification circuit, a second end of the modulation circuit is connected with a second end of the stable amplification circuit, and a third end of the modulation circuit is connected with a second external power supply. The first input end inputs square wave signals, the second input end inputs sawtooth wave signals, and the output end is connected with the input end of the stable amplification circuit; the third end of the stable amplification circuit is connected with a third external power supply; when the voltage of the output end of the stable amplifying circuit rises reversely, the stable amplifying circuit suppresses switch high-voltage avalanche inside the stable amplifying circuit by switching the switch state of the stable amplifying circuit, and therefore stable sharp pulse signals are output. According to the utility model, the stable sharp pulse signal can be output according to the input square wave signal by inhibiting the avalanche of the switch in the stable amplification circuit.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, in particular to a pulse generating circuit. Background Art

[0002] High-speed stable pulse edge generation circuits are commonly found in pulse radar applications and are also found in some civilian security inspection equipment. As society pays more attention to environmental safety, more and more social places need to conduct safety inspections. Non-metallic bottle liquid rapid detection technology based on dielectric constant stands out among various solutions with its unique advantages.

[0003] In the related technical solution, the pulse edge generating circuit obtains a high-speed, accurate, and high-amplitude sharp pulse signal by turning on the sharp pulse signal at the transmitting end to make the avalanche critical state of the transistor. Due to the different dielectric constants of the samples, the received signals will be different. The sharp pulse signal at the receiving end is turned on to sample a section of the waveform, and the sample signal is extracted by the time difference between the sharp pulses at the receiving and transmitting ends. The output waveform is processed and used for identification and judgment. Due to the limited withstand voltage range of the device, in such large voltage limit applications, the pulse generating transistor will be at the edge of the avalanche working area, causing signal instability and affecting the measurement results. Therefore, it is necessary to ensure the stability of the avalanche signal at the high-voltage end, and at the same time, it is necessary to ensure the stability of the sharp pulse signal at the receiving and transmitting ends to avoid high-frequency avalanches, so as to ensure the accuracy of each received signal. Utility Model Content

[0004] Therefore, the technical problem to be solved by the present invention is to solve the problem in the prior art that the switch in the pulse generating circuit vibrates during high voltage avalanche, resulting in the inability to stably output the pulse signal, thereby providing a pulse generating circuit.

[0005] In order to achieve the above object, the utility model provides the following technical solutions:

[0006] The utility model provides a pulse generating circuit, comprising: a modulation circuit and a stable amplifier circuit, wherein the modulation circuit, a first end thereof is connected to a first external power supply and a first end of the stable amplifier circuit, a second end thereof is connected to a second end of the stable amplifier circuit, a third end thereof is connected to a second external power supply, a square wave signal is input to a first input end thereof, a sawtooth wave signal is input to a second input end thereof, an output end thereof is connected to an input end of the stable amplifier circuit, and the modulation circuit is used for switching a switching speed based on the sawtooth wave signal, thereby modulating the square wave signal into a pulse signal and then outputting the signal; the stable amplifier circuit, a third end thereof is connected to a third external power supply, and is used for amplifying the pulse signal and then outputting a sharp pulse signal; when the voltage at the output end of the stable amplifier circuit increases in the reverse direction, the stable amplifier circuit suppresses a switch high voltage avalanche inside the stable amplifier circuit by switching its own switch state, thereby outputting a stable sharp pulse signal.

[0007] The pulse generating circuit provided by the utility model has a modulation circuit that modulates a square wave signal into a pulse signal that is consistent with the sawtooth wave signal frequency based on the switching opening speed of the sawtooth wave of any frequency, that is, when the second input end of the modulation circuit receives a high-frequency sawtooth wave signal, a high-frequency sharp pulse signal is obtained through the action of the modulation circuit and the stable amplifier circuit, thereby improving the response speed and sampling frequency of the subsequent circuit. When the switch in the stable amplifier circuit gradually approaches the avalanche state, the voltage at the output end of the stable amplifier circuit gradually increases, and the stable amplifier circuit reduces the voltage drop at both ends of the switch near the avalanche state by adaptively switching its own switch state, thereby avoiding the avalanche of the switch causing the output sharp pulse signal waveform to jitter, making the output sharp pulse signal clearer and more stable.

