CN205068041U - Control circuit of supersound PFT appearance - Google Patents

Abstract

The utility model relates to a medical science ultrasonic instrument technical field specifically discloses a control circuit of supersound PFT appearance, including MCU module, GP22 chip, the MCU module disposes with the GP22 chip, the GP22 chip is equipped with four pins, is FIRE UP pin, STOP1 pin, FIRE DOWN pin, STOP2 pin respectively, the FIREUP pin is connected with pulse generating circuit 1, and warp probe 1 is connected with change over switch K1, change over switch K1 is connected with amplifier circuit 1's input through a blocking capacitance, is connected with the STOP1 pin behind amplifier circuit 1, the FIREDOWN pin is connected with pulse generating circuit 2, and warp probe 2 is connected with change over switch K2, change over switch K2 is connected with amplifier circuit 2's input through a blocking capacitance, is connected with the STOP2 pin behind amplifier circuit 2, the MCU module is equipped with two IO pins, is connected with change over switch K1, K2's control end respectively. Hardware cost reduction has saved software and has compile, has shortened development period, has reduced the listing time.

Description

A kind of control circuit of ultrasonic lung function instrument

Technical field

The utility model relates to medical ultrasonic Instrument technology field, refers to a kind of control circuit of ultrasonic lung function instrument especially.

Background technology

Ultrasonic lung function instrument, by measuring ultrasonic pulse signal from different directions through the mistiming after the gas of tested person's breathing, converses the actual flow velocity of gas, thus draws the indices parameter of tested person's pulmonary function.The ultrasonic lung function instrument of current main-stream all adopts FPGA or CPLD to control and computing circuit as core.Because reception waveform is analog quantity, need first to be converted to the digital signal consistent with the IO level of FPGA or CPLD before entering FPGA or CPLD.The method of conversion has two kinds, and one adopts comparer, by zero passage detection, analog quantity is converted into digital quantity; Another kind adopts AD conversion chip, and signal and noise are first converted into digital quantity, by algorithm decision signal and noise in FPGA or CPLD.A kind of front method requires that signal to noise ratio (S/N ratio) is very high, rear a kind of before comparer, does not require there was too high signal to noise ratio (S/N ratio) before AD conversion.The hardware cost of these two kinds of methods is all higher, and writing of software is also comparatively complicated.

Utility model content

The purpose of this utility model is to provide a kind of control circuit of ultrasonic lung function instrument, saves hardware cost, eliminates again software programming work, shortens the construction cycle, reduce Time To Market.

To achieve these goals, the utility model have employed following technical scheme: a kind of control circuit of ultrasonic lung function instrument, comprises MCU module, controls and the GP22 chip of computing for core;

Described MCU module and GP22 chip are configured;

Described GP22 chip is provided with four pins, is respectively FIREUP pin, STOP1 pin, FIREDOWN pin, STOP2 pin;

Described FIREUP pin is connected with pulse generating circuit 1,1 to be connected with change-over switch K1 through popping one's head in,

Described change-over switch K1 is connected with the input end of amplifying circuit 1 by a capacitance, is connected after amplifying circuit 1 with STOP1 pin;

Described FIREDOWN pin is connected with pulse generating circuit 2,2 to be connected with change-over switch K2 through popping one's head in, and described change-over switch K2 is connected with the input end of amplifying circuit 2 by a capacitance, is connected after amplifying circuit 2 with STOP2 pin;

Described MCU module is provided with two IO pins, is connected respectively with the control end of change-over switch K1, K2, for controlling the break-make of change-over switch K1 and probe 1 and 3.3V level, or the break-make of K2 and probe 2 and 3.3V level.

The beneficial effects of the utility model are: after adopting said system, this GP22 chip internal comprises comparer, judges to extract signal by zero passage; Chip completes the algorithm function of FPGA or CPLD automatically, thus eliminates software programming; Adopt double switch can ensure that the vacant state of receiving end is the shortest, the noise be subject to is minimum, so namely saves hardware cost, eliminates again software programming work, shortens the construction cycle, reduce Time To Market.

Accompanying drawing explanation

In order to be illustrated more clearly in the utility model embodiment technical scheme, below the accompanying drawing used required in describing embodiment is briefly described, apparently, accompanying drawing in the following describes is only that the utility model is in order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, below the accompanying drawing used required in p-embodiment or description of the prior art is briefly described, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.

Fig. 1 is the circuit hardware structural drawing of the ultrasonic lung function instrument of current main-stream;

Fig. 2 is that the utility model adopts GP22 to control and the circuit hardware structural drawing of compute chip as core;

Fig. 3 is the control waveform figure of the utility model change-over switch.

Embodiment

Below in conjunction with the accompanying drawing in the utility model embodiment, be clearly and completely described the technical scheme in the utility model embodiment, obviously, described embodiment is only the utility model part embodiment, instead of whole embodiments.Based on the embodiment in the utility model, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the utility model protection.

