Auto-Zeroing Voltage Compensation Circuit for Mobile PMICs
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Solution Overview
Problem
Mobile devices face increased voltage error rates as the desired operating voltage decreases, particularly due to offset voltages in semiconductor devices, which can impair the performance of power management integrated circuits (PMICs).
Innovation Solution
An electronic circuit with a compensation circuit that generates a compensation voltage based on a reference voltage and an output voltage, using multiple amplifying circuits to adjust and stabilize the voltage, thereby reducing error rates by canceling out offset voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the voltage level is decreased to operate semiconductor devices with lower power consumption, then power efficiency is improved, but the error rate of the voltage increases
Solution Approach 1:
The patent applies preliminary action by performing auto-zeroing calibration before the actual voltage conversion operation. The calibration mode pre-characterizes the offset voltages and non-linearity errors of the DAC and amplifier circuits, storing these error parameters for subsequent compensation during normal operation. This preliminary characterization enables accurate error correction even at low voltage levels where error rates would otherwise increase.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting compensation parameters based on the calibrated error characteristics. The system modifies the DAC output code by adding compensation values derived from calibration measurements, effectively changing the output voltage parameter to counteract inherent circuit errors. This parameter adjustment maintains voltage accuracy across different operating levels including low voltage conditions.
2Device complexity
If offset voltages are present in active elements of the electronic circuit, then device simplicity is maintained, but voltage accuracy deteriorates
Solution Approach 1:
The patent implements feedback by measuring the actual output voltage during calibration mode and using this feedback information to determine compensation parameters. The system feeds back the measured offset voltages and error characteristics into the compensation algorithm, which then adjusts the DAC output accordingly. This feedback mechanism maintains voltage accuracy without requiring complex circuit modifications to eliminate offset voltages.
Solution Approach 2:
The patent applies self-service by enabling the circuit to automatically calibrate and compensate for its own errors without external intervention. The auto-zeroing function allows the DAC and amplifier circuits to self-characterize their offset voltages and non-linearity errors, then self-correct these errors through computational compensation. This self-service approach maintains simplicity while improving accuracy.
3Device complexity
If a single amplifying circuit is used to generate compensation voltage, then device complexity is reduced, but compensation accuracy is insufficient
Solution Approach 1:
The patent applies segmentation by dividing the voltage generation and compensation function into multiple specialized amplifying circuits. The first amplifying circuit generates the basic compensation voltage based on calibration data, while the second amplifying circuit refines this compensation and combines it with the main signal. This segmentation allows each circuit to be optimized for specific tasks, achieving higher overall compensation accuracy than a single circuit could provide.
Data Source
AI summary
In one embodiment, the electronic circuit includes a first amplifying circuit configured to generate a first compensation voltage based on a first reference voltage and an output voltage. The output voltage is from a functional circuit bloc. A second amplifying circuit is configured to generate a control voltage based on an input voltage, a second reference voltage and the first compensation voltage. The second reference voltage is different than the first reference voltage.