WO2016045456A1

WO2016045456A1 - Ultra-low power consumption electrodeless capacitor volume measurement circuit and method applicable in heart rate monitoring

Info

Publication number: WO2016045456A1
Application number: PCT/CN2015/086183
Authority: WO
Inventors: 崔予红
Original assignee: 成都维客亲源健康科技有限公司
Priority date: 2014-09-28
Filing date: 2015-08-05
Publication date: 2016-03-31
Also published as: CN104257377B; CN104257377A

Abstract

Ultra-low power consumption electrodeless resistor volume measurement circuit and method applicable in heart rate measurement monitoring. The circuit comprises pulse signal source P, integrating capacitor C1, sampling capacitor C2, operational amplifier OPA1, a bandpass filter, analog switch SW1, analog switch SW2, analog switch SW3, an analog-to-digital converter, an MCU, and two skin contact ends. Analog switch SW2 is connected to integrating capacitor C1. An output of integrating capacitor C1 is connected to sampling capacitor C2 via analog switch SW3. An output of sampling capacitor C2 is connected to an input of operational amplifier OPA1. An output of operational amplifier OPA1 is connected to the bandpass filter. An output of the bandpass filter is connected to the MCU. The need for inert noble metal electrodes is obviated, the need to apply in advance an electrically-conductive paste is obviated, measurement is not affected by sweating of the human body, at the same time, advantages of low costs and ultralow power consumption are provided. This is applicable in a high-performance intelligent wearable device.

Description

Ultra-thin power consumption electrodeless resistance volume measuring circuit and method suitable for heart rate detection

Technical field

[0001] The present invention relates to an ultra low power electrodeless resistance volume measuring circuit and method suitable for heart rate detection.

Background technique

[0002] With the advancement of society and the improvement of living standards, people's health needs are also getting higher and higher. The traditional health management model for sick and sick patients can no longer meet people's further needs for health. People hope to be able to Get a new environment, comfortable body, green, harmless, comprehensive and accurate, economical and convenient, and can prevent new problems.

[0003] In health-detection-based wearable devices, heart rate detection is a very common requirement. Resistive volumetric acquisition of capillary network congestion is a common method of signal acquisition for heart rate detection. In traditional measurement methods, an inert metal electrode is often required to contact the skin for measurement, which is not suitable for wearable devices. The invention does not need an inert precious metal electrode, and does not need to apply a conductive paste in advance, and the sweating of the human body has no influence on the measurement, and has the advantages of low cost and extremely low power consumption, and is suitable for a wearable device.

technical problem

[0004] The object of the present invention is to overcome the deficiencies of the prior art, and to provide a heart rhythm detection that does not require an inert precious metal electrode, does not require prior application of a conductive paste, has no effect on the measurement of sweating of the human body, is low in cost, and is suitable for a wearable device. Ultra-low power electrodeless resistance volume measurement circuit and method.

Problem solution

Technical solution

[0005] The object of the present invention is achieved by the following technical solutions: an ultra-low power electrodeless resistance volume measuring circuit suitable for heart rate detection, which includes a pulse signal source P, an integrating capacitor C1, a sampling capacitor C2, an operational amplifier ΟΡΑ1 , bandpass filter, analog switch SW1, analog switch SW2, analog switch SW3, analog to digital converter, MCU and two skin contact terminals, one of the skin contact ends is connected to the pulse signal source P, and the other skin contact The terminals are respectively connected to one ends of the analog switches SW1 and SW2, and the other one of the SW2 switches is simulated. The terminal is connected to the integrating capacitor CI, the output of the integrating capacitor CI is connected to one end of the analog switch SW3, the other end of the analog switch SW3 is connected to the sampling capacitor C2, and the output of the sampling capacitor C2 is connected with the non-inverting input terminal of the operational amplifier OPA1, The output of the amplifier OPA1 is respectively connected to the inverting input of the operational amplifier OPA1 and the input of the band pass filter, the output of the band pass filter is connected to the analog to digital converter, and the output of the analog to digital converter is connected to the MCU. The other end of the analog switch SW1, the other end of the integrating capacitor C1, and the other end of the sampling capacitor C2 are connected to the ground.

[0006] An ultra-low power electrodeless resistance volume measuring circuit suitable for heart rate detection further includes a logic circuit connected to a control signal input terminal of the analog switches SW1, SW2, and SW3 for controlling the analog port. Turn off the closing of SW1, SW2, and SW3.

[0007] The band pass filter is mainly composed of an operational amplifier OPA2, a resistor R1, a resistor R2, a capacitor C3 and a capacitor C4. The output of the operational amplifier OPA1 is coupled to the inverting input terminal of the operational amplifier OPA2 via a resistor R1 and a capacitor C3. The resistor R2 and the capacitor C4 are connected in parallel to form a negative feedback loop.

[0008] The skin equivalent circuit S is composed of a capacitor and a resistor in series.

[0009] The operational amplifier OPA1 and the operational amplifier OPA2 are low power operational amplifiers.

