CN111082781A - Ultrasonic front-end circuit and ophthalmic B-mode ultrasonic system - Google Patents
Ultrasonic front-end circuit and ophthalmic B-mode ultrasonic system Download PDFInfo
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Abstract
The invention discloses an ultrasonic front-end circuit and an ophthalmological B ultrasonic system, which comprise a circuit board and a probe, wherein the circuit board is provided with a singlechip, an isolation protection circuit and an ultrasonic front-end circuit; the single chip microcomputer outputs a first pulse emission signal, a second pulse emission signal and a third pulse emission signal, and outputs a first pulse emission control signal, a second pulse emission control signal and a third pulse emission control signal after being isolated by an isolation protection circuit; the ultrasonic front-end circuit performs level conversion on the first pulse emission control signal, the second pulse emission control signal and the third pulse emission control signal, a positive excitation voltage and a negative excitation voltage are loaded to form a high-voltage excitation signal, and a transducer in the excitation probe generates a corresponding ultrasonic signal. The transducer is excited by adopting positive and negative excitation voltages, the excitation voltage is reduced by half, the universality and the replaceability of the device selection of a power supply and an ultrasonic front-end circuit are greatly increased, and the problem that the device selection is limited due to the fact that the existing ophthalmic B ultrasonic has only positive high voltage can be solved.
Description
Technical Field
The invention relates to the technical field of electronics, in particular to an ultrasonic front-end circuit and an ophthalmologic B ultrasonic system.
Background
The conventional ultrasonic front-end circuit of B-mode ultrasound in ophthalmology is shown in fig. 1, where + HV is the transmitted excitation voltage, MOS transistor is the electronic switch for transmission control, and the capacitor is a high-voltage capacitor. The ophthalmic B ultrasonic emission control unit gives out a pulse emission signal to control the on-off of the MOS tube, and when the MOS tube is switched on, an excitation voltage is loaded on the energy converter TR, and an ultrasonic wave is generated by a piezoelectric effect, so that one-time ultrasonic emission is completed.
However, since the probe of the ophthalmic B-mode ultrasonic is a single-crystal transducer with a diameter of 9mm, the static capacitance is large, a high excitation voltage is required, and the theoretical requirement is 200V. The prior art adopts a single excitation high voltage and only a positive high voltage, which requires that all devices used by a power supply and an ultrasonic front-end circuit can bear the high voltage, obviously, the high voltage is far greater than the human body safety voltage, and the design complexity of the circuit and a machine is greatly improved. The common power supply (the common B-mode power supply does not exceed 100V) on the market can not be used universally, needs to be designed and purchased independently, and has relatively high cost. Meanwhile, the power consumption of the ultrasonic front-end circuit is relatively large, the service time and the service life of a battery of a portable machine (namely, an ophthalmological B ultrasonic device) are influenced, and the heat dissipation of the machine is more complicated due to the high power consumption.
In addition, because high voltage is needed, the MOS tube and other devices need to be high voltage resistant, the replaceability of the devices is small, and the selection is limited. Since the on and off of the MOS transistor takes time, the higher the voltage is, the longer the time is, which causes deformation of the emitted ultrasonic wave and affects the reliability of the ultrasonic wave. Since the high-voltage ultrasonic front-end circuit and the highly sensitive receiving circuit are connected together, the switch of such high voltage has a great influence on the receiving circuit, so that the design of the isolation circuit is complicated. Due to the adoption of a single MOS tube, the control can not be carried out after the emission, so that the ringing response on the transducer is very large, and the quality and the resolution of the B ultrasonic image can be seriously damaged.
Thus, the prior art has yet to be improved and enhanced.
Disclosure of Invention
In view of the above-mentioned shortcomings in the prior art, the present invention is directed to an ultrasound front-end circuit and an ophthalmic B-mode system, so as to solve the problem that the device selection is limited because the excitation high voltage of the existing ophthalmic B-mode system is only a positive high voltage.
In order to achieve the purpose, the invention adopts the following technical scheme:
an ultrasonic front-end circuit, connecting probe and isolation protection circuit, it includes level conversion module, high-voltage excitation module and oscillation starting matching module: the high-voltage excitation module is connected with the level conversion module and the oscillation starting matching module, the level conversion module is connected with the isolation protection circuit, and the oscillation starting matching module is connected with the probe;
the level conversion module performs level conversion on the first pulse emission control signal, the second pulse emission control signal and the third pulse emission control signal and then outputs a first pulse emission driving signal, a second pulse emission driving signal and a third pulse emission driving signal; when the high-voltage excitation module detects that the first pulse emission driving signal and the second pulse emission driving signal are effective, positive and negative excitation voltages are correspondingly loaded to form a high-voltage excitation signal, and when the high-voltage excitation module detects that the third pulse emission driving signal is effective, the excitation voltage is discharged to the ground; and the oscillation starting matching module performs oscillation starting matching on the high-voltage excitation signal and outputs the high-voltage excitation signal to the probe.
