CN1015227B - Stepless tubes current control device for x-ray instrument - Google Patents

Stepless tubes current control device for x-ray instrument

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Publication number
CN1015227B
CN1015227B CN 90103459 CN90103459A CN1015227B CN 1015227 B CN1015227 B CN 1015227B CN 90103459 CN90103459 CN 90103459 CN 90103459 A CN90103459 A CN 90103459A CN 1015227 B CN1015227 B CN 1015227B
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circuit
current
input
resistance
output
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CN 90103459
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CN1048644A (en
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汪鲜
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XUZHOU MINE ADMINISTRATION
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XUZHOU MINE ADMINISTRATION
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Abstract

The present invention provides a stepless control device for electric current of an x-ray machine tube. The present invention is composed of a comparison integral amplifying circuit, a linear photoelectric coupling circuit, an undercurrent signal circuit, an overcurrent signal circuit, a pulse modulated circuit, a square wave and sine wave waveform transform circuit, a full wave rectifying circuit, a current regulation circuit, a current negative feedback circuit, a pulse generation and delay circuit, and a power supply circuit. The present invention has high control accuracy on x-ray tube filament current, good current regulation performance and good power supply loop compatibility with the existing X-ray device tube filament, and has the undercurrent and overcurrent warning function. When matched with a high resolution DA converter of an x-ray electronic computer control system for controlling, the present invention reaches the primary current resolution of 0.1 mA of a filament transformer and the current regulation accuracy of +/-0.1 mA.

Description

Stepless tubes current control device for x-ray instrument
The invention belongs to a kind of current control circuit, be applicable to the stepless control of medical x-ray machine tube current.
Current, it is very universal and extensive in medical science that X-ray is taken the photograph sheet, but how to improve the quality of X-ray sheet, is a complexity and stubborn problem always.Owing to take the photograph the complex process of sheet, influencing factor is a lot, as: different patients' physical condition difference, then exposure factor (tube voltage kV tube current mA and time for exposure S) also should be different, human body is thrown on the position of photograph because of individual different its varied in thickness is a normal curve that rises gradually and descend, so also should have less regulating power to its various conditions of taking the photograph sheet.And, the working method of dynamic correction has been proposed again for the X-ray machine system is accurately exported.So just require machine to carry out accurate step-less adjustment to tube voltage kV, tube current mA, but, the tube current of existing X line machine is to come stepping to select with resistance, and stepping is thicker, can not be according to the electric current of the stepless control X-ray of actual needs pipe, thereby breakpoint appears in tube current control, can't satisfy the needs of production high-quality rabat.
The objective of the invention is to design a kind of tube current stepless control device of the X of being used for line generation systems.
The X-ray pipe is actual to be cathode ray tube, attract to collide the purpose that realizes launching the X line by the filament emission of negative electrode and the superhigh pressure of anode, the penetration power of X line depends on tube voltage kV, and its amount depends on anode current mA(or claim tube current), tube current mA and tube voltage kV in general, the relation of heater current A is as follows:
mAcoA n·kv
Therefore, if a kV and mA will be arranged, a heater current A must be arranged, the present invention has discarded the method that present X-ray system adopts resistance control heater current, thereby a kind ofly realize high-precision AC constant-current stabilizer to the stepless control of X line generation systems tube current, i.e. X line machine tube current stepless control device by stepless control heater current A and design.
The x-ray tube current stepless control device of the present invention's design is by comparing integrating amplification circuit, and linear photoelectric coupled circuit, undercurrent and over-current signal circuit, pulse modulated circuit, square wave sine waveform translation circuit, full-wave rectifying circuit, matrix current adjustment circuit, current negative feedback circuit, pulse generation and delay circuit and power-supply circuit constitute.The formation and the principle of each circuit are as described below:
1. compare integrating amplification circuit
Its structure is an operational amplifier I CiThe operational amplification circuit that constitutes with comparison integral property, it has two inputs, anti-phase input is from the aanalogvoltage of the DA transducer output of X line computer machine control system, in-phase input end is from current feedback circuit, and be that a dominant frequency is the dc pulse voltage of 2 times of supply frequencies from the voltage of current feedback terminal, in order to obtain straight signal, avoid entire circuit in control, to produce vibration, so with C at output 1Across the output and the inverting input of amplifier, make this circuit have integral property.
