US Patent 7528760 Class D analog-to-digital converter

A new analog-to-digital (ADC) circuit and architecture and the corresponding method of implementation are provided. The analog input signal is converted into a modulated pulse stream such as by a pulse-width-modulation scheme. The time-duration width of the pulses are measured by a TDC (time-to-digital converter) and converted to a digital binary representation that is directly correlated with the voltage amplitude of the analog input signal. The circuit implementation is substantially free of switches and circuit issues such as associated with sigma-delta and switched-capacitor techniques for ADC's.