In the ultrasonic front-end circuit, the level conversion module comprises a first driving chip, a second driving chip, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor and a first magnetic bead;
the INA pin and the INB pin of the first driving chip are both connected with an isolation protection circuit; a VCC pin of the first driving chip is connected with one end of the fourth capacitor, one end of the first magnetic bead and one end of the third capacitor; the OUTA pin and the OUTB pin of the first driving chip are both connected with the high-voltage excitation module; the VCC pin of the second driving chip is connected with one end of the fifth capacitor and the VCC pin of the first driving chip; the other end of the first magnetic bead is connected with the anode of the first capacitor, one end of the second capacitor and the power supply end; the other end of the fifth capacitor is connected with the cathode of the first capacitor, the other end of the second capacitor and the ground; the INA pin of the second driving chip is connected with the INB pin and the isolation protection circuit, and the OUTA pin of the second driving chip is connected with the OUTB pin and the high-voltage excitation module; the GND pin of the first driving chip, the GND pin of the second driving chip, the other end of the third capacitor and the other end of the fourth capacitor are all grounded.
In the ultrasonic front-end circuit, the high-voltage excitation module comprises a first electronic switch, a second electronic switch, a third electronic switch, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth capacitor, a seventh capacitor, a first resistor and a second resistor;
the grid electrode of the first electronic switch is connected with the positive electrode of the first diode and one end of a sixth capacitor, the other end of the sixth capacitor is connected with an OUTA pin of the first driving chip through a first resistor, and the source electrode of the first electronic switch is connected with the negative high-voltage end and the negative electrode of the first diode; the drain electrode of the first electronic switch is connected with the source electrode of the second electronic switch, one end of the third diode, the anode of the fourth diode and the cathode of the fifth diode; the other end of the third diode is connected with the oscillation starting matching module, the grid electrode of the second electronic switch is connected with the anode of the second diode and one end of a seventh capacitor, the other end of the seventh capacitor is connected with the OUTB pin of the first driving chip through a second resistor, the drain electrode of the second electronic switch is connected with the positive high-voltage end and the cathode of the second diode, the cathode of the fourth diode is connected with the anode of the fifth diode and the drain electrode of the third electronic switch, the grid electrode of the third electronic switch is connected with the OUTA pin and the OUTB pin of the second driving chip, and the source electrode of the third electronic switch is grounded.
In the ultrasonic front-end circuit, the high-voltage excitation module further comprises a third resistor, a fourth resistor, a fifth resistor and a sixth resistor;
one end of the third resistor is connected with the anode of the first diode and one end of the sixth capacitor, the other end of the third resistor is connected with the negative high-voltage end and the cathode of the first diode, one end of the fourth resistor is connected with the anode of the second diode and one end of the seventh capacitor, the other end of the fourth resistor is connected with the positive high-voltage end and the cathode of the second diode, the fifth resistor is connected between the negative high-voltage end and the source electrode of the first electronic switch, and the sixth resistor is connected between the positive high-voltage end and the drain electrode of the second electronic switch.
In the ultrasonic front-end circuit, the high-voltage excitation module further comprises an eighth capacitor, a ninth capacitor, a tenth capacitor and an eleventh capacitor;
the negative electrode of the eighth capacitor is connected with one end of the ninth capacitor and the negative high-voltage end, and the positive electrode of the tenth capacitor is connected with one end of the eleventh capacitor and the positive high-voltage end; and the anode of the eighth capacitor, the other end of the ninth capacitor, the cathode of the tenth capacitor and the other end of the eleventh capacitor are all grounded.
In the ultrasonic front-end circuit, the oscillation starting matching module comprises a first inductor and a seventh resistor, one end of the first inductor is connected with the other end of the third diode and one end of the seventh resistor, the other end of the first inductor is connected with one end of the transducer, and the other end of the seventh resistor and the other end of the transducer are grounded.
An ophthalmic B-ultrasonic system comprises a circuit board and a probe, wherein the circuit board is provided with a singlechip, an isolation protection circuit and an ultrasonic front-end circuit; the isolation protection circuit is connected with the singlechip and the ultrasonic front-end circuit, and the ultrasonic front-end circuit is connected with the probe;
the single chip microcomputer outputs a first pulse emission signal, a second pulse emission signal and a third pulse emission signal, and outputs a first pulse emission control signal, a second pulse emission control signal and a third pulse emission control signal after being isolated by an isolation protection circuit; the ultrasonic front-end circuit performs level conversion on the first pulse emission control signal, the second pulse emission control signal and the third pulse emission control signal, a positive excitation voltage and a negative excitation voltage are loaded to form a high-voltage excitation signal, and a transducer in the excitation probe generates a corresponding ultrasonic signal.
