Eight channel 24 bit bioelectric acquisition simulation front-end GX1299 software and hardware compatible with ADS1299 for multi-channel sleep monitoring (PSG) application

Multi channel sleep monitoring (PSG) is an objective examination for analyzing sleep structure and evaluating sleep disorders. The PSG monitor collects and records parameters including electroencephalography (EEG), electrooculography (EMG), electromyography (EMG), electrocardiography (ECG), oral and nasal airflow, snoring, respiratory movement, pulse oxygen saturation, and body position. These parameters are displayed in the form of curves, numbers, images, and audiovisual data, forming readable and analytical information data. These signals require high precision, noise suppression capability, and channel synchronization from the acquisition equipment.

The GXSC eight channel 24 bit bioelectric measurement simulation chip GX1299 can replace ADS1299 in situ for multi-channel sleep monitoring. The chip has a built-in programmable gain amplifier (PGA), internal reference, and built-in oscillator, and also integrates common functions required for EEG and ECG applications. The extremely high integration can significantly reduce product size, power consumption, and overall cost. It can be directly powered by batteries and is very suitable for biological signal acquisition in multi-channel sleep monitoring.

The weakness of physiological signals requires the acquisition system to have low noise and high resolution. The GX1299 input reference noise is 1.28 μ Vpp (0.23 μ Vrms), with a 24 bit resolution and an output rate of 250SPS~64kSPS. At an output rate of 250SPS, it can achieve an IRN performance of 1.28 μ Vpp (0.23 μ Vrms); At 64kSPS, it has a -3dB bandwidth of 14.4kHz, with pull-up/pull-down resistors, excitation current traps/sources, and AC lead detection functions.

In addition, GX1299 has a daisy chain configuration, which can solve the problem of cascading data in high channel systems. The digital cache function with a maximum depth of 16 can minimize the frequency of data retrieval, thereby reducing system power consumption. The main features of GX1299 are as follows:

Data rate: 31.25SPS to 32kSPS

• Programmable gain: 1, 2, 3, 4, 6, 8, or 12

Ultra low input reference noise: 4.07 μ Vpp (0.64 μ Vrms) (BW=150Hz, G=6)

• CMRR：120dB

Flexible power consumption modes: High Speed Mode (HS), Low Power Mode (LP), Ultra Low Power Mode (ULP)

Low power mode, with a power consumption of only 410 µ W (AVDD=3V, DVDD=1.8V, ODR=500SPS, G=6)

• Built in low-temperature float benchmark; Built in clock, capable of external output, and adjustable frequency

• Built in driver amplifier, lead dropout detection, temperature sensor, test signal

• Adjustable data cache depth (1/2/4/8/16/32)

Offset/Main error calibration function