VDD-referenced sampling

• Main Authors: Shen Junhua, Coln Michael C. W
• Format: Patent
• Language: English
• Published: 30.05.2017
• Subjects: BASIC ELECTRONIC CIRCUITRY; CODE CONVERSION IN GENERAL; CODING; DECODING; ELECTRICITY

A voltage sampling circuit is provided that may directly connect a non-zero power supply voltage VDD to switching circuits during input voltage sampling, setting a common mode voltage without using reference voltages produced by a reference voltage generator circuit, and without requiring a common mode buffer circuit. The voltage sampling circuit may be used in an operational amplifier input stage such as for a pipelined ADC circuit, or in a comparator circuit. A SAR ADC circuit is also provided, comprising a control circuit, the voltage sampling circuit, a capacitor array, and a comparator circuit for comparing outputs occurring from charge redistributions. The voltage sampling circuit may enable increased power efficiency, avoid leakage concerns, and increase maximum input voltage swing. Reference plate switches in the voltage sampling circuit may include gate-boosted devices or thicker-oxide I/O devices. The devices may include n-channel field-effect transistors or high threshold voltage p-channel field-effect transistors.