CN217388667U

CN217388667U - Filtering driving circuit for human body electric signals

Info

Publication number: CN217388667U
Application number: CN202220594518.2U
Authority: CN
Inventors: 尹昊
Original assignee: Wuxi Xiatai Biotechnology Co ltd
Current assignee: Wuxi Xiatai Biotechnology Co ltd
Priority date: 2022-03-18
Filing date: 2022-03-18
Publication date: 2022-09-06
Anticipated expiration: 2032-03-18

Abstract

The utility model relates to a human signal of telecommunication control technical field specifically is a filtering drive circuit for human signal of telecommunication, and it can realize falling of the signal of telecommunication and fall, the filtering is anti-interference, exports full signal of telecommunication that satisfies the control demand, and it includes operational amplifier, operational amplifier's normal phase input end connects signal input circuit, signal input circuit includes ESD electrostatic protection diode and high pass filter, operational amplifier's inverting input end links to each other with the output and is the signal of telecommunication output, set up electric capacity decoupling filter circuit between operational amplifier's power end and the earthing terminal.

Description

Filtering driving circuit for human body electric signals

Technical Field

The utility model relates to a human signal of telecommunication control technical field specifically is a filtering drive circuit for human signal of telecommunication.

Background

With the rapid development of wearable electronic medical equipment, the requirement on human body information monitoring is more and more increased in the product design process, so that the requirement on acquisition of bioelectric signals is increased. Human electrical signals have the characteristics of weak strength, low frequency, high impedance, easy interference to machines and the like, and the electrical signals acquired by the existing modules cannot meet the monitoring requirements easily.

Disclosure of Invention

In order to solve the problem that the current human signal of telecommunication is difficult to satisfy the control demand, the utility model provides a filter drive circuit for human signal of telecommunication, it can realize falling of the signal of telecommunication fall make an uproar, the filtering is anti-interference, exports the full signal of telecommunication that satisfies the control demand.

The technical scheme is as follows: the filtering driving circuit for the human body electric signals is characterized by comprising an operational amplifier, wherein a positive phase input end of the operational amplifier is connected with a signal input circuit, the signal input circuit comprises an ESD electrostatic protection diode and a high-pass filter, a negative phase input end of the operational amplifier is connected with an output end and is an electric signal output end, and a capacitance decoupling filtering circuit is arranged between a power supply end and a grounding end of the operational amplifier.

Further characterized in that the high pass filter comprises a resistor R1 and a capacitor C1;

the filter circuit is decoupled to the electric capacity includes decoupling filter power supply circuit and decoupling filter ground circuit, decoupling filter power supply circuit includes the power VCC, power VCC connecting resistance R3 one end, electric capacity C4 one end, electric capacity C5 one end and operational amplifier's power end are connected to the resistance R3 other end, the electric capacity C4 other end with electric capacity C5 other end all grounds, decoupling filter ground circuit includes resistance R2, resistance R2 one end simulation ground, electric capacity C2 one end, electric capacity C3 one end are connected to the resistance R2 other end operational amplifier's earthing terminal, the electric capacity C2 other end with the electric capacity C3 other end all grounds.

Adopt the utility model discloses afterwards, select operational amplifier to constitute reverse voltage follower circuit for use for driving all input signals, ESD electrostatic protection diode realizes the protection, high-pass filter control operational amplifier's high-end turn frequency, sets up electric capacity decoupling filter circuit between operational amplifier's power end and the earthing terminal and adopts electric capacity decoupling filter circuit, has realized falling noise, anti-interference, the filtering to the input signal of telecommunication, obtains the signal of telecommunication of full width of cloth output.

Drawings

FIG. 1 is a schematic block diagram of the hardware of the present invention;

FIG. 2 is a schematic circuit diagram of the present invention;

FIG. 3 is a frequency plot;

fig. 4 is a schematic diagram of an inverse voltage follower circuit.

Detailed Description

Referring to fig. 1 and 2, a filter driving circuit for human body electrical signals includes an operational amplifier, a non-inverting input terminal of the operational amplifier is connected to a signal input circuit, the signal input circuit includes an ESD electrostatic protection diode D1 and a high pass filter, the high pass filter includes a resistor R1 and a capacitor C1, the connection relationship is that the non-inverting input terminal of the operational amplifier is connected to one end of a resistor R1, an anode of the ESD electrostatic protection diode D1 and one end of a capacitor C1, the other end of the capacitor C1 is used as a Vin terminal to input electrical signals, a cathode of the ESD electrostatic protection diode D1 is analog grounded, the other end of the resistor R1 is grounded, an inverting input terminal of the operational amplifier is connected to an output terminal Vout of the electrical signals, and a capacitor decoupling filter circuit is disposed between a power terminal and the ground terminal of the operational amplifier.