[0008] In an optional embodiment, the pulse generating circuit further includes: a shaping circuit, whose input end inputs a square wave signal, whose first end is connected to the first external power supply, and whose output end is connected to the first input end of the modulation circuit, and is used to shape the square wave signal and eliminate the higher harmonics in the square wave signal. The shaping circuit includes: a current source circuit, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a first switch, wherein the current source circuit, whose first end inputs a square wave signal, whose first end is connected to the first end of the first resistor, the first end of the first switch and the first input end of the modulation circuit, whose second end is connected to the first end of the second resistor, whose third end is connected to the first end of the fourth resistor, and whose fourth end is connected to the first end of the third resistor; the first resistor, whose second end is connected to the second end of the second resistor and then to ground; the third resistor, whose second end is connected to the second end of the fourth resistor, the first end of the fifth resistor and the first external power supply; the fifth resistor, whose second end is connected to the first end of the sixth resistor and the control end of the first switch; the sixth resistor, whose second end is connected to the second end of the first switch and then to ground.

[0009] The pulse generating circuit and the shaping circuit provided by the utility model are used for performing preliminary filtering processing on the square wave signal, eliminating the high-frequency harmonics in the square wave signal, making the rising edge of the square wave faster, and improving the clarity of the square wave signal.

[0010] In an optional embodiment, the current source circuit includes: a second switch and a third switch, wherein the second switch has a control end connected to the control end of the third switch, a first end of the third switch and a first end of the second resistor, a first end connected to the first end of the first resistor and a second end connected to the first end of the third resistor; and the third switch has a second end connected to the first end of the fourth resistor.

[0011] In an optional embodiment, the modulation circuit includes: a follower circuit and a first switching circuit, wherein the follower circuit has an input end connected to the output end of the shaping circuit, a first end connected to the first external power supply, a second end connected to the second end of the stabilization amplifier circuit, a third end connected to the first end of the first switching circuit, and a fourth end connected to the second external power supply and the second end of the first switching circuit, and is used to follow the square wave signal to improve the stability of the square wave signal; the first switching circuit has an input end inputting a sawtooth wave signal, and an output end connected to the input end of the stabilization amplifier circuit, and is used to switch the opening speed based on the sawtooth wave signal, thereby modulating the square wave signal into a pulse signal for output.

[0012] The pulse generating circuit provided by the utility model and the following circuit play the role of buffering and following the square wave signal, further improving the stability and clarity of the square wave signal, and improving the driving ability of the square wave signal. By adjusting the frequency of the sawtooth wave to control the opening speed of the first switch circuit, the first switch circuit outputs pulse signals of different frequencies, making the pulse generating circuit more flexible.

[0013] In an optional embodiment, the follower circuit includes: a fourth switch, a fifth switch, a seventh resistor, an eighth resistor, a ninth resistor and a first capacitor, wherein the fourth switch, whose control end is connected to the output end of the shaping circuit, whose first end is connected to the first end of the seventh resistor, the first end of the first capacitor and the first end of the fifth switch, and whose second end is connected to the control end of the fifth switch and the first end of the eighth resistor; the fifth switch, whose second end is connected to the first end of the ninth resistor and the first end of the first switch circuit; the seventh resistor, whose second end is connected to the first external power supply; the first capacitor, whose second end is connected to the first end of the stabilization amplifier circuit; the eighth resistor, whose second end is connected to the second external power supply, the second end of the ninth resistor and the second end of the first switch circuit.

[0014] In an optional embodiment, the first switching circuit includes: a sixth switch, a tenth resistor, an eleventh resistor and a second capacitor, wherein the sixth switch has a first end connected to the third end of the follower circuit, a control end connected to the first end of the tenth resistor, the first end of the eleventh resistor and the first end of the second capacitor, and a second end connected to the input end of the stable amplifier circuit; the tenth resistor has a second end receiving a sawtooth wave signal; the eleventh resistor has a second end connected to the second end of the second capacitor and the fourth end of the follower circuit.

[0015] In an optional embodiment, a stable amplifier circuit includes: an amplifier circuit and a second switching circuit, wherein the amplifier circuit, whose input end is connected to the output end of the modulation circuit, whose first end and second end are respectively connected to the first end and second end of the second switching circuit, and whose third end is connected to the third external power supply and the third end of the second switching circuit, and is used to output a sharp pulse signal after amplifying the pulse signal; the second switching circuit, whose fourth end is connected to the first external power supply and the first end of the modulation circuit, and whose fifth end is connected to the second end of the modulation circuit; when the voltage at the second end of the amplifier circuit increases in reverse, the second switching circuit is turned on, thereby suppressing the switch high-voltage avalanche in the amplifier circuit.

