JPS61191339A - Electronic hemomanometer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an electronic blood pressure monitor.

An electronic blood pressure monitor based on the conventional auscultation method has a configuration as shown in FIG. First, the measurement principle will be explained.

A cuff 1 is wrapped around the arm and pressure is applied with a rubber ball 2 to stop the bleeding.

The air in the cuff 1 is gradually exhausted while observing the pressure with a pressure detection circuit 3 and the Korotkoff sound with a microphone 4 fixed to the cuff 1 and a Korotkoff sound detection circuit 5.

The pressure at the time when the Korotkoff sounds start to be detected is the systolic blood pressure, and the pressure at which the Korotkoff sounds are last detected is the diastolic blood pressure. This determination is made by the signal processing section 6 and displayed on the display section 7. 8 is a rubber tube.

In the past, the pressure detection circuit 3 was constructed as shown in FIG. That is, the output signal of the semiconductor pressure sensor 9 is amplified by the amplifier 10, and the A/D converter 11
Pressure was detected by D conversion. 12 is a constant current circuit.

Problems to be Solved by the Invention In an electronic blood pressure monitor that applies pressure using a rubber bulb 2, the pressure value rises steeply when the rubber bulb 2 is compressed, causing overshoot. Therefore, the analog value of pressure, ie, the output signal of the amplifier 10 shown in FIG. 5, changes as shown in FIG. 6 when pressurizing. Then, when transitioning to the low-speed exhaust measurement state after completion of pressurization, the pressure drops sharply by several +5 mHo. For this reason, measurement sometimes started at a pressure that was several + m5Ho lower than the target pressurization value. Further, during pressurization, the pressure value changes greatly due to the above-mentioned overshoot of the pressure value, and there is a problem that it is difficult to read the pressure during pressurization.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an electronic sphygmomanometer equipped with a pressure detection circuit that can cancel out the adverse effects of sudden changes in pressure during pressurization.

Means for Solving the Problems In order to solve the above problems, the electronic blood pressure monitor includes a semiconductor pressure sensor that detects the pressure of a hemostatic cuff pressurized by a rubber bulb, and a constant current applied to this semiconductor pressure sensor. A constant current circuit that supplies the semiconductor pressure sensor, an analog-to-digital converter that converts the output signal of the semiconductor pressure sensor into a digital signal and supplies the signal to a signal processing section, and is connected between the semiconductor pressure sensor and the analog-to-digital converter. This configuration includes a pressure detection circuit having a series circuit of a low-pass filter and an amplifier.

Effect According to the above configuration, due to the effect of the low-pass filter,
Since the pressure overshoot during pressurization no longer appears in the analog value of the pressure signal, the steep fall of the analog value of the pressure signal when transitioning to low-speed exhaust immediately after pressurization is completed is eliminated, and at the same time, the pressure overshoot during pressurization disappears. The range of change in the pressure display also becomes smaller.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

FIG. 1 is a circuit block diagram of a pressure detection circuit for an electronic light pressure needle according to a first embodiment of the present invention. Reference numeral 21 is a constant current circuit that supplies a constant current to a semiconductor pressure sensor 22. FIG. 23 is a low-pass filter, which uses the output signal of the semiconductor pressure sensor 22 as an input signal. 24 is an amplifier, which amplifies the output signal of the low-pass filter 23. 25 is an A/D converter, which converts the output signal of the amplifier 24 into A/D. 2
6 is a signal processing section.

Hereinafter, the effects of the above configuration will be explained.

The passband of the low-pass filter 23 is sufficient to smooth the overshoot of the pressure signal during pressurization by the rubber bulb 2 as shown in FIG. It is set to follow. the result,
As shown in Figure 2, the analog value of the pressure signal, that is, the A/D
Overshoot when pressurizing the input signal to the converter 25 is reduced.

In addition, large changes in the pressure display value during pressurization and steep falls in the pressure display value when transitioning to low-speed exhaust after completion of pressurization are eliminated.

FIG. 2 is a circuit block diagram of a pressure detection circuit of an electronic blood pressure monitor according to a second embodiment of the present invention. The difference from the first embodiment is that the connection positions of the low-pass filter 23 and the amplifier 24 are swapped. It is a point. Even with such a configuration, effects similar to those of the first embodiment can be obtained.

Effects of the Invention As described above, according to the present invention, large fluctuations in the pressure display value during pressurization and a steep fall in the pressure display value when transitioning to low-speed exhaust after completion of pressurization can be suppressed. ,
As a result, pressurization up to the pressurization target value can be reliably performed.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram of a pressure detection circuit of an electronic blood pressure monitor according to the first embodiment of the present invention, FIG. The figure is a circuit block diagram of a pressure detection circuit of an electronic blood pressure monitor according to the second embodiment of the present invention, and FIG. 4 is a configuration diagram of the electronic blood pressure monitor.
FIG. 5 is a circuit block diagram of a pressure detection circuit of a conventional electronic blood pressure monitor, and FIG. 6 is an explanatory diagram of changes in analog values of pressure signals during pressurization of the pressure detection circuit. DESCRIPTION OF SYMBOLS 1... Bracelet, 2... Rubber bulb, 21... Constant current circuit, 22... Semiconductor pressure sensor, 23... Low pass filter, 24... Amplifier, 25... A/D converter,
2G...Signal Processing Department Agent Yoshi Morimoto
Hiro Figure 2 Current status Figure S Figure 4 ◇ Figure 5

Claims (1)

[Scope of Claims] 1. A semiconductor pressure sensor that detects the pressure of a hemostatic cuff pressurized by a rubber bulb, a constant current circuit that supplies a constant current to this semiconductor pressure sensor, and an output of the semiconductor pressure sensor. A pressure sensor comprising: an analog-to-digital converter that exchanges a signal into a digital signal and supplies the signal to a signal processing section; and a series circuit of a low-pass filter and an amplifier connected between the semiconductor pressure sensor and the analog-to-digital converter. Electronic blood pressure monitor with detection circuit. 2. The electronic blood pressure monitor according to claim 1, wherein the low-pass filter is connected upstream of the amplifier. 3. The electronic blood pressure monitor according to claim 1, wherein the low-pass filter is connected after the amplifier.