2. linear photoelectric coupled circuit
The output signal that will compare integrating amplification circuit by circuit at the corresponding levels reaches the purpose that insulate on the circuit and the signal transmission can be pass by with light electric coupling method.The photoelectricity coupling circuit is output as PNP pipe emitter-coupled circuit, and it flows through the electric current I=(V of light-emitting diode 1-0.7)/R 5(V 1Input voltage for circuit at the corresponding levels), 0.7 is the pressure drop of triode base radio, diode D 1And R 4Positive voltage is clamped to ground voltage.Because the precision of whole device and the linearity depend on the precision and the linearity of comparison integrating amplification circuit and current negative feedback circuit, not strict to other circuit requirements, so circuit at the corresponding levels adopts a common photoelectric coupler, has certain linear degree of coupling in 5～20mA scope.Its coupling electric current in the past is at R 6On formed a voltage and removed subordinate's circuit, so far, the coupling of the signal of front stage circuits and late-class circuit has been accused and has been finished, and makes inter-stage not have the contact of electricity, the state of insulation of level before and after historical facts or anecdotes has showed.Avoided front stage circuits (generally linking to each other) to take place with the situation that late-class circuit (linking to each other with extraneous power supply) interferes with each other with computer hardware.
3. undercurrent and over-current signal circuit
Undercurrent and over-current signal circuit are by two voltage comparator I C2, I C3Constitute, by R 9, W 1, W 2Form its alarm voltage thresholding, when appearring being lower than in the output that compares integrating amplification circuit, the undercurrent value (opens circuit for X-ray filament administration of power supply generally speaking, and current feedback mechanism breaks down) time, then the output of undercurrent comparator is exported a high level and is removed to control the undercurrent warning device.When the output of higher level's circuit occurs being higher than the overcurrent thresholding (puncture short and other faults appear in the high-power adjustment pipe of level after being generally circuit), then the output of overcurrent comparator is exported high level control overcurrent warning device.
4. square wave sine waveform translation circuit
This grade circuit is the band pass filter that a low-pass active filter and high pass active filter series connection constitute, the logical frequency f of its band is identical with supply frequency, so when its input is imported the square-wave signal of one frequency=f, just can obtain very little, the same sine waveform of a distortion factor at its output with square wave frequency, but because of the leading or hysteresis on the band pass filter phase place, the sine wave of its output and the square wave of input have a fixing phase difference on phase place.
5. full-wave rectifying circuit
Circuit at the corresponding levels is one of citation form of computing circuit " a signed magnitude arithmetic(al) circuit ", and that different is amplifier I in the second level in its circuit C7Feedback resistance R 21, be not to be connected across I C7Output and inverting input, but be connected across thereafter level matrix current adjustment circuit power tube T 4Emitter and I C7Inverting input between, when its input is imported a sinusoidal signal Vi, level matrix current adjustment circuit power tube T thereafter 4Emitter resistance R 24On, the voltage waveform signal of a sinusoidal wave full-wave rectification just appears, require R in the circuit 16=R 18=R 26=R 19=2R 20' and error＜1 ‰.