The circuit hardware structure of the ultrasonic lung function instrument of current main-stream as shown in Figure 1, because gas is very large to the decay of ultrasonic signal, all very little from the amplitude of the signal directly received of popping one's head in, usually less than 5 millivolts, such signal cannot carry out follow-up measurement, therefore needs to amplify.The signal that two-way receives is through amplifying process, zero passage again through comparer after noise reduction judges, just be input in FPGA or CPLD with the form of pulse signal, FPGA or CPLD carries out relevant computing, finally draw the mistiming, this circuit adopts two sends out two patterns received, and 1 probe 2 when launching of namely popping one's head in receives, and pop one's head in 2 transmitting time probe 1 receive.

The control circuit of a kind of ultrasonic lung function instrument as shown in Figure 2, adopts GP22 to substitute FPGA or CPLD, can save comparator circuit or A/D convertor circuit.Because the transmitting terminal of GP22 has high-impedance state, receiving terminal circuit is easily coupled to noise.If signal to noise ratio (S/N ratio) is too small, None-identified to signal, therefore must be managed the noise reducing receiving circuit by GP22.Each Lu Jiayi electronic switch of two-way receiving circuit, carrys out the switching of gauge tap by the software of MCU.Time of reception section by switching over to probe, the non-reception time by switching over to 3.3V.Switch is connected with the input end of amplifier by a capacitance.The output terminal of two-way amplifier is then connected with STOP1, STOP2 pin of GP22 respectively.The control end of K switch 1, K2 is connected respectively to two IO pins of MCU, switches and is controlled by MCU.During owing to being switched to probe, the input end of receiving circuit does not have compulsory DC level, is in vacant state, and is vulnerable to noise.Therefore, be switched to pop one's head in the state linked should be as far as possible short.This just requires, is guaranteeing to receive on the basis of signal leading edge, shortens receiving end and antenna binding time as far as possible, extends and 3.3V level binding time.

The utility model carrys out the switching of gauge tap by MCU, due to the configuration of MCU also control GP22, is therefore convenient to control to switch and the mistiming receiving waveform in sequential.Being switched to and the time point be connected of popping one's head in from being connected with 3.3V, after pulse initial launch time, being controlled by MCU.MCU after sending transponder pulse instruction, can be sent through suitable time delay and connects from 3.3V the instruction being switched to probe, because time delay is at Microsecond grade, can be realized by several non-operation instructions again.Time delay will accomplish the closest forward position receiving waveform of some switching time, can't affect the integrality receiving waveform forward position simultaneously, guarantee not affect measurement result.Such as, in the measurement range of instrument, the transmitting-receiving pulse aerial shortest time is spaced apart 20uS, and switch in this 20uS will be made to be connected with 3.3V as far as possible, and therefore putting switching time should last as far as possible at this 20uS.If MCU machine frequency is 24MHz, single instrction frequency is 2MHz, then single command cycle is 0.5uS, and 20uS is 40 single command cycles.After sending impulse ejection instruction, MCU performs 40 non-operation instructions, just realizes time delay 20uS.In order to ensure the integrality of Received signal strength, we perform 18 non-operation instructions after being set in and sending impulse ejection instruction, then send switching over instruction, are switched to receiving circuit input end and are connected with probe.GP22, once receive signal, just sends interrupt request to MCU, and the interrupt response subroutine of MCU will be connected to be switched to probe again and be connected with 3.3V.FIREUP and the FIREDOWN pin of GP22 is respectively as the control signal input of pulse producer 1 and pulse producer 2.The control waveform of switch as shown in Figure 3.

The foregoing is only preferred embodiment of the present utility model; not in order to limit the utility model; all within spirit of the present utility model and principle, any amendment done, equivalent replacement, improvement etc., all should be included within protection domain of the present utility model.

Claims (1)

1. a control circuit for ultrasonic lung function instrument, is characterized in that: comprise MCU module, control and the GP22 chip of computing for core;

Described MCU module and GP22 chip are configured;

Described GP22 chip is provided with four pins, is respectively FIREUP pin, STOP1 pin, FIREDOWN pin, STOP2 pin;

Described FIREUP pin is connected with pulse generating circuit 1,1 to be connected with change-over switch K1 through popping one's head in,

Described change-over switch K1 is connected with the input end of amplifying circuit 1 by a capacitance, is connected after amplifying circuit 1 with STOP1 pin;

Described FIREDOWN pin is connected with pulse generating circuit 2,2 to be connected with change-over switch K2 through popping one's head in, and described change-over switch K2 is connected with the input end of amplifying circuit 2 by a capacitance, is connected after amplifying circuit 2 with STOP2 pin;

Described MCU module is provided with two IO pins, is connected respectively with the control end of change-over switch K1, K2, for controlling the break-make of change-over switch K1 and probe 1 and 3.3V level, or the break-make of K2 and probe 2 and 3.3V level.