[0016] In an optional embodiment, the amplification circuit includes: a seventh switch, a twelfth resistor, a thirteenth resistor and a third capacitor, wherein the seventh switch, a control end of which is connected to the first end of the second switch circuit and the first end of the twelfth resistor, a first end of which is grounded, and a second end of which is connected to the first end of the thirteenth resistor, the first end of the third capacitor and the second end of the second switch circuit; the twelfth resistor, a second end of which is connected to the output end of the modulation circuit; the thirteenth resistor, a second end of which is connected to the third external power supply and the third end of the second switch circuit; the third capacitor, a second end of which outputs a sharp pulse signal.

[0017] In an optional embodiment, the second switch circuit includes: an eighth switch, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an adjustable resistor, a diode, a fourth capacitor and a fifth capacitor, wherein the fourteenth resistor, a first end thereof is connected to the first end of the amplifier circuit, and a second end thereof is connected to the first end of the eighth switch and the first end of the fifteenth resistor; the fifteenth resistor, a second end thereof is connected to the third end of the amplifier circuit; the eighth switch, a control end thereof is connected to the anode of the diode, the first end of the sixteenth resistor and the first end of the seventeenth resistor, and a second end thereof is grounded; the sixteenth resistor, a second end thereof is connected to the second end of the amplifier circuit; the seventeenth resistor, a second end thereof is connected to the first end of the adjustable resistor and the first end of the fourth capacitor; the second end of the adjustable resistor is connected to the first end of the fifth capacitor and the first end of the modulation circuit; the diode, a cathode thereof is connected to the second end of the fourth capacitor, the second end of the fifth capacitor and the second end of the modulation circuit and then is grounded; when the voltage at the second end of the seventh switch increases in the reverse direction, the eighth switch is turned on to turn on the seventh switch.

[0018] The pulse generating circuit provided by the utility model controls the conduction of the eighth switch through feedback regulation when the voltage at the second end of the seventh switch increases in the reverse direction, thereby turning on the seventh switch in a critical state, thereby avoiding avalanche of the seventh switch causing a jittery sharp pulse signal to be output at the second end. The switch for feedback regulation has low cost and a simple control principle.

[0019] In an optional embodiment, the pulse generating circuit also includes: a reference circuit, a first end of which is connected to the first external power supply, the first end of the modulation circuit and the first end of the stabilization amplifier circuit, and a second end of which is connected to the first end of the shaping circuit, and is used to provide a stable reference voltage for the shaping circuit.

[0020] The pulse generating circuit provided by the utility model can provide a reference voltage for the shaping circuit in the reference circuit. The shaping circuit shapes the amplitude of the square wave according to the size of the reference voltage. At the same time, the amplitude of the square wave signal is controlled by setting the reference voltage of the reference circuit, so that the pulse generating circuit has higher flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 is a composition diagram of a specific example of a pulse generating circuit according to an embodiment of the utility model;

[0023] Figure 2 is a composition diagram of another specific example of a pulse generating circuit according to an embodiment of the utility model;

[0024] Figure 3 is a structural diagram of a specific circuit of a pulse generating circuit according to an embodiment of the utility model;

[0025] Figure 4 It is a composition diagram of another specific example of the pulse generating circuit according to an embodiment of the utility model. DETAILED DESCRIPTION

[0026] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0029] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] This embodiment provides a pulse generating circuit, such as Figure 1 As shown, it includes: a modulation circuit 1 and a stable amplifier circuit 2, wherein the modulation circuit 1 has a first end connected to a first external power supply VCC_+12V and a first end of the stable amplifier circuit 2, a second end connected to a second end of the stable amplifier circuit 2, and a third end connected to a second external power supply VCC_-12V. A square wave signal is input to a first input end, a sawtooth wave signal is input to a second input end, and an output end is connected to an input end of the stable amplifier circuit, and is used to switch the opening speed based on the sawtooth wave signal, thereby modulating the square wave signal into a pulse signal for output.

