A 12-bit incremental ΣΔ ADC for battery management system in electric vehicles

In this paper, a 12-bit incremental sigma-delta (ΣΔ) analog to digital converter (ADC) for the lithium battery management system (BMS) in electric vehicles is presented. In order to reduce the power consumption and the required clock cycles in one conversion, a second order incremental ΣΔ architecture with single feedback loop is adopted for the modulator of the ADC. The ADC is designed with a 0.5μm BCD process under a power supply voltage of 5V and a sampling clock frequency of 1MHz. Measurement results show that only 512 clock cycles is required for the conversion of one battery voltage, with a maximum absolute conversion error of less than 3mV. The power consumption is less than 510mA and the chip area of the ADC is 500×800μm².