6. matrix current adjustment circuit
Circuit at the corresponding levels is the matrix current adjustment circuit of a high power valve, when single tube power is not enough, a plurality of pipe parallel connections can be made the base stage and the T of a plurality of pipes 4Base stage connect together collector electrode and T 4Collector electrode connect together equal permanent resistance and T that emitter adds by other 4Emitter resistance R 24The hot junction connect together.This high power valve T 4By full-wave rectifying circuit and X spool filament transformer just the utmost point summation current transformer connect and receives in the AC power of filament power supply size and the waveform and the high power valve T of electric current in its interchange loop 4The size of current that is flow through is relevant with waveform, and also is subjected to clamping down on of extraneous AC power waveform.Be size of current and the waveform that the waveform of the size of current that flows through in the high power valve and waveform and extraneous power supply has determined loop, so, when the input voltage waveform of matrix current adjustment circuit with adjust pipe T 4The voltage waveform of collector electrode is then adjusted pipe T with frequency, same phase time 4In this interchange loop, just be equivalent to a pure resistance, under the control of front stage circuits, stablize the electric current that this exchanges loop.T 4With T 3Be a compound emitter-coupled circuit, its loop current I only depends on the absolute value of the input voltage Vi of prime full-wave rectifying circuit, i.e. I=|Vi/R 24|, so (voltage must be greater than a set-point, i.e. T in the variation of extraneous supply voltage 4On the pressure drop of 20V must be arranged) variation of electric current in the loop is had nothing to do, thereby embodied the characteristic of current stabilization.In real work, input voltage is one group and T just 4With frequently, the sinusoidal wave full-wave rectification pulsating voltage of homophase, so this circuit has exchanging the stable control of loop current, the size of its alternating current depends on the height of Vi, i.e. I Hand over=Vi/R 24
Because the above voltage of 50KV is arranged on the filament of X spool over the ground, can be coupled to by the primary inductance of filament transformer and exchange on the loop, thereby the elements such as adjustment pipe in the circuit are caused infringements such as puncture, so in side circuit, except to T 4BV c
Figure 90103459_IMG2
oOutside the requirement＞1000V, also must add pulse eliminating circuit, C 6R 25The resistance capaciting absorpting circuit, the D that form 9With D 10For the voltage-stabiliser tube phase anti-series about voltage stabilizing value 500V on loop, after the pulse of＞500V then can be clamped to 500V with it, and these two groups of protective circuits have been arranged, i.e. each components and parts in the protective circuit reliably.
Current transformer is reflected in the current feedback circuit after with the electric current mutual inductance in the loop, requirement to this current transformer is that the mutual inductance ratio is 100: 1, when electric current is 100～500mA in the loop, the secondary short circuited electric current of instrument transformer is 1～5mA, and its linearity is had certain requirement.
7. current negative feedback circuit
The effect of this circuit is the electric current power in the loop to be changed to direct voltage feed back to the comparison integrating amplification circuit.So the first order of circuit is a current-to-voltage converter, grips inhibition altogether for what improve circuit, adopts the symmetry input R in the circuit 26=R 27The time, its output voltage V 0=-2I 0R 270The circuit second level is the signed magnitude arithmetic(al) circuit, when input one alternating voltage, is input as a full-wave rectified voltage.
This circuit is the feedback circuit in the entire circuit, its precision, linearity and stability have determined precision, the linearity and stable of entire circuit, in the circuit of historical facts or anecdotes border, all amplifiers in this circuit are all adopted high accuracy, the discharge circuit that high stable and low temperature float (as OP-07), the type that all resistance all adopt high accuracy and low temperature to float.
8. pulse generation and delay circuit
The effect of this circuit is to obtain a series of and the same square-wave signal frequently of power supply, and will be defeated by pulse modulated circuit after its delay, to finish the modulation of photoelectricity coupled signal, its delayed action is to compensate the difference on the phase place in the square wave sine waveform conversion process, and the waveform that makes the ground level input voltage of adjusting pipe and the waveform of its collector electrode control voltage are with frequency, homophase.
The first order of circuit is a supply frequency square wave generation circuit, is essentially voltage comparator, imports an alternating voltage, thereby obtains a square wave identical with supply frequency at its output.I C11Be terminal voltage comparator (as LM311) for OC output, thus very convenient in application, do not need input voltage is carried out rectification, D 13With D 14Effect input voltage is clamped to 0.7V, with the protection voltage comparator input.The second level of circuit is the overall pulse delay circuit, will be carried out high-precision all-wave by the square wave of prime input and postpone, and circuit is by XOR gate I C14, monostable circuit I C12, and d type flip flop I C13Constitute, time of delay is by W 4And C 7Decision.Its principle is: added XOR gate can alternately be taken out the rising edge and the trailing edge trigger impulse of signal before the monostable circuit trigger end, and circuit arrives W with its pulse daley 4And C 7Send after the time of defined, after the d type flip flop that connects whenever obtain a monostable pulse just upset be once, on the one hand make XOR gate can alternately finish homophase and anti-phase function in time, become the full circuit and square-wave that output one accurately postpones on the one hand, time of delay scalable W 4Change.
