Voltage Regulator Virtual Remote Sensing
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Solution Overview
Problem
Existing voltage regulators struggle to accurately compensate for voltage drops along long lines connecting the regulator to the load, especially when line resistance is unknown or varies due to temperature or connector instabilities, leading to inaccurate regulated voltage delivery.
Innovation Solution
The implementation of virtual remote sensing, where the regulator modulates its output current or voltage by a fractional amount to detect the voltage drop, scales this change to derive the actual line voltage drop, and adjusts its output to compensate for it, using a load capacitor to isolate the measurement from load resistance and minimize ripple effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional remote sensing with long voltage sense cables is used, then voltage drop compensation is achieved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the voltage drop measurement function from the traditional remote sensing approach. Instead of using separate sense cables to measure voltage at the load, the invention measures the voltage drop indirectly by detecting the relationship between current and voltage at the regulator output, then calculates the compensation needed. This eliminates the need for long sense cables and associated circuitry.
Solution Approach 2:
The patent introduces an intermediary measurement approach where a sense resistor is used to measure current, and this current measurement is combined with voltage measurements to derive the voltage drop. The controller acts as an intermediary that processes these measurements and calculates the compensation value, avoiding direct voltage measurement at the remote load location.
2Ease of manufacture
If prior knowledge of line resistance is used for compensation, then compensation circuit can be implemented, but accuracy is limited due to temperature and connector variations
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously measures the actual voltage at the regulator output and the current through the sense resistor, then uses this real-time data to calculate the actual voltage drop. This feedback loop allows the system to adapt to changing conditions such as temperature variations and connector instabilities, maintaining accuracy without requiring prior knowledge of line resistance.
Solution Approach 2:
The system performs self-measurement of its own operating conditions. The controller measures the voltage and current at the regulator output using built-in measurement circuits, calculates the voltage drop based on these self-measured values, and adjusts the output accordingly. This eliminates the need for external calibration or prior knowledge of line resistance.
3Measurement precision
If regulator output voltage is increased to compensate for voltage drop, then load voltage is maintained, but regulator output current increases causing additional power loss
Solution Approach 1:
The patent applies partial compensation rather than full compensation for the measured voltage drop. The controller calculates the voltage drop and applies a compensation value that is a fraction of the measured drop, typically 50-70%. This partial action approach maintains load voltage within acceptable tolerances while avoiding the excessive power loss that would result from fully compensating for the entire voltage drop.
Data Source
AI summary
An automatic voltage compensation circuit in a voltage regulator compensates the output voltage for a voltage drop along lines leading to a remote load. A load capacitor is connected across the load for providing a low impedance across the load during a test phase of the regulator. In one embodiment, during the test phase, the load current is changed up or down a small percentage (e.g., 10%). As a result, the regulator voltage changes due only to the line resistance since the load is bypassed by the load capacitor. The voltage drop at full load current is then derived by detecting the change in regulator output voltage (a fractional voltage drop) and multiplying it. The normal mode is resumed, and the derived voltage drop is added to the regulator output by either compensating the feedback loop or by adding the voltage drop to the output of the regulator.