In the ophthalmic B-mode ultrasonic system, the isolation protection circuit comprises an isolation chip, a second magnetic bead, a twelfth capacitor and a thirteenth capacitor;
the pin B1 of the isolation chip is connected with the pin B2 and the singlechip, the pin B4 of the isolation chip is connected with the pin B5 and the singlechip,the B7 pin of the isolation chip is connected with the B8 pin and the singlechip; an A1 pin of the isolation chip is connected with an A2 pin and the ultrasonic front-end circuit, an A4 pin of the isolation chip is connected with an A5 pin and the ultrasonic front-end circuit, an A7 pin of the isolation chip is connected with an A8 pin and the ultrasonic front-end circuit, a VDD pin of the isolation chip is connected with one end of a second magnetic bead and one end of a twelfth capacitor, and the other end of the second magnetic bead is connected with a power supply end and one end of a thirteenth capacitor; the other end of the twelfth capacitor, the other end of the thirteenth capacitor, a DIR pin of the isolation chip and
the pins are all grounded.
Compared with the prior art, the ultrasonic front-end circuit and the ophthalmic B-mode ultrasonic system provided by the invention comprise a circuit board and a probe, wherein the circuit board is provided with a single chip microcomputer, an isolation protection circuit and an ultrasonic front-end circuit; the isolation protection circuit is connected with the singlechip and the ultrasonic front-end circuit, and the ultrasonic front-end circuit is connected with the probe; the single chip microcomputer outputs a first pulse emission signal, a second pulse emission signal and a third pulse emission signal, and outputs a first pulse emission control signal, a second pulse emission control signal and a third pulse emission control signal after being isolated by an isolation protection circuit; the ultrasonic front-end circuit performs level conversion on the first pulse emission control signal, the second pulse emission control signal and the third pulse emission control signal, a positive excitation voltage and a negative excitation voltage are loaded to form a high-voltage excitation signal, and a transducer in the excitation probe generates a corresponding ultrasonic signal. Due to the fact that the transducer is excited by positive and negative excitation voltages, the excitation voltage is reduced by half, universality and replaceability of device selection of a power supply and an ultrasonic front-end circuit are greatly improved, and the problem that device selection is limited due to the fact that only positive high voltage exists in excitation high voltage of the existing ophthalmic B ultrasonic can be solved.
Drawings
Fig. 1 is a circuit diagram of an ultrasound front-end circuit of a conventional ophthalmic B-mode ultrasound.
Fig. 2 is a block diagram of an ophthalmic B-mode ultrasound system according to the present invention.
Fig. 3 is a circuit diagram of an ultrasound front-end circuit provided by the present invention.
Fig. 4 is a circuit diagram of an isolation protection circuit provided by the present invention.
Fig. 5 is a waveform diagram of a transmission control timing provided by the present invention.
Fig. 6 is a waveform diagram of duty cycle control provided by the present invention.
Detailed Description
The invention provides an ultrasonic front-end circuit and an ophthalmic B-mode ultrasonic system. In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 2, the ophthalmic B-mode ultrasound system according to the embodiment of the present invention includes a circuit board and a probe 40, wherein the circuit board is provided with an ultrasound front-end circuit 10, a single-chip microcomputer 20 and an isolation protection circuit 30; the isolation protection circuit 30 is connected with the single chip microcomputer 20 and the ultrasonic front-end circuit 10, and the ultrasonic front-end circuit 10 is connected with the probe 40; the single chip microcomputer 20 outputs a first pulse emission signal PES11, a second pulse emission signal PES12 and a third pulse emission signal PES13 of 3.3V, and outputs a first pulse emission control signal PES21, a second pulse emission control signal PES22 and a third pulse emission control signal PES23 of 5V after being isolated by the isolation protection circuit 30; the ultrasonic front-end circuit 10 performs level conversion on the first pulse emission control signal PES21, the second pulse emission control signal PES22 and the third pulse emission control signal PES23, loads positive and negative excitation voltages to form a high-voltage excitation signal HVES, and excites the transducer in the probe 40 to generate corresponding ultrasonic signals.
It should be understood that the single chip microcomputer 20 is a prior art, and other circuits are also disposed on the circuit board, and only the circuits related to the present embodiment are described herein. The ultrasonic front-end circuit 10 is not limited to ophthalmic B-mode ultrasound, and can be used as long as a fan-scan type B-mode ultrasound using a single crystal transducer is used.
