State-dependent ADC scheme for digitally isolated SMPC

Abstract

This paper proposes a state-dependent Analog-to-Digital Conversion (ADC) scheme for digitally isolated Switched Mode Power Converters (SMPCs). The SMPC voltage range is subdivided into three different regions corresponding to the three different states the SMPC can be in: steady state and the two transient states "undershoot" and "overshoot". Each state uses a different, optimised ADC transfer function where the steady state region is sampled with higher resolution than the transient regions. This scheme reduces the number of bits to be transferred across the isolation barrier and therefore accommodates the use of data couplers with lower bandwidth or increased switching frequency.