9. power-supply circuit
This circuit for the pulse generation delay circuit supplying with at different levels after the photoelectrical coupler and be attached thereto ± the 15V low-tension supply.Comparison integrating amplification circuit before the photoelectrical coupler and the current negative feedback circuit that is attached thereto are then supplied with by X line computer machine control system power supply, and electricity is irrelevant therewith, thereby realize the insulation on the circuit.
This circuit is a common power of alterating and direct current translation circuit, comprises rectification D 15, D 16, D 17, D 4, filtering C 8-C 13With voltage stabilizing I C15, I C16, adopt fixing circuit of three-terminal voltage-stabilizing integrated to make it simple and reliable, it is output as two groups of power supplys altogether, and voltage is ± 15V.
The advantage of the X line machine tube current stepless control device of the present invention's design is:
1, established the basis of the tube current of x-ray generator being carried out step-less adjustment, the method for work of coupled computer error dynamics correction can be carried out stepless accurate output to X line machine tube current.
2. owing to adopted the current stabilization of circuit, discarded traditional saturation core regulator, thereby the variation to supply frequency is insensitive, survey factually, during supply frequency variation ± 3HZ, electric current does not have significant change, circuit precision height, steady good fluidity, when supply voltage was 180-300V, electric current did not have significant change, actual measurement (scope 50mA～float less than 6/10000ths when 500mA) interior temperature is floated.
3. this device compatible good to the filament current supply circuit of existing X line machine do not need to change any data and the power supply of former filament transformer.
4. undercurrent and over current fault signal can be provided, help the protection and the self diagnosis of machine.
5. preceding late-class circuit is a state of insulation, and inter-stage does not have the contact of electricity, has avoided front stage circuits (generally linking to each other with computer light current circuit) to interfere with each other with late-class circuit (late-class circuit links to each other with extraneous 220V power supply).
6. reliable and stable, on the X wire system, used 3 years, it is inferior surplus in the of 10,000 to expose altogether, and fault-free takes place.
Fig. 1, X line machine tube current stepless control device circuit diagram
The present invention will be further described with embodiment below in conjunction with accompanying drawing:
The circuit diagram of the X line machine tube current stepless control device that the present invention proposes as shown in Figure 1, its circuit constitute and annexation as follows:
1.X line machine tube current stepless control device is by relatively integrating amplification circuit, undercurrent and over-current signal circuit, linear photoelectric coupled circuit, square wave sine waveform translation circuit, full-wave rectifying circuit, matrix current adjustment circuit, current negative feedback circuit, pulse generation and delay circuit and power-supply circuit constitute.
2. compare integrating amplification circuit by operational amplifier I C1, integrating capacitor C 1, feedback resistance R 3With input resistance R 1, R 2Constitute I C1In-phase input end pass through R 2The output that connects current feedback circuit, I C1Inverting input passes through R 1The voltage that connects the DA transducer output of X line computer machine control system.
3. linear photoelectric coupled circuit is managed T by PNP 1, light-emitting diode-phototriode photoelectrical coupler G, resistance R 4, R 5, R 6, diode D 1Constitute its input T 1Base stage pass through R 4Be connected with the output that compares integrating amplification circuit, the anode of the light-emitting diode in the photoelectrical coupler meets T 1Collector electrode, negative electrode connects the low pressure negative supply of X line computer machine control system, the collector electrode of the phototriode of photoelectrical coupler connects the positive supply of this device; Emitter passes through R 6Connect this device power supply ground end.