Referring to fig. 3, the ultrasound front-end circuit 10 includes a level conversion module 100, a high-voltage excitation module 200, and an oscillation starting matching module 300. The high-voltage excitation module 200 is connected with the level conversion module 100 and the oscillation starting matching module 300, the level conversion module 100 is connected with the isolation protection circuit 30, and the oscillation starting matching module 300 is connected with the probe 40; the level shift module 100 performs level shift on the first, second and third pulse emission control signals PES21, PES22 and PES23 of 5V, and outputs the first, second and third pulse emission drive signals PES31, PES32 and PES33 of 12V; the high-voltage excitation module 200 detects that the first pulse emission driving signal PES31 and the second pulse emission driving signal PES32 are effective and correspondingly load positive and negative excitation voltages to form a high-voltage excitation signal HVES, and also detects that the third pulse emission driving signal PES33 is effective and discharges the excitation voltages and energy of high-voltage oscillation generated when the excitation voltages and the energy of the high-voltage oscillation are applied to the transducer to the ground; the oscillation starting matching module 300 performs oscillation starting matching on the high-voltage excitation signal HVES and outputs the result to the probe 40.
The level shift module 100 includes a first driving chip U1, a second driving chip U2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a first magnetic bead L1; the INA pin and the INB pin of the first driving chip U1 are both connected with the isolation protection circuit 30; a VCC pin of the first driving chip U1 is connected with one end of the fourth capacitor C4, one end of the first magnetic bead L1 and one end of the third capacitor C3; the OUTA pin and the OUTB pin of the first driving chip U1 are both connected with the high-voltage excitation module 200; the VCC pin of the second driving chip U2 is connected with one end of the fifth capacitor C5 and the VCC pin of the first driving chip U1; the other end of the first magnetic bead L1 is connected to the positive electrode of the first capacitor C1, one end of the second capacitor C2, and the power supply terminal (input power supply voltage VCC); the other end of the fifth capacitor C5 is connected with the cathode of the first capacitor C1, the other end of the second capacitor C2 and the ground; the INA pin of the second driving chip U2 is connected with the INB pin and the isolation protection circuit 30, and the OUTA pin of the second driving chip U2 is connected with the OUTB pin and the high-voltage excitation module 200; the GND pin of the first driving chip U1, the GND pin of the second driving chip U2, the other end of the third capacitor C3 and the other end of the fourth capacitor C4 are all grounded.
The models of the first driving chip U1 and the second driving chip U2 are UCC37323 preferably; the high-voltage excitation module mainly plays a role in isolation driving, the first pulse emission control signal PES21 and the second pulse emission control signal PES22 of 5V are boosted through the U1 and then output a first pulse emission driving signal PES31 and a second pulse emission driving signal PES32 of 12V to the high-voltage excitation module 200, and the third pulse emission control signal PES23 of 5V is boosted through the U2 and output a third pulse emission driving signal PES33 of 12V to the high-voltage excitation module 200. Therefore, the low-voltage single chip microcomputer 20 (namely, the MCU is a sensitive high-value device generally) can be protected, the phenomenon that the transmitting high voltage flows back into the single chip microcomputer 20 due to accidental faults of the transmitting end, the single chip microcomputer 20 is damaged, even the whole machine is damaged is avoided, and safety accidents are avoided. The output waveforms of U1 and U2 are the same frequency and width waveforms as the pulse transmission signals PES 11-PES 13 in this embodiment.
The first capacitor C1 is a tantalum capacitor with the capacitance value of preferably 220uF, the second capacitor C2 is a low ESR laminated ceramic capacitor with the capacitance value of 22uF, and C1 and C2 jointly form a power supply bypass filter circuit of the level conversion module 100; the first magnetic bead L1 and the third capacitor C3 form an LC filter circuit, and the first magnetic bead L1 can adopt 0603 magnetic beads 601; the fourth capacitor C4 is the decoupling capacitor of U1, and the capacitance value is preferably 0.1 uF; the fifth capacitor C5 is a decoupling capacitor of U1, and its capacitance value is preferably 0.1 uF.
It should be understood that in the present embodiment, the excitation waveform of the subsequent stage of the electronic switch (i.e., Q1-Q3) is positive and negative pulses, and in order to generate this excitation waveform, the MOS transistors of U1 and U2 may have different alternatives, for example, U1 and U2 may use UCC37323 (dual-path signal inversion), UCC37324 (dual-path non-inversion), or UCC37325 (single-path inversion) in UCC3732X series, which cooperate with the pulse emission control signals PES 21-PES 23 to generate corresponding alternatives. The U1 and U2 may be the same or different in type.
