Hybrid analog-to-digital converter with multi-domain signal processing

An analog-to-digital converter comprising:

• a first converter stage configured for voltage domain quantization;
• a second converter stage configured for time-to-digital quantization, the second converter stage being coupled to the first converter stage to quantize a residual voltage of the voltage domain quantization;
• and
• an inter-stage converter disposed between the first and second converter stages, the inter-stage converter being configured to convert from a voltage domain to a time domain;
• wherein the inter-stage converter is configured to process the residual voltage of the voltage domain quantization such that a range of the residual voltage matches a full scale of the time-to-digital quantization, and
• wherein:
• the first converter stage comprises a continuous switching capacitor DAC (CDAC) and a voltage comparator;
• the inter-stage converter comprises a voltage-to-time converter (VTC), the VTC having an input coupled to the voltage comparator;
• the second converter stage comprises a Vernier-ring time-to-digital converter (TDC);
• and
• switching of the CDAC is timed by the Vernier-ring TDC so that the range of the residue signal of the first converter stage is equal to the full scale of the TDC.

An analog-to-digital converter comprising:

• a first converter stage configured for voltage domain quantization;
• a second converter stage comprising a Vernier-ring, time-to-digital converter (TDC) for time-to-digital quantization, the second converter stage being coupled to the first converter stage to quantize a residual voltage of the voltage domain quantization;
• and
• an inter-stage converter disposed between the first and second converter stages, the inter-stage converter being configured to convert the residual voltage from a voltage domain to a time domain;
• wherein the inter-stage converter is configured to process the residual voltage such that a range of the residual voltage of the voltage domain quantization matches a full scale of the time-to-digital quantization, and
• wherein a background calibration loop to align the range of the residue signal of the first converter stage with the full scale of the second converter stage.

An analog-to-digital converter comprising:

• a first converter stage configured for voltage domain quantization;
• a second converter stage comprising a Vernier-ring, time-to-digital converter (TDC), the second converter stage being coupled to the first converter stage to quantize a residual voltage of the voltage domain quantization;
• an inter-stage converter disposed between the first and second converter stages, the inter-stage converter being configured to convert the residual voltage from a voltage domain to a time domain;
• and
• a background calibration loop to align the range of the residue signal of the first converter stage with the full scale of the second converter stage.