JPS5849135A - Power source circuit of automatic 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 The present invention relates to an automatic electronic blood pressure monitor that detects Korotkoff sounds and measures blood pressure using a click and a piezoelectric microphone attached to the upper arm, and particularly relates to the configuration of its power supply circuit. .

Conventional electronic sphygmomanometers use batteries as a power source, and use rubber bulbs for air supply and exhaustion.The power consumption is constant and low, and the pressure conversion, Korotkoff sound detection, and judgment circuits are connected from the power source through a voltage stabilization circuit. It was driving. In addition, automatic blood pressure monitors that use pressure pumps and solenoid valves for pumping and exhausting have a power supply unit that drives the voltage stabilizing circuit from the commercial power source via a power transformer and current circuit, and are battery-operated. Because they require higher reliability than manual pump/exhaust sphygmomanometers, they require a high-grade power supply circuit and are therefore expensive products, so they are often used for commercial purposes.

The present invention uses a pressurized bong for air supply and exhaust while being battery-powered.
It is possible to provide an effective power supply circuit suitable for automatic blood pressure monitors that automatically operate with solenoid valves, and to
The present invention provides a blood pressure monitor having a voltage stabilizing circuit at stage t2, in which voltage fluctuations do not affect pressure accuracy.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plot diagram showing the entire blood pressure monitor of the present invention.
2 is the blood pressure monitor body, and 2 is the cuff (arm cuff). A rubber bag 3 is housed inside the cuff 2 and has a reel so that it can be wrapped around the upper arm of the person to be measured to perform blood pressure measurement. 4 is a piezoelectric microphone, which is connected to the blood pressure monitor body 1 via the jack 5.
Incorporate Korotkoff sounds and pulse sounds. 6 is a detection circuit that extracts only the Korotkoff sound from the signal of the piezoelectric microphone 4, and is a 40 Hz peak active filter composed of an operational amplifier driven at 10 V. 7 is a pulse sound detection band-pass filter for similarly extracting pulse sound.

8 is the big man who controls the operation, controls the entire device by obtaining input from the pressure sensor, Korotkoff sound and pulse sound;
This is a microcomputer that measures blood pressure.

Reference numeral 9 is a start key for keying in the start of measurement, IO is a reset key for initializing the microcomputer 8, and 11 is a pulse key for displaying the pulse rate on the display section. Reference numeral 12 denotes a buzzer which notifies the user of the status of the device, such as the presence of Korotkoff sounds and errors.

Reference numeral 13 indicates a status indicator light made of a light emitting diode, which is a plurality of independent indicator lights indicating during measurement, battery replacement, and errors. 14 is a fluorescent display tube that displays the measured blood pressure value or pulse rate. The input keys and display centering on the microcomputer are all operated at IOV, and the microcomputer is required to have a voltage fluctuation of ±10% or less in order to work without malfunction. 1
Reference numeral 5 is a constant speed pressure reducing valve, which is fluidly connected to the rubber bag 3 of the cuff 2 by a rubber tube 16 inside the main body and an air plug 17, and is relatively independent of the cuff pressure and has a constant speed of 3 to 4 waHg.
Try to maintain a decompression speed of about 1/2 beat. 18 is a solenoid valve, and 19 is its driver. The electromagnetic valve 18 is connected to the rubber tube 16 and is a quick release valve that is directly driven by a battery voltage of 9V, and is controlled by the microcomputer 8 so that the air in the cuff 2 is rapidly released when the measurement is completed. Ru.

20Fi pressure pump, 21 is its driver. .

The pressurizing pump 20 sends pressurized air to the rubber bag 3 of the cuff 2 through the rubber tube 16 using an eccentric pin attached to the output shaft of the commutator motor and a diaphragm. The electromagnetic valve 18 and the pressurizing pump 20 are required to have a large power so that they can perform a certain depressurization and pressurization within a predetermined time.
The current consumption is ~700mA. Therefore, when this is driven by a battery, approximately 1
A drop in electromotive force due to the battery's internal resistance close to V was observed.

Although the performance of the first load section deteriorates due to a decrease in the negative source voltage due to battery consumption, etc., the function is designed to work even if the battery voltage decreases to 7V.

22 is a semiconductor pressure sensor, and the input voltage eEi pressure is
P1 This is a transducer that converts pressure into voltage so that the following equation holds when the output voltage is go.

Eo = Esc (KtΔP 10Kg) However,...! = Constant As is clear from the above equation, the output of the pressure sensor 22 is completely linear with the input voltage, and in order to improve the pressure accuracy, the manual power of the pressure sensor 22 as the third load has almost no voltage fluctuation. It shouldn't be.