The high-voltage excitation module 200 comprises a first electronic switch Q1, a second electronic switch Q2, a third electronic switch Q3, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth capacitor C6, a seventh capacitor C7, a first resistor R1 and a second resistor R2; the grid electrode of the first electronic switch Q1 is connected with the positive electrode of a first diode D1 and one end of a sixth capacitor C6, the other end of the sixth capacitor C6 is connected with an OUTA pin of a first driving chip U1 through a first resistor R1, and the source electrode of the first electronic switch Q1 is connected with a negative high-voltage end-HV and the negative electrode of the first diode D1; the drain of the first electronic switch Q1 is connected to the source of the second electronic switch Q2, one end of the third diode D3, the anode of the fourth diode D4 and the cathode of the fifth diode D5; the other end of the third diode D3 is connected to the start-up matching module 300, the gate of the second electronic switch Q2 is connected to the anode of the second diode D2 and one end of the seventh capacitor C7, the other end of the seventh capacitor C7 is connected to the OUTB pin of the first driver chip U1 through the second resistor R2, the drain of the second electronic switch Q2 is connected to the positive high-voltage terminal + HV and the cathode of the second diode D2, the cathode of the fourth diode D4 is connected to the anode of the fifth diode D5 and the drain of the third electronic switch Q3, the gate of the third electronic switch Q3 is connected to the OUTA pin and the OUTB pin of the second driver chip U2, and the source of the third electronic switch Q3 is grounded.
The first electronic switch Q1 and the third electronic switch Q3 may adopt NMOS transistors, and the second electronic switch Q2 may adopt PMOS transistors; the on-off states of the Q1, the Q2 and the Q3 are respectively controlled by a first pulse emission driving signal PES31, a second pulse emission driving signal PES32 and a third pulse emission driving signal PES33, and when the Q1 and the Q2 are conducted, corresponding positive excitation voltage (high voltage) and negative excitation voltage are generated into high-voltage pulse emission signals which are loaded on a transducer TR of the probe through the oscillation starting matching module 300.
The first diode D1 and the second diode D2 are bleeder diodes, and are used for rapidly releasing PES31 and PES32 to ensure the effectiveness of the on-off of the electronic switch, so as to ensure the effective width of the excitation voltage and the symmetry of the positive excitation voltage and the negative excitation voltage, which are very important in the fast emission process, the on-off of the electronic switch has time delay, and the problem that the accuracy of the excitation voltage is seriously influenced because the opening signal of the next electronic switch is loaded when the last electronic switch is closed can be solved through D1 and D2. The D4 and D5 are used for clamping the ground after the transmission is finished, so that the energy generated by the oscillation of the transducer is released to the ground through D4, D5 and Q3 after passing through D3, the ringing response of the transducer end can be effectively eliminated, various clutter signals are led into the ground, the high-amplitude signal of the ground circuit is effectively prevented from being interfered back to the transmission circuit, and the system interference is reduced. The third diode D3 is a bidirectional diode, which is the first stage of simple isolation between the transmitted signal and the echo signal, so that the echo signal enters the signal receiving circuit as much as possible, and the germanium tube LBAT54SLT1G with the pressure difference of 0.2V is selected. R1 and R2 are equal in resistance, preferably 5 Ω or less, for eliminating spikes in PES31 and PES 32. The capacitance values of C6 and C7 are equal, and a high-voltage capacitor is adopted, such as the specification of 0.1 UF/450V.
Referring to fig. 5, when the first pulse-emission driving signal PES31 is asserted and is at a high level, Q1 is turned on, and a negative driving voltage is applied; when the second pulse emission driving signal PES32 is active and is at low level, Q2 is turned on, and a positive excitation voltage is applied; at the same time, the third burst drive signal PES33 is inactive, low placing Q3 in an off state and an excitation voltage is applied to the transducer. When the third burst drive signal PES33 is active high, the excitation voltage is discharged to ground due to the Q3 being conductive and does not load the transducer regardless of the state of the first and second burst drive signals PES31 and PES 32.
The active time width of the first and second burst drive signals PES31 and PES32 is equal to the inactive time width of the third burst drive signal PES33, and this time dimension can be adjusted according to the difference of the probe emission frequency.
Preferably, the high voltage excitation module 200 further includes a third resistor R3, a fourth resistor R4, a fifth resistor R5 and a sixth resistor R6; one end of the third resistor R3 is connected with the positive electrode of the first diode D1 and one end of the sixth capacitor C6, the other end of the third resistor R3 is connected with the negative high-voltage end-HV and the negative electrode of the first diode D1, one end of the fourth resistor R4 is connected with the positive electrode of the second diode D2 and one end of the seventh capacitor C7, the other end of the fourth resistor R4 is connected with the positive high-voltage end + HV and the negative electrode of the second diode D2, the fifth resistor R5 is connected between the negative high-voltage end-HV and the source electrode of the first electronic switch Q1, and the sixth resistor R6 is connected between the positive high-voltage end + HV and the drain electrode of the second electronic switch Q2. By pulling up R3 and R5, R4 and R6, the electronic switch can be prevented from misoperation when the electronic switch is turned on or is interfered.
