Efficient technique for excess loop delay compensation in continuous-time ΔΣ modulators

A highly digital technique is proposed for excess loop delay (ELD) compensation in multi-bit continuous-time ΔΣ modulators. A digitally controlled reference switching matrix is used to replace the powerhungry signal adder and extra DAC driving the quantiser, which are commonly used in ELD compensation. With the proposed technique, the feedback DAC is embedded in the quantiser and implemented by a few switches. Thus, it allows low-voltage and low-power operation.