4. undercurrent and over-current signal circuit are by voltage comparator I C2, I C3, resistance R 7, R 8, R 9, potentiometer W 1, W 2, constitute its undercurrent voltage comparator I C2In-phase input end and the inverting input of overcurrent voltage comparator respectively by input resistance R 7, R 8Join R with the output that compares integrating amplification circuit 9, W 1, W 2Form between the power supply ground end and negative supply that a voltage divider is connected across X line computer machine control system, and R 9With W 1The termination I that joins C2End of oppisite phase, W 1With W 2Meet termination I C3In-phase end;
5. pulse modulated circuit is by triode T 2Resistance R 10, R 11Form, its emitter connects the ground end of this device power supply, and collector electrode passes through R 10Join with the emitter of the phototriode of photoelectricity coupling circuit, base stage is passed through R 11With pulse delay circuit d type flip flop I C13The Q output join;
6. square wave sine waveform translation circuit is a band pass filter, and the logical frequency of its band is identical with ac power frequency, by amplifier I C4, I C5, capacitor C 2, C 3, C 4, C 5, resistance R 12, R 13, R 14, R 15Constitute its input termination pulse modulated circuit T 2Collector electrode.
7. the positive current circuit of all-wave is by I C6, I C7, switching diode D 2, the D3 resistance R 16, R 17, R 18, R 19, R 20, R 21, R 22A kind of signed magnitude arithmetic(al) circuit that constitutes, that different is feedback resistance R 21Should meet I C7One of output has terminated at matrix current adjustment circuit T 4Emitter on, the input of its input termination square wave sine waveform translation circuit.
8. matrix current adjustment circuit is by PNP triode T 3, T 4, rectifier diode D 5, D 6, D 7, D 8, voltage stabilizing didoe D 9, D 10, resistance R 23, R 24, R 25, capacitor C 6, current transformer B 2, x-ray machine filament transformer B 1Elementary formation, T 3Collector electrode connect the positive supply of this device, emitter passes through R 23Join with the ground end of this device power supply, and and T 4Base stage join T 3Base stage and the output of full-wave rectifying circuit join T 4Emitter pass through R 21With I C7Inverting input join, and also pass through R 24Join D with the power supply ground end of this device 5, D 6, D 7, D 8The full-wave rectifying circuit of forming; One ac input end and current transformer B 2Elementary and filament transformer B 1An end of elementary series connection AC power; Its another ac input end directly connects the other end of AC power.Series connection inserts C between two ac input ends 6And R 25, and seal in the relative D of an anticathode 9, D 10, the cathode output end of its full-wave rectifying circuit meets T 4Collector electrode; The ground end of its cathode output end and this device power supply joins.
9. current negative feedback circuit is made up of current-to-voltage converter and full-wave rectifying circuit, and its current-to-voltage converter is the mutual resistance circuit of typical balance input, by I C8The two ends of two input termination current transformer secondary winding, full-wave rectifying circuit is typical signed magnitude arithmetic(al) circuit, by amplifier I C9, I C10, resistance R 28, R 29, R 30, R 31, R 32, R 33, potentiometer W 3, switching diode D 11, D 12Constitute the output of its input termination current-to-voltage converter; Its output passes through R 2Join with the in-phase input end that compares integrating amplification circuit.
10. pulse generation and delay circuit: this circuit is made up of square-wave generator and overall pulse delay circuit, and square-wave generator is by voltage comparator I C11, resistance R 34, R 35, R 36, rectifier diode D 13, D 14Constitute.I wherein C11Inverting input pass through R 34Meet power transformer B 3An end of secondary winding; In-phase input end passes through R 35With the ground end of this device join (this device earth potential and power transformer B 3Secondary centre cap joins), I C11Same, inverting input between in parallelly insert forward and reverse two diode D 13, D 14' I C11Output be the open collector of the inner triode of voltage comparator, and pass through R 36Link with this device positive source, the ground end of the emitter of its inner triode and this device power supply joins.The overall pulse delay circuit is by XOR gate I C14Monostable circuit I C12, d type flip flop I C13And time of delay regulate resistance W 4, capacitor C 7Form the trigger end-TR of the output order steady-state circuit of its XOR gate, the output of one input end and square-wave generator and I C13D end join; Another input termination I of XOR gate C13Q, I C12Q meet I C13CP end, I C12Trigger end TR connect the power supply ground end of this device, I C12T 1, T 2Meet C between the end 7, and T 1This device of termination power supply ground end, T 2End passes through W 4Connect this device positive supply, I C13R, this device of S termination power supply ground end, I C13Q end pass through R 11With T 2Base stage join.