[0031] like Figure 1 As shown, the third terminal of the stable amplifier circuit 2 is connected to the third external power supply VCC_-70V, which is used to amplify the pulse signal and output a sharp pulse signal; when the voltage at the output end of the stable amplifier circuit 2 increases in the reverse direction, the stable amplifier circuit 2 switches its own switch state to suppress the internal switch high voltage avalanche, thereby outputting a stable sharp pulse signal. Figure 1 The voltages provided by the three external power sources are only used as examples and are not intended to be limiting.

[0032] Specifically, Figure 1As shown, the sawtooth wave signal at the second input end of the modulation circuit 1 is used to control the switching speed of the modulation circuit 1. When a square wave signal is input to the first input end of the modulation circuit 1, the square wave signal is modulated into a pulse signal consistent with the sawtooth wave frequency after passing through the modulation circuit 1 under the action of different switching speeds. The stable amplifier circuit 2 amplifies the pulse signal and outputs a sharp pulse signal.

[0033] Specifically, Figure 1 In the process of turning off the switch in the stable amplifier circuit 2, the voltage drop across the switch inside the stable amplifier circuit 2 increases, causing the switch to be in a critical avalanche state. At this time, the voltage at the output end of the stable amplifier circuit 2 increases in the reverse direction. When the voltage at the output end of the stable amplifier circuit 2 increases in the reverse direction, the stable amplifier circuit 2 switches its own switch state to turn on the switch in the critical avalanche state, suppressing the high-voltage avalanche of the switch, and avoiding the switch in the critical avalanche state from jittering, which causes the output end of the stable amplifier circuit 2 to jitter, thereby outputting a stable spike pulse signal.

[0034] Optionally, the frequency of the pulse signal is consistent with the frequency of the sawtooth wave signal, and the amplitude of the pulse signal is slightly smaller than the amplitude of the square wave signal. Technical personnel in this field can obtain a sharp pulse signal with a desired frequency and desired amplitude by controlling the amplitude of the square wave signal and the frequency of the sawtooth wave signal.

[0035] The pulse generating circuit provided in this embodiment can modulate the square wave signal into a pulse signal with the same frequency as the sawtooth wave signal based on the switching speed of the sawtooth wave of any frequency. That is, when the second input end of the modulation circuit receives the high-frequency sawtooth wave signal, a high-frequency sharp pulse signal is obtained through the action of the modulation circuit and the stable amplifier circuit, thereby improving the response speed and sampling frequency of the subsequent circuit. When the switch in the stable amplifier circuit gradually approaches the avalanche state, the voltage at the output end of the stable amplifier circuit gradually increases. The stable amplifier circuit reduces the voltage drop at both ends of the switch near the avalanche state by switching its own switch state, thereby avoiding the avalanche of the switch causing the output sharp pulse signal waveform to jitter, making the output sharp pulse signal clearer and more stable.

[0036] In some optional embodiments, such as Figure 2 As shown, the pulse generating circuit also includes: a shaping circuit 3, whose input end inputs a square wave signal, whose first end is connected to the first external power supply VCC_+12V, and whose output end is connected to the first input end of the modulation circuit 1, which is used to shape the square wave signal and eliminate the higher harmonics in the square wave signal.

[0037] like Figure 3 As shown, the shaping circuit 3 includes: a current source circuit 31, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a first switch Q1.

[0038] like Figure 3 As shown, the current source circuit 31, whose first end inputs a square wave signal, whose first end is connected to the first end of the first resistor R1, the first end of the first switch Q1 and the first input end of the modulation circuit 1, whose second end is connected to the first end of the second resistor R2, whose third end is connected to the first end of the fourth resistor R4, and whose fourth end is connected to the first end of the third resistor R3. The first resistor R1, whose second end is connected to the second end of the second resistor R2 and then to ground; the third resistor R3, whose second end is connected to the second end of the fourth resistor R4, the first end of the fifth resistor R5 and the first external power supply VCC_+12V; the fifth resistor R5, whose second end is connected to the first end of the sixth resistor R6 and the control end of the first switch Q1; the sixth resistor R6, whose second end is connected to the second end of the first switch Q1 and then to ground.

[0039] like Figure 3 As shown, the current source circuit 31 includes: a second switch Q2 and a third switch Q3, wherein the second switch Q2 has a control end connected to the control end of the third switch Q3, a first end of the third switch Q3 and a first end of the second resistor R2, a first end connected to the first end of the first resistor R1, and a second end connected to the first end of the third resistor R3; and the third switch Q3 has a second end connected to the first end of the fourth resistor R4.

