Digital Reference Voltage Generation for PVT Stability
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Solution Overview
Problem
Existing reference voltage circuits are sensitive to process-voltage-temperature (PVT) variations, making it challenging to maintain a stable output voltage in applications like low dropout regulators and DC-DC converters.
Innovation Solution
A reference voltage generating apparatus that includes a digital data generating circuit to convert an input reference voltage into digital control data and a converting circuit to generate a second reference voltage using the stored digital control data, with a comparator and counter circuit to calibrate the second reference voltage based on amplitude differences, ensuring stability across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional reference voltage circuit is used, then the circuit can generate a reference voltage, but the output voltage becomes sensitive to PVT variations and cannot be reliably maintained
Solution Approach 1:
The patent implements a feedback mechanism where the generated second reference voltage is continuously compared with the first reference voltage using a comparator. The comparator output feeds back to adjust the digital control data, which in turn adjusts the converting circuit to maintain voltage stability. This closed-loop feedback system compensates for PVT variations and ensures reliable output voltage maintenance.
Solution Approach 2:
The patent replaces the conventional analog reference voltage circuit with a digital-based system. The digital data generating circuit converts the first reference voltage to digital control data, and the converting circuit uses digital-to-analog conversion to generate the second reference voltage. This substitution of digital processing for analog circuitry reduces sensitivity to PVT variations and improves reliability.
2Reliability
If calibration operations are performed frequently to maintain voltage accuracy, then the reference voltage stability improves, but the power consumption increases
Solution Approach 1:
The patent implements periodic calibration operations controlled by a clock signal. The comparator and counter circuit operate at specific intervals defined by the clock frequency, rather than continuously. This periodic action maintains reference voltage accuracy through regular calibration while allowing the system to consume less power during non-calibration periods, thus resolving the contradiction between accuracy and power consumption.
Data Source
AI summary
A reference voltage generating apparatus, includes a digital data generating circuit configured to convert an input first reference voltage to digital control data and store the digital control data; and a converting circuit configured to generate a second reference voltage corresponding to the first reference voltage using the stored digital control data.