Programmable analog-to-digital converter for low-power DC-DC SMPS
AssigneeExar Corporation
InventorsAmir Parayandeh, Aleksandar Prodic
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Abstract
A voltage-to-time based windowed analog-to-digital converter (ADC) can have programmable reference voltage, conversion time, and accuracy of voltage regulation. The ADC can be fully implemented on a small silicon area and is suitable for implementation in various integrated digital controllers for high-frequency low-power switch-mode power supplies (SMPS). The programmable characteristics can be achieved through the utilization of the inherent averaging effect of the delay line or of the other voltage-to-time conversion structures and through the adjustments of delay cells' propagation times or the effective voltage-to-time conversion ratio in alternative structures.
Claims20
A circuit comprising:
- a sigma-delta DAC that receives a digital value and outputs an analog reference voltage output whose average is related to the digital value;
- and
- a windowed ADC converter including a reference voltage-to-time converter that is adjusted using the analog reference voltage output of the sigma-delta DAC and a measurement voltage-to-time converter that is adjusted using a system output voltage wherein the windowed ADC converter determines an error value and wherein the reference and the measurement voltage-to-time converters are a moving average filter.
A circuit comprising:
- a sigma-delta unit;
- and
- a second unit connected to an output of the sigma-delta unit, the second unit including a reference delay line and measurement delay line wherein an error decoder of the second unit produces an error signal that is derived from a number of delay cells that a clock signal passes through the measurement delay line in a time it takes for the clock signal to pass through a predetermined section of the reference delay line.
Dependencies are inferred from the claim text.