Input Impedance Chopper Stabilized Amplifier with Dual Feedback Loops Input Impedance Technique 3 Architecture CCIA(Capacitively-coupled Chopper Instrumental Amplifier) core with RRL(Ripple Reduction Loop) & SS-DSL(Single-slope-assisted DC-servo Loop) PGA and 10b SAR ADC DPFL(Dual Positive Feedback Loops) for impedance boosting Signal generator and automatic calibration logic for external parasitics adaptation Characteristics Verified IP CCIA(Capacitively-coupled Chopper Instrumental… Continue reading Technique III: Input Impedance Chopper Stabilized Amplifier with Dual Positive Feedback Loops

Parasitic Insensitive Impedance Boosting with 4-tap FIR Impedance Boosting Technique 2 Architecture CTDSM using low noise linear integrator & VCO-based quantizer Parasitic insensitive impedance boosting with 4-tap FIR Current recycling OPAMP and chopper stabilization for integrator noise reduction VCO based quantizer and 2nd order noise shaping for quantization noise reduction Block Diagram Performance – SNDR,… Continue reading Technique II: Parasitic Intensive Impedance Boosting with 4-tap FIR

Impedance Boosting with Additional Amplifier Impedance Boosting Technique I Architecture Truncation error shaping using the NS-SAR ADC 1st-order DT DSM with CDS integrator and 2nd-order NS SAR quantizer Performance – SNDR, IRN SNDR(Signal to Noise/Distortion Ratio) : 94.5dB at 500Hz BW IRN(Input Referred Noise) : 0.174 µV/√Hz Back to Technology

ExG Biosignal Acquisition Low Power, Low Noise, High CMRR, High Input Impedance and Wide Input Range Challenges Low power consumption : <10 μW Low noise : <1 μVrms Large input swing : >200 mVPP Wide dynamic range : >90 dB High CMRR : >70 dB High input impedance : >100 MΩ Obstacles in ExG Biosignal… Continue reading ExG Biosignal Acquisition

Neurotherapeutics Wide Dynamic Range and Low Input-referred Noise IC Challenges Stimulation Artifact Motion Artifact Circuit Noise Solution – Adaptive Amplifier Gain & ADC Resolution Control Low Amplitude Signal -> High Gain & Low DR High Amplitude Signal -> Low Gain & High DR Increased Dynamic Range with Auto-ranging & AGC Power efficient digital conversion with… Continue reading Neurotherapeutics

CM Charge Pumping Stable and Simple Circuit Structure and Operation CM signal sensed at the input of the front-end LNA If the CM signal exceeds the desired CM range, the displacement current from the CM input absorbed by a CMCP Input swing kept within the desired CM range, even in the presence of excessively large… Continue reading CM Charge Pumping

CMCP with Adaptive CM Cancelling Stable and Simple Circuit Structure and Operation CM signal suppression loop operation Adaptive CM cancelling loop added for TCMRR improvement Using LMS algorithm and differential displacement current control, CM-to-DM conversion minimized even in the presence of circuit and electrode mismatches Block Diagram Pros No stability issue caused by the variation… Continue reading CMCP with Adaptive CM Cancelling

Pseudo Right-leg-drive (RLD) Stable and Simple Circuit Structure and Operation VCM extracted at the output of the front-end LNA According to VCM, CM current sources at the input controlled by the adaptive bias circuit CM current provided to absorb CM fluctuations at the LNA input Block Diagram Pros No stability issue caused by the variation… Continue reading Pseudo Right-leg-drive (RLD)