Design of integrated multi-mode reference voltage generator for SAR ADC

Abstract

Aiming at the problems of complex supply voltage and high sensitivity of power in ADC for the industrial Internet of Things, this paper presents a flexible, low power and low noise reference voltage generator for the SAR ADC to obtain good PSRR and a stable supply-independent full-scale range. The 2.5 V or 1.5 V is available based on the different range of supply voltage(2.65 V～3.6 V or 2.2 V～3.6 V). This circuit support off-chip capacitor to provide transient current for the ADC to avoid the power-hungry integrated buffer in series sampling mode. An energy-efficient mode which uses integrated buffer rather than off-chip capacitor can be configured to obtain short setting time to save energy during each one-shot sample. Testing result shows the circuit can save power/energy with no loss in ADC performance.

Keywords

• ADC
• reference voltage generator
• power
• energy