[0010] The analog switches SW1, SW2 and SW3 are high-speed analog switches.

[0011] The ultra low power consumption electrodeless resistance volume measuring circuit suitable for heart rate detection according to claim 1 is used for a heart rate detection method, which comprises the following substeps:

[0012] S1: Before the detection, the high-speed analog switch SW1 and the high-speed analog switch SW2 discharge the integrated capacitor C1 under the control of the sequence;

[0013] S2: At the beginning of the detection, the two skin contact ends contact the skin, and the pulse signal source outputs a step signal sequence, and the high-speed analog switch SW1 and the high-speed analog switch SW2 are controlled under the control of the logic circuit, and the integral is performed. Capacitor C1 accumulates charge;

[0014] S3: under the control of the high-speed analog switch SW3, the charge accumulated by the integral capacitor C1 is transferred to the sampling capacitor C2;

[0015] S4: The voltage of the sampling capacitor C2 is buffered by the operational amplifier OPA1, and then sent to the bandpass filter network of the operational amplifier OPA2;

[0016] S5: It is quantized by an analog-to-digital converter and input to the microprocessor MCU for processing.

[0017] The sequence of the high-speed analog switch SW2 is the same as the sequence of the step signal output by the pulse signal source P, high The speed simulation SW1 and SW2 have the same closed sequence frequency, opposite phase, equal amplitude and no overlap, and the high-speed analog switch SW3 is always closed.

Advantageous effects of the invention

Beneficial effect

[0018] The beneficial effects of the present invention are: The invention detects the equivalent circuit formed on the skin contact end, and the pulse signal source outputs a step signal sequence, and under the control of the logic circuit, the SW1 and the SW2 are clamped, and the C1 integral is performed. The charge is accumulated on the capacitor; under the control of SW3, the charge of C1 is transferred to the C2 sampling capacitor; the voltage of the sampling capacitor is buffered by OPA1 and sent to the bandpass filter network of OPA2, and then quantized by the digital-to-analog converter. Algorithm processing. The invention does not need an inert precious metal electrode, and does not need to be coated with a conductive paste in advance, and the sweating of the human body has no influence on the measurement, and has the advantages of low cost and low power consumption, and is suitable for high-performance smart wearable devices.

Brief description of the drawing

DRAWINGS

1 is a circuit structure diagram of the present invention;

2 is a flow chart of a method of the present invention;

[0021] FIG. 3 is a typical waveform diagram of a pulse signal source and a gate according to the present invention.

Embodiments of the invention

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings: As shown in FIG. 1, an ultra-low power electrodeless resistance volume measuring circuit suitable for heart rate detection, which includes a pulse signal source P, an integrating capacitor Cl, and a sampling Capacitor C2, Operational Amplifier ΟΡΑ1, Bandpass Filter, Analog Shutdown SW1, Analog Shutdown SW2, Analog Shutdown SW3, Analog to Digital Converter, MCU and Two Skin Contact Ends, One Skin Contact and Pulse Signal Source P Connected, the other skin contact end is connected to one end of the analog switch SW1 and SW2 respectively, and the other end of the analog switch SW2 is connected with the integral capacitor C1, and the output of the integral capacitor C1 is connected with one end of the analog switch SW3, and the analog SW3 is connected. The other end is connected to the sampling capacitor C2. The output of the sampling capacitor C2 is connected to the non-inverting input of the operational amplifier OPA1. The output of the operational amplifier OPA1 is respectively connected to the inverting input of the operational amplifier OPA 1 and the input of the band pass filter. , the output of the bandpass filter and the modulus The converter is connected, the output of the analog-to-digital converter is connected to the MCU, the other end of the analog switch SW1, the other end of the integrating capacitor C1 and the other end of the sampling capacitor C2 are connected to the ground.

[0023] The ultra-low power electrodeless resistance volume measuring circuit suitable for heart rate detection further comprises a logic circuit, and the logic circuit is connected with the control signal input ends of the analog switches SW1, SW2 and SW3 for controlling the simulation. Turn off the closing of SW1, SW2, and SW3.

[0024] The band pass filter is mainly composed of an operational amplifier OPA2, a resistor R1, a resistor R2, a capacitor C3 and a capacitor C4. The output of the operational amplifier OPA1 is coupled to the inverting input terminal of the operational amplifier OPA2 via a resistor R1 and a capacitor C3. The resistor R2 and the capacitor C4 are connected in parallel to form a negative feedback loop.

[0025] The skin equivalent circuit S is composed of a capacitor and a resistor in series.

The operational amplifier OPA1 and the operational amplifier OPA2 are low power operational amplifiers.

[0027] The analog switches SW1, SW2 and SW3 are high speed analog switches.