23 is an A/D converter that converts the analog output of the pressure sensor 22 into digital data for input into the microcomputer 8. 24 is the power supply, which consists of six AA batteries and a stabilizing circuit.

25 is the first stabilized power supply, which is a DC-D that stably provides an output of 10V±10% when the battery output is directly input.
It is a C converter. The first stabilized power supply 25 causes almost no fluctuation in the output voltage if the input voltage is in the range of 11V to 7VDC. 26 is a second stabilized power supply that supplies a stabilizer voltage tS of 5V from the output of the first stabilized power supply 25 of IOV stabilized to ±10%, and has only the pressure sensor 22 as a third load as a load. There is.

Next, the operation of this embodiment will be explained. ``In order to measure blood pressure, when the user wraps the cuff 2 around his upper arm and presses the start key 9, the pressurizing pump 20 is driven by the program of the microcomputer 8, and the cuff 2 is pressurized. Since the pressurizing pump 20 as the first load consumes a large current, the terminal voltage of the battery drops, but the voltage drop is about IV. Since it is within the permissible range of the first stabilized power supply 25 that generates the voltage,
The output voltage is within the predetermined IOV±10%, and there is no malfunction of the microcomputer 8 or the like due to insufficient voltage. When the battery is exhausted and the voltage is 7V or less, before the operation of the first stabilized power supply 25 becomes unstable, a voltage checker (not shown) in the control circuit as the second load operates and displays the battery replacement status. At the same time, the sequence of the microcomputer 8 is locked, so that measurement errors do not occur. When 160sa+Hg is detected by the pressure sensor 22, the drive of the pressurizing pump 20 is stopped, and while reducing the pressure,
The presence or absence of Korotkoff sound is detected by the filter circuit sections 6 and 7, but when the piezoelectric microphone 40 input is large, the current flowing through the filter circuit is shockingly large, so the IOV line as the second load/the entire Although there is a small ripple, since the second stabilized power supply 26 is provided to the pressure sensor 22, voltage fluctuations are not transmitted to the pressure sensor 22, so pressure accuracy is not impaired.

In the blood pressure monitor of the present invention, when the systolic blood pressure and diastolic blood pressure are recognized by the sequence of the microcomputer 8, which takes into account external noise and arrhythmia, these values are displayed on a fluorescent table.
The pressure pump and solenoid valve are driven by batteries, which consume a large amount of current.

In order to efficiently convert the voltage to the control unit as a second load, which has a total current consumption of about 50 mA, but requires some degree of stabilization (±10%), it has a first stabilized power supply. Therefore, voltage fluctuations due to ON-OFF of the first load will not cause the control circuit as the second load to malfunction. Furthermore, even if the input to the first stabilized power supply drops due to battery depletion, sufficient voltage can be supplied to the second load until the voltage check circuit drops below a predetermined voltage, which can cause the microcomputer to run out of control. No measurement errors will occur. Furthermore, even if the signal input from the piezoelectric microphone 4 is large and the voltage across the entire second load may have some ripples, the second stabilized power supply suppresses the output voltage fluctuation by ±0.
Since the accuracy is kept to 2% or less, the accuracy of the pressure value is hardly affected.

Also, when using the AC adapter output as the first load power source instead of a battery, the AC adapter includes
Even if there is a ripple, there is no functional problem for the pressurizing pump 20 and the solenoid valve 1B, and since the ripple is removed by the first stabilized power supply, the control circuit can operate stably. . Since the power supply device according to the present invention has the minimum necessary stabilized power source, it can be made cheaper than when the voltage of the entire device is stabilized.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the entire electronic blood pressure monitor of the present invention;
FIG. 2 is a simplified circuit diagram of the power supply device.

Claims (1)

[Claims] 1. Voltage fluctuations do not affect functionality due to high current consumption, such as pressurizing pumps that forcefully feed pressurized air to the cuff band or solenoid valves that rapidly exhaust pressurized air from the cuff band. The first load section (a microcomputer that is directly driven by the power output from a battery or an AC adapter and controls the entire sequence,
A second load section that is required to be relatively stabilized, such as a logic circuit section, is supplied via the first voltage stabilization circuit, and is directly related to pressure accuracy and is most stabilized. 1. To the third load section that requires 1. A power supply circuit for an automatic blood pressure monitor, characterized in that the output of a second voltage stabilizing circuit is supplied by stabilizing the output of the first voltage stabilizing circuit to a predetermined voltage.