The making main points of this device entire circuit:
1. under oscillographic supervision, the W in the regulating impulse delay circuit 4, make the elementary B of filament transformer 1The voltage wave shape distortion minimum at two ends.
2. according to the elementary maximum current of used X-ray spot silk transformer, regulate W 3(0～10V) can cover the whole heater current working range of X-ray pipe and big slightly to make the aanalogvoltage of computer DA.Even when the analogue value of DA was maximum, its loop current can reach 110% of X-ray spot silk primary maximum current, regulate surplus so that leave some.
3. regulate W 1And W 2Make undercurrent and overcurrent voltage thresholding be transferred to required scope respectively, obtaining sending the undercurrent signal during less than the undercurrent value, when electric current sends over-current signal during greater than the mistake flow valuve when electric current.

Claims (1)

1, a kind of X line machine tube current stepless control device is characterized in that:
1. X line machine tube current stepless control device is by relatively integrating amplification circuit, undercurrent over-current signal circuit, pulse modulated circuit, linear photoelectric coupled circuit, square wave sine waveform translation circuit, full-wave rectifying circuit, matrix current adjustment circuit, current negative feedback circuit, pulse generation and delay circuit and power-supply circuit constitute;
2. compare integrating amplification circuit by operational amplifier I C1, integrating capacitor C 1, feedback resistance R 3With input resistance R 1, R 2Constitute I C1In-phase input end pass through R 2The output that connects current feedback circuit, I C1Inverting input passes through R 1The voltage that connects the DA transducer output of X line computer machine control system;
3. linear photoelectric coupled circuit is managed T by PNP 1, light-emitting diode one phototriode photoelectrical coupler G, resistance R 4, R 5, R 6, diode D 1, constitute its input T 1Base stage pass through R 4Be connected with the output that compares integrating amplification circuit, the anode of the light-emitting diode in the photoelectrical coupler meets T 1Collector electrode, negative electrode connects the low pressure negative supply of X line computer machine control system, the collector electrode of the phototriode of photoelectrical coupler connects the positive supply of this device; Emitter passes through R 6Connect this device power supply ground end;
4. undercurrent and over-current signal circuit are by voltage comparator I C2, I C3Resistance R 7, R 8, R 9, potentiometer W 1, W 2, constitute its undercurrent voltage comparator I C2In-phase input end and the inverting input of overcurrent voltage comparator respectively by input resistance R 7, R 8Join R with the output that compares integrating amplification circuit 9, W 1, W 2Form between the power supply ground end and negative supply that a voltage divider is connected across X line computer machine control system, and R 9With W 1The termination I that joins C2End of oppisite phase, W 1With W 2The termination I that joins C3In-phase end;
5. pulse modulated circuit is by triode T 2Resistance R 10, R 11Form, its emitter connects the ground end of this device power supply, and collector electrode passes through R 10Join with the emitter of the phototriode of photoelectricity coupling circuit, base stage is passed through R 11With pulse delay circuit d type flip flop I C13The Q output join;
6. square wave sine waveform translation circuit is a band pass filter, and the logical frequency of its band is identical with ac power frequency, by amplifier I C4, I C5, capacitor C 2, C 3, C 4, C 5, resistance R 12, R 13, R 14, R 15Constitute its input termination pulse modulated circuit T 2Collector electrode;
7. full-wave rectifying circuit is by I C6, I C7, switching diode D 2, D 3, resistance R 16, R 17, R 18, R 19, R 20, R 21, R 22A kind of signed magnitude arithmetic(al) circuit that constitutes, that different is feedback resistance R 21Should meet I C7One of output has terminated at matrix current adjustment circuit T 4Emitter on, the input of its input termination square wave sine waveform translation circuit;