The capacitor decoupling filter circuit comprises a decoupling filter power supply circuit and a decoupling filter grounding circuit, the decoupling filter power supply circuit comprises a power supply VCC, the power supply VCC is connected with one end of a resistor R3, the other end of a resistor R3 is connected with one end of a capacitor C4, one end of a capacitor C5 and the power supply end of an operational amplifier, the other end of the capacitor C4 and the other end of a capacitor C5 are both grounded, the decoupling filter grounding circuit comprises a resistor R2, one end of a resistor R2 is grounded in a simulation mode, the other end of the resistor R2 is connected with one end of a capacitor C2, one end of the capacitor C3 and the grounding end of the operational amplifier, and the other end of the capacitor C2 and the other end of the capacitor C3 are both grounded.

ESD electrostatic protection diode D1 principle: an ESD electrostatic protection diode D1 (ESD5Z3.3T1) is connected in parallel in the circuit, when the circuit normally works, the ESD electrostatic protection diode is in a cut-off state (high-resistance state) and does not affect the normal work of a line, when the circuit generates abnormal overvoltage and reaches the breakdown voltage of the circuit, the ESD electrostatic protection diode is rapidly changed from the high-resistance state to the low-resistance state, a low-impedance conduction path is provided for instant current, and meanwhile, the abnormal high voltage is clamped within a safety level, so that the protected IC or the line is protected; when the abnormal overvoltage disappears, the circuit is restored to a high-resistance state, and the circuit works normally.

When the voltage exceeds the conduction voltage of the diode D1 and is more than 3.3V, the conduction is grounded and the normal signal does not reach the conduction voltage and does not reach the voltage, so the normal signal cannot be lost through the ground, and the ESD voltage generally exceeds the conduction voltage, so the diode is conducted, and the ESD voltage is grounded and discharged, so the circuit is not damaged.

High pass filter principle: when the frequency is lower than f ₀ When the signal is inputted into the filter, the output is reduced because the capacitance of the capacitor C1 is very large, and the output is smaller at the lower frequency. When the frequency is higher than f ₀ When the signal is inputted into the filter, the capacitance C1 is very small, so that it has no attenuation effect on the signal, so that the filter has the function of passing high-frequency signal and blocking low-frequency signal, and the turning frequency f of the circuit ₀ Is determined by the following formula:

the graph is shown in fig. 3.

As the spectrum range of the human body bioelectricity signal is mainly concentrated in 0.05-100 Hz, the distribution bandwidth range is limited, and the frequency is relatively low, an active high-pass filter can be formed by connecting a feedback resistor R1(30M omega) and a feedback capacitor C1(0.15 mu) in parallel, so that the high-end turning frequency of the amplifier is 0.05 Hz.

Because human body bioelectric signals are very weak, generally only 0.05 mV-5 mV, and are extremely easy to be interfered, the main tasks are impedance matching and high-pass filtering, and an operational amplifier OPA336 with low voltage, low power consumption and full-amplitude output is selected to form a reverse voltage follower circuit for driving all input signals. The voltage follower is a deep voltage series negative feedback circuit, so that it has high operation precision and large input resistance (input impedance)>10M omega), the output resistance is small, the current which is actually transmitted to the load and is required to be taken from the signal source is extremely small, and V is _IN =V _OUT As shown in fig. 4.

The capacitive decoupling filter circuit has three functions: the energy storage capacitor is used as the energy storage capacitor of the integrated circuit; secondly, high-frequency noise generated by the device is filtered, and a path for transmitting the high-frequency noise through a power supply loop is cut off; and thirdly, the noise carried by the power supply is prevented from interfering the circuit. A decoupling capacitor of 10uF for filtering low-frequency noise; and a decoupling capacitor of 0.1uF is used for filtering high-frequency noise.

Claims

1. The filtering driving circuit for the human body electric signals is characterized by comprising an operational amplifier, wherein the non-inverting input end of the operational amplifier is connected with a signal input circuit, the signal input circuit comprises an ESD electrostatic protection diode and a high-pass filter, the inverting input end of the operational amplifier is connected with the output end and is an electric signal output end, and a capacitance decoupling filtering circuit is arranged between the power supply end and the grounding end of the operational amplifier.

2. The filtering driving circuit for human body electric signals according to claim 1, wherein the high pass filter comprises a resistor R1 and a capacitor C1.

3. The filtering driving circuit for human body electrical signals according to claim 1, wherein the capacitive decoupling filter circuit comprises a decoupling filter power circuit and a decoupling filter ground circuit, the decoupling filter power circuit comprises a power source VCC, the power source VCC is connected to one end of a resistor R3, the other end of the resistor R3 is connected to one end of a capacitor C4, one end of a capacitor C5 and a power supply end of the operational amplifier, the other end of the capacitor C4 and the other end of the capacitor C5 are all grounded, the decoupling filter ground circuit comprises a resistor R2, one end of the resistor R2 is connected to analog ground, the other end of the resistor R2 is connected to one end of a capacitor C2, one end of a capacitor C3 and a ground end of the operational amplifier, and the other end of the capacitor C2 and the other end of the capacitor C3 are all grounded.