[0028] As shown in FIG. 2, the ultra low power consumption electrodeless resistance volume measuring circuit suitable for heart rate detection according to claim 1 is used for heart rate detection and measurement, characterized in that it comprises the following substeps:

[0029] S1: Before the detection, the high-speed analog switch SW1 and the high-speed analog switch SW2 discharge the integrated capacitor C1 under the control of the sequence;

[0030] S2: When the detection starts, the two skin contact ends contact the skin, and the pulse signal source outputs a step signal sequence, and the high-speed analog switch SW1 and the high-speed analog switch SW2 are controlled under the control of the logic circuit, and the integral is performed. Capacitor C1 accumulates charge;

[0031] S3: under the control of the high-speed analog switch SW3, the charge accumulated by the integrating capacitor C1 is transferred to the sampling capacitor C2;

[0032] S4: The voltage of the sampling capacitor C2 is buffered by the operational amplifier OPA1, and then sent to the bandpass filter network of the operational amplifier OPA2;

[0033] S5: It is quantized by an analog-to-digital converter and input to the microprocessor MCU for processing.

[0034] The step signal sequence of the pulse signal source output, the high-speed analog switch SW1, the high-speed analog switch SW2, and the high-speed analog switch SW3 are shown in FIG. 3, and the high-speed analog switch SW2 is closed. The sequence is the same as the sequence of the step signal output from the pulse signal source P. The high-speed analog switches SW1 and SW2 have the same closed sequence frequency, opposite phase, equal amplitude and no overlap, and the high-speed analog switch SW3 is always closed.

Claims

Claim

[Claim 1] An ultra-low power electrodeless resistance volume measuring circuit suitable for heart rate detection, comprising: a pulse signal source P, an integrating capacitor C1, a sampling capacitor C2, an operational amplifier OPA1, a band pass filter, and an analog Shaoguan SW1, analog switch SW2, analog switch SW3, analog-to-digital converter, MCU and two skin contact terminals, one skin contact end is connected with pulse signal source P, and the other skin contact end is connected with analog switch SW1 Connected to one end of SW2, the other end of analog switch SW2 is connected with integral capacitor C1, the output of integral capacitor C1 is connected with one end of analog switch SW3, the other end of analog switch SW3 is connected with sampling capacitor C2, sampling capacitor C2 The output is connected to the non-inverting input of the operational amplifier OPA1, and the output of the operational amplifier OPA1 is respectively connected to the inverting input of the operational amplifier OPA1 and the input of the band-pass filter, and the output of the bandpass filter is connected to the analog-to-digital converter. The output of the analog-to-digital converter is connected to the MCU, and the other end of the analog SW1 is connected to the other end of the integrating capacitor C1. The other terminal of the sampling capacitor C2 is connected to ground.

[Claim 2] The ultra low power consumption electrodeless resistance volume measuring circuit suitable for heart rate detection according to claim 1, characterized in that: it further comprises a logic circuit, said logic circuit and analog switch SW1 The control signal input terminals of SW2 and SW3 are connected to control the closing of the analog switches SW1, SW2 and SW3.

[Claim 3] The ultra-low power electrodeless resistance volume measuring circuit suitable for heart rate detection according to claim 1, wherein: the band pass filter is mainly composed of an operational amplifier OPA2, a resistor R1, and a resistor R2. Capacitor C3 and capacitor C4, the output of the operational amplifier OPA1 is coupled to the inverting input terminal of the operational amplifier OPA2 via the resistor R1 and the capacitor C3, and the resistor R2 and the capacitor C4 are connected in parallel to form a negative feedback loop.

[Claim 4] The ultra-low power electrodeless resistance volume measuring circuit suitable for heart rate detection according to claim 1, wherein: said skin equivalent circuit S is composed of a capacitor and a resistor in series.

[Claim 5] The ultra low power consumption electrodeless resistance volume measuring circuit suitable for heart rate detection according to claim 1 or 3, wherein: the operational amplifier OPA1 and the operational amplifier OPA2 are low power operational amplifiers .

[Claim 6] The ultra low power consumption electrodeless resistance volume measuring circuit suitable for heart rate detection according to claim 1, wherein: said analog switches SW1, SW2 and SW3 are high speed analog switches.

[Claim 7] An ultra-low power electrodeless resistance volume measuring method suitable for heart rate detection, characterized in that it comprises the following substeps:

S1: Before the detection, the high-speed analog switch SW1 and the high-speed analog switch SW2 discharge the integral capacitor C1 under the control of the sequence;

S2: At the beginning of the detection, the two skin contact ends contact the skin, and the pulse signal source outputs a step signal sequence, and the high-speed analog switch SW1 and the high-speed analog switch SW2 are controlled under the control of the logic circuit, and the integral capacitor C1 is accumulated. Electric charge

S3: under the control of the high-speed analog switch SW3, transfer the accumulated charge of the integral capacitor C1 to the sampling capacitor C2;

S4: The voltage of the sampling capacitor C2 is buffered by the operational amplifier OPA1, and then sent to the bandpass filter network of the operational amplifier OPA2;

S5: It is quantized by an analog-to-digital converter and input to the microprocessor MCU for processing.