[0040] like Figure 4 As shown, the pulse generating circuit also includes: a reference circuit 4, a first end of which is connected to the first external power supply VCC_+12V, the first end of the modulation circuit 1 and the first end of the stabilization amplifier circuit 2, and a second end of which is connected to the first end of the shaping circuit 3, and is used to provide a stable reference voltage for the shaping circuit 3.

[0041] Specifically, Figure 4 In the figure, by setting the parameters of the controllable precision voltage regulator TL431 in the reference circuit 4, the reference circuit 4 outputs a reference voltage, and the shaping circuit 3 shapes the amplitude of the square wave according to the size of the reference voltage, that is, the amplitude of the square wave signal can be adjusted by setting the size of the reference voltage output by the reference circuit 4, thereby adjusting the amplitude of the pulse signal and the sharp pulse signal.

[0042] Specifically, Figure 3 Take the structure shown as an example, Figure 3In the embodiment, the reference circuit 4 outputs a stable reference voltage according to the first external power supply, and the square wave signal is shaped into a square wave signal with stable high and low levels under the action of the reference voltage. The square wave signal first passes through the current mirror circuit composed of the second switch Q2 and the third switch Q3. The second switch Q2 and the third switch Q3 both work in the amplification area. The square wave signal current passing through the current mirror circuit rises faster or even overshoots under the action of the high impedance switch, thereby achieving the effect of eliminating spikes and high-order harmonics and shaping the initial waveform. When the square wave signal is at a high level, the first switch Q1 is turned off, and the first end of the first switch Q1 outputs a high level; when the square wave signal is at a low level, the first switch Q1 is turned on, and the first end of the first switch Q1 outputs a low level. The first switch Q1 continuously switches the on-off state according to the level of the square wave signal, thereby inputting the shaped square wave signal to the first input end of the modulation circuit 1.

[0043] like Figure 4 As shown, the modulation circuit 1 includes: a follower circuit 11 and a first switch circuit 12, wherein the follower circuit 11, whose input end is connected to the output end of the shaping circuit 3, whose first end is connected to the first external power supply VCC_+12V, whose second end is connected to the second end of the stable amplifier circuit 2, whose third end is connected to the first end of the first switch circuit 12, and whose fourth end is connected to the second external power supply VCC_-12V and the second end of the first switch circuit 12, is used to follow the square wave signal to improve the stability of the square wave signal; the first switch circuit 12, whose input end inputs a sawtooth wave signal, whose output end is connected to the input end of the stable amplifier circuit 2, is used to switch the opening speed based on the sawtooth wave signal, thereby modulating the square wave signal into a pulse signal for output.

[0044] like Figure 3 As shown, the follower circuit 11 includes: a fourth switch Q4, a fifth switch Q5, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9 and a first capacitor C1, wherein the fourth switch Q4 has a control end connected to the output end of the shaping circuit 3, a first end connected to the first end of the seventh resistor R7, the first end of the first capacitor C1 and the first end of the fifth switch Q5, and a second end connected to the control end of the fifth switch Q5 and the first end of the eighth resistor R8.

[0045] like Figure 3 As shown, the fifth switch Q5, the second end of which is connected to the first end of the ninth resistor R9 and the first end of the first switch circuit 12; the seventh resistor R7, the second end of which is connected to the first external power supply VCC_+12V; the first capacitor C1, the second end of which is connected to the first end of the stable amplifier circuit 2; the eighth resistor R8, the second end of which is connected to the second external power supply VCC_-12V, the second end of the ninth resistor R9 and the second end of the first switch circuit 12.

[0046] like Figure 3As shown, the first switch circuit 12 includes: a sixth switch Q6, a tenth resistor R10, an eleventh resistor R11 and a second capacitor C2, wherein the sixth switch Q6, a first end thereof is connected to the third end of the follower circuit 11, a control end thereof is connected to the first end of the tenth resistor R10, the first end of the eleventh resistor R11 and the first end of the second capacitor C2, and a second end thereof is connected to the input end of the stable amplifier circuit 2; the tenth resistor R10, a second end thereof receives a sawtooth wave signal; the eleventh resistor R11, a second end thereof is connected to the second end of the second capacitor C2 and the fourth end of the follower circuit 11.