Preferably, the high voltage excitation module 200 further includes an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10 and an eleventh capacitor C11; the negative electrode of the eighth capacitor C8 is connected with one end of the ninth capacitor C9 and the negative high-voltage end-HV, and the positive electrode of the tenth capacitor C10 is connected with one end of the eleventh capacitor C11 and the positive high-voltage end + HV; the anode of the eighth capacitor C8, the other end of the ninth capacitor C9, the cathode of the tenth capacitor C10 and the other end of the eleventh capacitor C11 are all grounded. C8 and C9 are energy storage filter capacitors for negative excitation high voltage (negative high voltage terminal-HV provided), and C10 and C11 are energy storage filter capacitors for positive excitation high voltage (positive high voltage terminal + HV provided).
The oscillation starting matching module 300 comprises a first inductor L2 and a seventh resistor R7, one end of the first inductor L2 is connected with the other end of a third diode D3 and one end of the seventh resistor R7, the other end of the first inductor L2 is connected with one end of a transducer TR, and the other end of the seventh resistor R7 and the other end of the transducer TR are both grounded.
The first inductor L2 is generally connected in parallel to the ground in the existing circuit, and forms an auxiliary oscillation circuit of the transducer in cooperation with a resistor, and the embodiment is connected in series to the ultrasonic front-end circuit instead, which is tested to be more beneficial to shaping the transmission waveform. Given that the static capacitance of the transducer is large and the inductance of the first inductor L2 cannot be too large, 0.12uH is chosen to match the 10M probe in this embodiment.
Referring to fig. 4, the isolation protection circuit 30 includes an isolation chip U3, a second magnetic bead L3, a twelfth capacitor C12, and a thirteenth capacitor C13; a pin B1 of the isolation chip U3 is connected with a pin B2 and the singlechip 20, a pin B4 of the isolation chip U3 is connected with a pin B5 and the singlechip 20, and a pin B7 of the isolation chip U3 is connected with a pin B8 and the singlechip 20; a pin A1 of the isolation chip U3 is connected with a pin A2 and an pin INA of the second drive chip U2, a pin A4 of the isolation chip U3 is connected with a pin A5 and a pin INB of the first drive chip U1, a pin A7 of the isolation chip U3 is connected with a pin A8 and a pin INA of the first drive chip U1, a pin VDD of the isolation chip U3 is connected with one end of the second magnetic bead L3 and one end of the twelfth capacitor C12, and the other end of the second magnetic bead L3 is connected with a power supply terminal (input power supply voltage VDD) and one end of the thirteenth capacitor C13; the other end of the twelfth capacitor C12, the other end of the thirteenth capacitor C13, and the DI of the isolation chip U3R foot and
the pins are all grounded.
The type of the isolation chip U3 is preferably MC74VHC245DT, C13 mainly has an energy storage filtering effect, L3 and C12 form an LC filtering circuit, and L3 uses 0603 magnetic beads 601. The isolation chip U3 isolates each pulse emission control signal output by the single chip microcomputer without changing the function of the signal, so that the pulse emission control signals PES 11-PES 33 are also output by the isolation chip U3.
The single chip microcomputer 20 is in the prior art, and the isolation chip U3 is specifically connected with which pin of the single chip microcomputer is also in the prior art, and only three transmitting pulse signals output by the single chip microcomputer are used here.
Referring to fig. 6, the single chip microcomputer 20 may further adjust duty ratios of the first pulse transmission signal PES11, the second pulse transmission signal PES12, and the third pulse transmission signal PES 13. For example, a duty cycle of 60% (for example only, adjustable as needed, the adjustment range theoretically being 0 to 100%); the dotted line is the excitation waveform at a duty cycle of 60%, and the solid line is the excitation waveform at a duty cycle of 100%. The excitation voltage with the duty ratio of 100% is strongest, the signal is strongest at the moment, but the signal saturation of the leading end B is easily caused, and the most important reason is that the transducer generates heat to a certain extent, the examination experience of a patient is not good, and the excitation waveform of the transducer is damaged by long-time diagnosis; when the duty ratio is properly adjusted, the problem of probe heating is solved firstly, the ideal emission waveform is a pulse waveform, the adjustment of the duty ratio does not influence the peak-to-peak value of the excitation high voltage, and the effective emission energy is more concentrated, so that a better excitation waveform can be generated, the image is finer and finer, the details of the image are richer, the diagnosis is more convenient, and the quality of the later-stage image is improved. Meanwhile, the heating of the transducer is greatly reduced, the temperature rise control of the probe is greatly simple and convenient, the aging and performance attenuation of the transducer are greatly slowed down, and the service life of the whole machine is prolonged.
