RF Circuit Bias Compensation for Supply Voltage Variation
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Solution Overview
Problem
Variations in supply voltage lead to degradation in performance of RF integrated circuits, particularly in gain, due to variations in polarization currents, and existing solutions like cascoding or using LDO regulators impose constraints on supply voltage values.
Innovation Solution
An integrated circuit with a polarization centralized circuit that performs open-loop compensation by adjusting a correction coefficient based on the sensitivity of the circuit to voltage variations, using a compensation circuit and current replication blocks to generate a corrected current, reducing the sensitivity of polarization currents to supply voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cascode current sources or LDO voltage regulator is used to eliminate supply voltage variations, then polarization current stability is improved, but supply voltage value is reduced which imposes constraints on the integrated circuit
Solution Approach 1:
The patent applies preliminary action by measuring the actual supply voltage and calculating the required polarization current adjustment before the circuit operates. The microcontroller computes the correction coefficient based on the measured voltage and stores it in a lookup table, so that when voltage variations occur, the already-prepared correction data can be immediately applied to maintain stable polarization currents without needing LDO regulators that would reduce the supply voltage.
2Reliability
If LDO voltage regulator is used to deliver stable supply voltage, then polarization current variation is reduced, but device complexity increases
Solution Approach 1:
The patent introduces a microcontroller as an intermediary that mediates between the supply voltage and the polarization current generation. Instead of using complex LDO regulator circuits, the microcontroller measures the supply voltage, calculates the appropriate correction coefficient, and controls the current sources accordingly. This software-based intermediary approach reduces hardware complexity while maintaining polarization current stability.
3Reliability
If centralized pre-compensation of polarization current is implemented, then sensitivity to supply voltage variations is reduced, but device complexity increases
Solution Approach 1:
The patent implements feedback by continuously measuring the actual supply voltage with an ADC, comparing it against reference values, and adjusting the polarization current based on the measured deviation. The microcontroller reads the supply voltage, determines the correction coefficient from the lookup table based on the measured voltage level, and applies this correction to the polarization current generation, creating a closed-loop feedback system that automatically compensates for voltage variations.
Data Source
AI summary
A method for polarizing at least one first electronic circuit based on a first direct polarization current, the at least one first circuit being powered by a supply voltage having actual values dispersed around a rated value, the at least one first circuit having at least one first physical parameter whose value could undergo a variation resulting from the dispersion of voltage values, the method comprising an open-loop compensation of the dispersion of the voltage value including elaborating a first corrected current based on a reference current and a first correction coefficient determined from the variation of the value of the at least one first physical parameter, resulting from the dispersion of the voltage values, and elaborating the first polarization current based on the first corrected current.