[0047] Specifically, Figure 3 Take the structure shown as an example, Figure 3 In the embodiment, the fourth switch Q4 and the fifth switch Q5 with a common collector play the role of buffering and increasing the output driving capability. When a high-level sawtooth wave signal with a certain frequency is input to the second input terminal of the first switch circuit 12, no matter the level of the base of the sixth switch Q6 is 0V or the highest amplitude of the sawtooth wave, the emitter junction of the sixth switch Q6 will be turned on when its emitter is at a high level, but the turn-on speed of the sixth switch Q6 is controlled by the frequency of the sawtooth wave signal, that is, the emitter junction of the sixth switch Q6 switches the turn-on speed according to the frequency of the sawtooth wave when the square wave signal is at a high level. Under the action of the sixth switch Q6 with different turn-on speeds, the square wave signal causes the collector voltage of the sixth switch Q6 to change at different rates, and the collector of the sixth switch Q6 outputs a pulse signal with a frequency consistent with the frequency of the sawtooth wave signal.

[0048] like Figure 4 As shown, the stable amplifier circuit 2 includes: an amplifier circuit 21 and a second switch circuit 22, wherein the amplifier circuit 21, whose input end is connected to the output end of the modulation circuit 1, whose first end is connected to the first end of the second switch circuit 22, whose second end is connected to the second end of the second switch circuit 22 and then grounded, whose third end is connected to the third external power supply VCC_-70V and the third end of the second switch circuit 22, and is used to output a sharp pulse signal after amplifying the pulse signal; the second switch circuit 22, whose fourth end is connected to the first external power supply VCC_+12V and the first end of the modulation circuit 1, and whose fifth end is connected to the second end of the modulation circuit 1; when the voltage at the second end of the amplifier circuit 21 increases in reverse, the second switch circuit 22 is turned on, thereby suppressing the switch high-voltage avalanche in the amplifier circuit 21.

[0049] like Figure 3As shown, the amplifier circuit 21 includes: a seventh switch Q7, a twelfth resistor R12, a thirteenth resistor R13 and a third capacitor C3, wherein the seventh switch Q7, whose control end is connected to the first end of the second switch circuit 22 and the first end of the twelfth resistor R12, whose first end is grounded, and whose second end is connected to the first end of the thirteenth resistor R13, the first end of the third capacitor C3 and the second end of the second switch circuit 22; the twelfth resistor R12, whose second end is connected to the output end of the modulation circuit 1; the thirteenth resistor R13, whose second end is connected to the third external power supply VCC_-70V and the third end of the second switch circuit 22; the third capacitor C3, whose second end outputs a spike pulse signal.

[0050] like Figure 3 As shown, the second switch circuit 22 includes: an eighth switch Q8, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an adjustable resistor R18, a diode D1, a fourth capacitor C4 and a fifth capacitor F5, wherein the fourteenth resistor R14 has a first end connected to the first end of the amplifier circuit 21, and a second end connected to the first end of the eighth switch Q8 and the first end of the fifteenth resistor R15; the fifteenth resistor R15 has a second end connected to the third end of the amplifier circuit 21; the eighth switch Q8 has a control end connected to the anode of the diode D1, the first end of the sixteenth resistor R16 and the first end of the seventeenth resistor R17, and a second end grounded.

[0051] like Figure 3 As shown, the second end of the sixteenth resistor R16 is connected to the second end of the amplifier circuit 21; the second end of the seventeenth resistor R17 is connected to the first end of the adjustable resistor R18 and the first end of the fourth capacitor C4; the second end of the adjustable resistor R18 is connected to the first end of the fifth capacitor C5 and the first end of the modulation circuit 1; the cathode of the diode D1 is connected to the second end of the fourth capacitor C4, the second end of the fifth capacitor C5 and the second end of the modulation circuit 1 and then grounded; when the voltage at the second end of the seventh switch Q7 increases in the reverse direction, the eighth switch Q8 is turned on to turn on the seventh switch Q7.

[0052] Specifically, Figure 3 Take the structure shown as an example, Figure 3 In the embodiment, the pulse signal is input to the base of the seventh switch Q7 through the twelfth resistor R12. Since the emitter voltage of the seventh switch Q7 is -70V and the collector is grounded, when the base of the seventh switch Q7 is at a high level, the seventh switch Q7 is turned on, and the emitter and collector are connected. The pulse signal is isolated from the emitter and collector of the seventh switch Q7 by the third capacitor C3, and a sharp pulse signal is output.