In conclusion, in the ophthalmic B-mode ultrasonic system provided by the invention, the transducer is de-excited by adopting positive and negative excitation voltage (a pulse high voltage), the emission waveform is controlled by 3 electronic switches, the excitation pulse is more regular and symmetrical, the duty ratio of the emission pulse is adjustable, and the emission energy is more effectively concentrated; in addition, due to the fact that positive and negative pulses are transmitted, excitation voltage is reduced by half, universality and replaceability of component selection of a power supply and an ultrasonic front-end circuit are greatly increased, purchasing and maintenance are greatly simple and convenient, and corresponding various costs are greatly reduced; the on-off of the electronic switch is controlled by the first pulse emission driving signal and the second pulse emission driving signal to realize corresponding positive and negative high-voltage emission, so that the positive and negative pulses are symmetrical and less deformed, the output noise is greatly reduced, the signal-to-noise ratio of the system is greatly improved, and the quality and the resolution of a B-mode ultrasonic image are also obviously improved. The third pulse emission control signal is clamped to the ground immediately after the emission is finished, so that the ringing response caused by the on-off time delay of the electronic switch is effectively eliminated, the clutter interference of the system is further reduced, and the isolation of the ultrasonic front-end circuit and the receiving circuit is simple and effective.
The division of the functional modules is only used for illustration, and in practical applications, the functions may be distributed by different functional modules according to needs, that is, the functions may be divided into different functional modules to complete all or part of the functions described above.
It should be understood that equivalents and modifications of the technical solution and inventive concept thereof may occur to those skilled in the art, and all such modifications and alterations should fall within the scope of the appended claims.
Claims (8)
1. The utility model provides an ultrasonic front-end circuit, connection probe and isolation protection circuit which characterized in that, includes level conversion module, high-voltage excitation module and the matching module that starts to vibrate: the high-voltage excitation module is connected with the level conversion module and the oscillation starting matching module, the level conversion module is connected with the isolation protection circuit, and the oscillation starting matching module is connected with the probe;
the level conversion module performs level conversion on the first pulse emission control signal, the second pulse emission control signal and the third pulse emission control signal and then outputs a first pulse emission driving signal, a second pulse emission driving signal and a third pulse emission driving signal; when the high-voltage excitation module detects that the first pulse emission driving signal and the second pulse emission driving signal are effective, positive and negative excitation voltages are correspondingly loaded to form a high-voltage excitation signal, and when the high-voltage excitation module detects that the third pulse emission driving signal is effective, the excitation voltage is discharged to the ground; and the oscillation starting matching module performs oscillation starting matching on the high-voltage excitation signal and outputs the high-voltage excitation signal to the probe.
2. The ultrasound front-end circuit of claim 1, wherein the level conversion module comprises a first driver chip, a second driver chip, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, and a first magnetic bead;
the INA pin and the INB pin of the first driving chip are both connected with an isolation protection circuit; a VCC pin of the first driving chip is connected with one end of the fourth capacitor, one end of the first magnetic bead and one end of the third capacitor; the OUTA pin and the OUTB pin of the first driving chip are both connected with the high-voltage excitation module; the VCC pin of the second driving chip is connected with one end of the fifth capacitor and the VCC pin of the first driving chip; the other end of the first magnetic bead is connected with the anode of the first capacitor, one end of the second capacitor and the power supply end; the other end of the fifth capacitor is connected with the cathode of the first capacitor, the other end of the second capacitor and the ground; the INA pin of the second driving chip is connected with the INB pin and the isolation protection circuit, and the OUTA pin of the second driving chip is connected with the OUTB pin and the high-voltage excitation module; the GND pin of the first driving chip, the GND pin of the second driving chip, the other end of the third capacitor and the other end of the fourth capacitor are all grounded.
3. The ultrasound front-end circuit of claim 2, wherein the high voltage excitation module comprises a first electronic switch, a second electronic switch, a third electronic switch, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth capacitor, a seventh capacitor, a first resistor, and a second resistor;
the grid electrode of the first electronic switch is connected with the positive electrode of the first diode and one end of a sixth capacitor, the other end of the sixth capacitor is connected with an OUTA pin of the first driving chip through a first resistor, and the source electrode of the first electronic switch is connected with the negative high-voltage end and the negative electrode of the first diode; the drain electrode of the first electronic switch is connected with the source electrode of the second electronic switch, one end of the third diode, the anode of the fourth diode and the cathode of the fifth diode; the other end of the third diode is connected with the oscillation starting matching module, the grid electrode of the second electronic switch is connected with the anode of the second diode and one end of a seventh capacitor, the other end of the seventh capacitor is connected with the OUTB pin of the first driving chip through a second resistor, the drain electrode of the second electronic switch is connected with the positive high-voltage end and the cathode of the second diode, the cathode of the fourth diode is connected with the anode of the fifth diode and the drain electrode of the third electronic switch, the grid electrode of the third electronic switch is connected with the OUTA pin and the OUTB pin of the second driving chip, and the source electrode of the third electronic switch is grounded.
