3.3V mixed-mode IC design using switched-current techniques for speech applications

T. H. Kuo, S. Y. Lee

Research output: Contribution to journalArticlepeer-review


A low-cost, low-voltage, mixed-mode integrated circuit for speech applications is presented. The mixed-mode 1C can directly preamplify speech signals with the aid of automatic gain control, convert amplified signals to 1-bit digital codes at 24kbit/s, store the converted codes in memory, and replay the stored codes through an on-chip current-input voltageoutput power amplifier. Switched-current techniques are used to implement a filter with a 3.4kHz bandwidth and a 96kHz sampling frequency, and also an adaptive delta modulator (ADM) with a 24kHz sampling frequency. Measured dynamic range of the SI ADM combined with the SI filter is greater than 40dB. This mixed-mode 1C, operating with a 3.3V supply voltage, was fabricated by a 1.5-μm singlepoly single-metal CMOS process. The whole system has been tested using human voice and results show that it is highly suitable for low-cost speech applications. Adaptive delta modulation. Low-cost speech recorder. Mixed-mode 1C, Switched-current design

Original languageEnglish
Pages (from-to)367-374
Number of pages8
JournalIEE Proceedings: Circuits, Devices and Systems
Issue number6
Publication statusPublished - 1997

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering


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