High-precision GX1641 ADC-based oximeter application program, compatible with AD7793

With the increase of people‘s awareness of health, the application of oximeters is becoming more and more important in the field of healthcare and medical research. Oximeters are mainly used to monitor blood oxygen saturation, which can detect lung and cardiovascular diseases and other health problems in time. This paper focuses on the application characteristics of a high-precision ADC chip, GX1641, in oximeters.GX1641 is a Sigma-Delta type ADC chip, and the advantages of the technology are large dynamic range, strong anti-dislocation, high noise immunity and good reliability. accuracy and stability of oximeter.

The application principle of GX1641 in oximeter: oximeter mainly consists of an LED light source and a photodiode. the LED is used to emit infrared and red light, which penetrates the blood and is received by the photodiode. the light signals enter the photodiode and are then transmitted to the blood. After entering the photodiode, the light signal is converted into an electrical signal and amplified by an amplifier. It is then input to the GX1641 for digitization.

GX1641 main performance and application introduction: GX1641 is a low-power, low-noise 24-bit ADC, which contains three differential analog inputs, but also integrated on-chip low-noise instrumentation amplifier, and thus can be directly input to the small signal. GX1641 can be used with an internal clock or an external clock operation, the output data rate can be programmed through the software to set up the output data rate, which can be varied in the range of 4.17Hz to 940Hz. The GX1641 can be clocked internally or externally and the output data rate can be programmed by software to vary from 4.17Hz to 940Hz.

The performance parameters are as follows:

Operating voltage range: 2.7V-5.25V

Root-mean-square (RMS) noise: 38nV (at 4.17Hz); 79nV (at 16.7Hz)

Power consumption: 360uA in operating mode

Supports 15 update rates: 4.17Hz~940Hz

3-channel differential signal input

Built-in low noise amplifier

Gain steps 0.5/1/2/4/8/16/32/64/128 times selectable

Built-in RCO circuit, default frequency 64K

Built-in programmable current source, bias voltage generator

SPI communication interface: support standard 3-wire SPI interface, support up to 5M SCLK communication clock, support CRC and XOR checksum.

In summary, the oximeter based on high-precision GX1641 ADC technology is characterized by high accuracy, high resolution and high sensitivity, high reliability, and good user experience. It can effectively improve the quality and efficiency of medical treatment and health management, and provide more accurate and convenient health management services for the majority of users. GX1641 can provide technical support and supply channels throughout the whole process if required.