4. The ultrasound front-end circuit of claim 3, wherein the high voltage excitation module further comprises a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor;
one end of the third resistor is connected with the anode of the first diode and one end of the sixth capacitor, the other end of the third resistor is connected with the negative high-voltage end and the cathode of the first diode, one end of the fourth resistor is connected with the anode of the second diode and one end of the seventh capacitor, the other end of the fourth resistor is connected with the positive high-voltage end and the cathode of the second diode, the fifth resistor is connected between the negative high-voltage end and the source electrode of the first electronic switch, and the sixth resistor is connected between the positive high-voltage end and the drain electrode of the second electronic switch.
5. The ultrasound front-end circuit of claim 4, wherein the high-voltage excitation module further comprises an eighth capacitor, a ninth capacitor, a tenth capacitor, and an eleventh capacitor;
the negative electrode of the eighth capacitor is connected with one end of the ninth capacitor and the negative high-voltage end, and the positive electrode of the tenth capacitor is connected with one end of the eleventh capacitor and the positive high-voltage end; and the anode of the eighth capacitor, the other end of the ninth capacitor, the cathode of the tenth capacitor and the other end of the eleventh capacitor are all grounded.
6. The ultrasonic front-end circuit of claim 5, wherein the oscillation starting matching module comprises a first inductor and a seventh resistor, one end of the first inductor is connected with the other end of the third diode and one end of the seventh resistor, the other end of the first inductor is connected with one end of the transducer, and the other end of the seventh resistor and the other end of the transducer are both grounded.
7. An ophthalmic B-mode ultrasound system comprising a circuit board and a probe, wherein the circuit board is provided with a single chip microcomputer, an isolation protection circuit and an ultrasound front-end circuit according to any one of claims 1 to 6; the isolation protection circuit is connected with the singlechip and the ultrasonic front-end circuit, and the ultrasonic front-end circuit is connected with the probe;
the single chip microcomputer outputs a first pulse emission signal, a second pulse emission signal and a third pulse emission signal, and outputs a first pulse emission control signal, a second pulse emission control signal and a third pulse emission control signal after being isolated by an isolation protection circuit; the ultrasonic front-end circuit performs level conversion on the first pulse emission control signal, the second pulse emission control signal and the third pulse emission control signal, a positive excitation voltage and a negative excitation voltage are loaded to form a high-voltage excitation signal, and a transducer in the excitation probe generates a corresponding ultrasonic signal.
8. The ophthalmic B-mode ultrasound system of claim 7, wherein the isolation protection circuit comprises an isolation chip, a second magnetic bead, a twelfth capacitor, and a thirteenth capacitor;
the B1 pin of the isolation chip is connected with the B2 pin and the single chip microcomputer, the B4 pin of the isolation chip is connected with the B5 pin and the single chip microcomputer, and the B7 pin of the isolation chip is connected with the B8 pin and the single chip microcomputer; an A1 pin of the isolation chip is connected with an A2 pin and the ultrasonic front-end circuit, an A4 pin of the isolation chip is connected with an A5 pin and the ultrasonic front-end circuit, an A7 pin of the isolation chip is connected with an A8 pin and the ultrasonic front-end circuit, a VDD pin of the isolation chip is connected with one end of a second magnetic bead and one end of a twelfth capacitor, and the other end of the second magnetic bead is connected with a power supply end and one end of a thirteenth capacitor; the other end of the twelfth capacitor, thirteenthThe other end of the capacitor, the DIR pin of the isolation chip and
the pins are all grounded.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010118434.7A CN111082781A (en) | 2020-02-26 | 2020-02-26 | Ultrasonic front-end circuit and ophthalmic B-mode ultrasonic system |
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| CN202010118434.7A CN111082781A (en) | 2020-02-26 | 2020-02-26 | Ultrasonic front-end circuit and ophthalmic B-mode ultrasonic system |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112532223A (en) * | 2020-12-24 | 2021-03-19 | 深圳市威尔德医疗电子有限公司 | Real-time synchronous imaging probe circuit and B-ultrasonic equipment |
| CN112729431A (en) * | 2020-12-31 | 2021-04-30 | 浙江正泰燃气装备有限公司 | Ultrasonic wave measurement sensor signal detection circuitry |
| CN116509454A (en) * | 2023-07-05 | 2023-08-01 | 深圳市威尔德医疗电子有限公司 | Full digital A/B ultrasonic device for eyes |
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2020
- 2020-02-26 CN CN202010118434.7A patent/CN111082781A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112532223A (en) * | 2020-12-24 | 2021-03-19 | 深圳市威尔德医疗电子有限公司 | Real-time synchronous imaging probe circuit and B-ultrasonic equipment |
| CN112729431A (en) * | 2020-12-31 | 2021-04-30 | 浙江正泰燃气装备有限公司 | Ultrasonic wave measurement sensor signal detection circuitry |
| CN116509454A (en) * | 2023-07-05 | 2023-08-01 | 深圳市威尔德医疗电子有限公司 | Full digital A/B ultrasonic device for eyes |
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