8. matrix current adjustment circuit is by NPN triode T 3, T 4, rectifier diode D 5, D 6, D 7, D 8Voltage stabilizing didoe D 9, D 10, resistance 23, R 24, R 25, capacitor C 6, current transformer B 2, x-ray machine filament transformer B 1Elementary formation, T 3Collector electrode connect the positive supply of this device, emitter passes through R 23Join with the ground end of this device power supply, and and T 4Base stage join T 3Base stage and the output of full-wave rectifying circuit join T 4Emitter pass through R 21With I C7Inverting input join, and also pass through R 24Join D with the power supply ground end of this device 5, D 6, D 7, D 8The full-wave rectifying circuit of forming; One ac input end and current transformer B 2Elementary and filament transformer B 1An end of elementary series connection AC power; Its another ac input end directly connects the other end of AC power.Series connection inserts C between two ac input ends 6And R 25, and seal in the relative D of an anticathode 9, D 10, the cathode output end of its full-wave rectifying circuit meets T 4Collector electrode; The ground end of its cathode output end and this device power supply joins;
9. current negative feedback circuit is made up of current-to-voltage converter and full-wave rectifying circuit, and its current-to-voltage converter is the mutual resistance circuit of typical balance input, by I C8The two ends of two input termination current transformer secondary winding, full-wave rectifying circuit is typical signed magnitude arithmetic(al) circuit, by amplifier I C9, I C10, resistance R 28, R 29, R 30, R 31, R 32, R 33, potentiometer W 3, switching diode D 11, D 12Constitute, the output of its input termination current-to-voltage converter, its output passes through R 2Join with the in-phase input end that compares integrating amplification circuit;
10. pulse generation and delay circuit, this circuit is made up of square-wave generator and overall pulse delay circuit, and square-wave generator is by voltage comparator I C11, resistance R 34, R 35, R 36, rectifier diode D 13, D 14Constitute.I wherein C11Inverting input pass through R 34Meet power transformer B 3An end of secondary winding, in-phase input end passes through R 35With the ground end of this device join (this device earth potential and power transformer B 3Secondary centre cap joins), I C11Same, inverting input between in parallelly insert forward and reverse two diode D 13, D 14, I C11Output be the open collector of the inner triode of voltage comparator, and pass through R 36Link with this device positive source, the ground end of the emitter of its inner triode and this device power supply joins.The overall pulse delay circuit is by XOR gate I C14, monostable circuit I C12, d type flip flop I C13Reach and regulate resistance W time of delay 4, capacitor C 7Form the output and the I of trigger end-TR, one input end and the square-wave generator of the output order steady-state circuit of its XOR gate C13D end join; Another input termination I of XOR gate C13Q, I C12Q meet I C13CP end, I C12Trigger end TR connect the power supply ground end of this device, I C12T 1, T 2Meet C between the end 7, and T 1This device of termination power supply ground end, T 2End passes through W 4Connect this device positive supply, I C13R, this device of S termination power supply ground end, I C13Q end pass through R 11With T 2Ground level join.
CN 90103459 1990-07-13 1990-07-13 Stepless tubes current control device for x-ray instrument Expired CN1015227B (en)

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CN102612248A (en) * 2011-01-25 2012-07-25 南京普爱射线影像设备有限公司 Filament current and tube current dual-closed loop control device for X-ray machine
CN102608405B (en) * 2012-03-21 2014-12-17 刘志宏 Portable and non-intervention X-ray generator tube current measuring instrument
CN103281854B (en) * 2012-11-22 2016-04-13 南京恒瑞医疗科技有限公司 Adopt the X-ray production apparatus filament supply of high side current detection technique
WO2017107189A1 (en) * 2015-12-25 2017-06-29 华为技术有限公司 Sensor and signal processing method
CN109204287B (en) * 2018-09-30 2020-10-16 泰州科聚新材料技术研究院有限公司 New energy automobile braking control system

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