[2022] A VCO-based ADC for MEMS Microphones

Silicon Integrated Co., Ltd is a high-tech startup company focus on high-performance mixed-signal IC design. It was founded in January 2016 in Wuhan and it has R&D centers in Europe, Shenzhen and Shanghai. Silicon Integrated has two main product lines: 3D image sensors and smart audio amplifiers. The smart audio amplifier wins over the business by excellent product differentiation, with high quality performance and competitive price. The business value is fully recognized by the tier-one smartphone manufacturers in China.

Project Description

The number of people with hearing impairments or deafness continuously increases every year. The implementation of a digital hearing aid systems and combining this with more programmability for performance on demand and minimum power consumption will improve the hearing experience of patients with hearing loss while reducing the costs and increasing the battery life time. Another application would be monitoring the peoples breathing during night to detect sleep apnea or snoring. The ADC should be able to switch dynamically between modes and must provide the biasing required for the microphone. With the trend of deep-submicron CMOS process, conventional ADC suffers from the low supply voltage and low transistor Gm, which limit the ADC dynamic range and signal-to-noise and distortion ratio. Recently, VCO-based ADCs [1][2] have been reported for audio application, which achieve competitive performance while benefit from technology scaling. The purpose of this project is to further exploit the advantage of VCO-based ADCs for audio application, to reach a small-size PVT-robust solution with competitive performance

Reference:
[1] J. Huang and P. P. Mercier, "A 94.2-dB SNDR 142.6-μW VCO-Based Audio ADC With a Split-ADC Differential Pulse Code Modulation Architecture," in IEEE Solid-State Circuits Letters, vol. 4, pp. 121-124, 2021, doi: 10.1109/LSSC.2021.3092020.
[2] A. Quintero et al., "A Coarse-Fine VCO-ADC for MEMS Microphones With Sampling Synchronization by Data Scrambling," in IEEE Solid-State Circuits Letters, vol. 3, pp. 29-32, 2020, doi: 10.1109/LSSC.2020.2964158

Assignment

• Develop a novel VCO-based ADC for audio application which has:
  ◼ Small area: <0.4mm2
  ◼ Power consumption: < 40uA in low power mode and < 200uA in high performance mode
  ◼ SNDR: about 75dB in low power mode and >90dB in high performance mode with a bandwidth of 20kHz
  ◼ No need for complicated calibration or trimming
• Simulate and tape-out of your ADC
• Measure the performance of your ADC after tape-out.

Requirements

• Familiar with Cadence design tools
• Good knowledge of analog and mixed-signal design
• Good understanding of Data Converters
• Strong communications, documentation, and presentation skills
• Highly self-motivated and enjoying solving difficult challenges

Contact

Last modified: 2023-02-12