[0053] Specifically, Figure 3 Take the structure shown as an example, Figure 3In the process of turning off the seventh switch Q7, the voltage drop across the collector and the emitter will gradually increase. When the voltage drop increases and exceeds the critical state of the seventh switch Q7, the seventh switch Q7 will be in an avalanche state. In order to avoid the emitter outputting a jittering sharp pulse signal when the seventh switch Q7 is in an avalanche state, the base of the eighth switch Q8 is connected to the emitter of the seventh switch Q7 through the sixteenth resistor R16. During the turning off of the seventh switch Q7, the voltage drop between the collector and the emitter of the seventh switch Q7 increases. Since the emitter voltage of the seventh switch Q7 is -70V and the collector is grounded, the emitter voltage gradually increases in the reverse direction. After the base voltage of the eighth switch Q8 is gradually pulled below the emitter voltage, the eighth switch Q8 is turned on, raising the base voltage of the seventh switch Q7. The seventh switch Q7 is turned on, and the voltage drop gradually decreases, thereby suppressing the avalanche of the seventh switch Q7. The emitter of the seventh switch Q7 outputs a stable sharp pulse signal through the third capacitor.

[0054] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A pulse generating circuit, characterized in that: include: Modulation circuit and stable amplifier circuit, wherein: A modulation circuit, wherein a first end of the modulation circuit is connected to a first external power source and a first end of the stable amplifier circuit, a second end of the modulation circuit is connected to a second end of the stable amplifier circuit, a third end of the modulation circuit is connected to a second external power source, a square wave signal is input to a first input end of the modulation circuit, a sawtooth wave signal is input to a second input end of the modulation circuit, an output end of the modulation circuit is connected to an input end of the stable amplifier circuit, and the modulation circuit is used to switch the switching speed based on the sawtooth wave signal, thereby modulating the square wave signal into a pulse signal for output; A stable amplifier circuit, the third end of which is connected to a third external power source, and is used to amplify the pulse signal and then output a sharp pulse signal; When the voltage at the output end of the stable amplifier circuit increases in the reverse direction, the stable amplifier circuit switches its own switch state to suppress the switch avalanche inside it, thereby outputting a stable spike pulse signal.

2. The pulse generating circuit according to claim 1, characterized in that: Also includes: A shaping circuit, whose input end inputs a square wave signal, whose first end is connected to a first external power supply, and whose output end is connected to a first input end of the modulation circuit, is used to shape the square wave signal and eliminate high-order harmonics in the square wave signal. The shaping circuit includes: a current source circuit, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a first switch, wherein: a current source circuit, wherein a square wave signal is input to a first end of the current source circuit, the first end of the current source circuit is connected to a first end of the first resistor, a first end of the first switch and a first input end of the modulation circuit, the second end of the current source circuit is connected to a first end of the second resistor, the third end of the current source circuit is connected to a first end of the fourth resistor, and the fourth end of the current source circuit is connected to a first end of the third resistor; A first resistor, a second end of which is connected to the second end of the second resistor and then grounded; a third resistor, a second end of which is connected to the second end of the fourth resistor, the first end of the fifth resistor and the first external power source; a fifth resistor, a second end of which is connected to the first end of the sixth resistor and the control end of the first switch; A sixth resistor, a second end of which is connected to the second end of the first switch and then grounded.

3. The pulse generating circuit according to claim 2, characterized in that: The current source circuit includes: a second switch and a third switch, wherein: A second switch, whose control end is connected to the control end of the third switch, the first end of the third switch and the first end of the second resistor, whose first end is connected to the first end of the first resistor and whose second end is connected to the first end of the third resistor; A third switch has a second end connected to the first end of the fourth resistor.

4. The pulse generating circuit according to claim 2, characterized in that: The modulation circuit includes: a follower circuit and a first switch circuit, wherein: A follower circuit, whose input end is connected to the output end of the shaping circuit, whose first end is connected to the first external power supply, whose second end is connected to the second end of the stable amplifier circuit, whose third end is connected to the first end of the first switch circuit, and whose fourth end is connected to the second external power supply and the second end of the first switch circuit, and which is used to follow the square wave signal to improve the stability of the square wave signal; The first switch circuit has a sawtooth wave signal input to its input end and an output end connected to the input end of the stable amplifier circuit. The first switch circuit is used to switch the opening speed based on the sawtooth wave signal, thereby modulating the square wave signal into a pulse signal for output.

