An Always-On 0.53-to-13.4 mW Power-Scalable Touchscreen Controller for Ultrathin Touchscreen Displays With Current-Mode Filter and Incremental Hybrid ΔΣ ADC

Abstract

This paper presents an always-on mutual-capacitive touchscreen controller (TSC) with a reconfigurable power consumption of 0.53–13.4 mW, frame rate of 1–120 Hz, and an SNR of 40.0-46.2 dB to support not only a normal sensing mode but also a low-power (LP) and an ultra-low-power (ULP) modes. For the LP and ULP modes, the power-frame rate scalability is realized by a frame rate controller, which turns off analog front-end (AFE) transmitter (TX) and receiver (RX) periodically. Moreover, the TSC improves an out-of-band noise attenuation by utilizing a sixth-order current-mode band-pass filter and second-order incremental hybrid delta-sigma (ΔΣ) modulator, providing an SNR up to 45.8 dB when the display on. The prototype TSC is fabricated in an 80-nm high-voltage CMOS technology with an active area of 4.873 mm2.