CAPACITIVE DIGITAL ISOLATOR CIRCUIT WITH ULTRA-LOW POWER CONSUMPTION BASED ON PULSE-CODING

摘要

A capacitive digital isolator circuit includes: a signal emitting module; a signal receiving module; and a capacitive isolation module. The signal emitting module includes an edge Pulse-Coding modulator circuit, which modulates an input signal to generate a pair of differential modulated signals based on the input signal and transmits the pair of differential modulated signals to the signal receiving module. Each of the pair of differential modulated signals has twelve high-frequency pulses when the input signal has a rising edge and has six high-frequency pulses when the input signal has a falling edge. The signal receiving module includes an ultra-low power consumption high-speed comparator, a timer and a pulse counter. An output signal of the pulse counter has a rising edge when the pulse number of the comparator output signal is larger than nine and a falling edge when the pulse number is equal to or smaller than nine.