5. The pulse generating circuit according to claim 4, characterized in that: The follower circuit includes: a fourth switch, a fifth switch, a seventh resistor, an eighth resistor, a ninth resistor and a first capacitor, wherein: a fourth switch, whose control end is connected to the output end of the shaping circuit, whose first end is connected to the first end of the seventh resistor, the first end of the first capacitor and the first end of the fifth switch, and whose second end is connected to the control end of the fifth switch and the first end of the eighth resistor; a fifth switch, a second end of which is connected to the first end of the ninth resistor and the first end of the first switch circuit; a seventh resistor, a second end of which is connected to the first external power source; A first capacitor, a second end of which is connected to the first end of the stable amplifier circuit; An eighth resistor, a second end of which is connected to the second external power source, the second end of the ninth resistor and the second end of the first switch circuit.

6. The pulse generating circuit according to claim 4, characterized in that: The first switch circuit includes: a sixth switch, a tenth resistor, an eleventh resistor and a second capacitor, wherein: a sixth switch, a first end of which is connected to the third end of the follower circuit, a control end of which is connected to the first end of the tenth resistor, the first end of the eleventh resistor and the first end of the second capacitor, and a second end of which is connected to the input end of the stable amplifier circuit; a tenth resistor, a second end of which receives the sawtooth wave signal; The second end of the eleventh resistor is connected to the second end of the second capacitor and the fourth end of the follower circuit.

7. The pulse generating circuit according to claim 1, characterized in that: The stable amplifier circuit comprises: an amplifier circuit and a second switch circuit, wherein: an amplifier circuit, whose input end is connected to the output end of the modulation circuit, whose first end and second end are respectively connected to the first end and second end of the second switch circuit, and whose third end is connected to the third external power supply and the third end of the second switch circuit, and is used to amplify the pulse signal and then output a sharp pulse signal; A second switch circuit, a fourth end of which is connected to the first external power source and the first end of the modulation circuit, and a fifth end of which is connected to the second end of the modulation circuit; When the voltage at the second end of the amplifier circuit increases in reverse direction, the second switch circuit is turned on, thereby suppressing the switch avalanche in the amplifier circuit.

8. The pulse generating circuit according to claim 7, characterized in that: The amplifier circuit includes: a seventh switch, a twelfth resistor, a thirteenth resistor and a third capacitor, wherein: a seventh switch, whose control end is connected to the first end of the second switch circuit and the first end of the twelfth resistor, whose first end is grounded, and whose second end is connected to the first end of the thirteenth resistor, the first end of the third capacitor, and the second end of the second switch circuit; a twelfth resistor, a second end of which is connected to the output end of the modulation circuit; a thirteenth resistor, a second end of which is connected to the third external power supply and the third end of the second switch circuit; The third capacitor has a second terminal that outputs the spike pulse signal.

9. The pulse generating circuit according to claim 8, characterized in that: The second switch circuit includes: an eighth switch, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an adjustable resistor, a diode, a fourth capacitor and a fifth capacitor, wherein: a fourteenth resistor, a first end of which is connected to the first end of the amplifier circuit, and a second end of which is connected to the first end of the eighth switch and the first end of the fifteenth resistor; a fifteenth resistor, a second end of which is connected to the third end of the amplifier circuit; an eighth switch, a control end of which is connected to the anode of the diode, the first end of the sixteenth resistor and the first end of the seventeenth resistor, and a second end of which is grounded; a sixteenth resistor, a second end of which is connected to the second end of the amplifier circuit; A seventeenth resistor, a second end of which is connected to the first end of the adjustable resistor and the first end of the fourth capacitor; an adjustable resistor, a second end of which is connected to the first end of the fifth capacitor and the first end of the modulation circuit; a diode, a cathode of which is connected to the second end of the fourth capacitor, the second end of the fifth capacitor and the second end of the modulation circuit and then grounded; When the voltage at the second end of the seventh switch reverses and increases, the eighth switch is turned on to turn on the seventh switch.

10. The pulse generating circuit according to claim 2, characterized in that: Also includes: A reference circuit, whose first end is connected to the first external power supply, the first end of the modulation circuit and the first end of the stable amplifier circuit, and whose second end is connected to the first end of the shaping circuit, is used to provide a stable reference voltage for the shaping circuit.

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