Load Independent Voltage Regulator Current Feedback Circuit
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Solution Overview
Problem
Conventional low-dropout voltage regulators require a sense pin to compensate for voltage drops due to resistances in the circuit, leading to increased size and complexity, and suffer from poor load regulation as output voltage varies with load current.
Innovation Solution
A load-independent voltage regulator with a current feedback circuit that uses a ratio of transistor sizes to generate a correction current proportional to the load current, minimizing voltage variations by compensating for series resistance without the need for a sense pin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sense pin is used to compensate for voltage drops, then output voltage regulation is improved, but device complexity and package size increase
Solution Approach 1:
The patent extracts the voltage compensation function from a separate sense pin configuration and integrates it directly into the existing power-out pin circuitry. The current feedback circuit uses the same power-out pin to sense and compensate for voltage drops, eliminating the need for an additional sense pin while maintaining voltage regulation accuracy.
Solution Approach 2:
The patent combines the voltage sensing and compensation functions with the existing power-out pin, merging multiple functions into a single pin. The power-out pin simultaneously provides power output and voltage feedback for compensation, reducing the total pin count and package complexity.
2Device complexity
If series resistance is present in the circuit, then voltage regulation is simplified, but output voltage stability deteriorates as load current varies
Solution Approach 1:
The patent implements a current feedback circuit that continuously monitors the load current through the series resistance and provides compensating current to counteract the voltage drop. The feedback mechanism uses the series resistance itself as part of the sensing path, converting the harmful voltage drop into useful feedback information for correction.
Solution Approach 2:
The patent creates a composite feedback mechanism that combines the series resistance (typically a harmful element) with the feedback circuitry to form a unified compensation system. The series resistance serves dual purposes: limiting current and providing feedback signal, transforming a detrimental component into a functional element of the regulation system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The current feedback circuit maintains a constant output voltage across varying load currents, reducing the impact of series resistance and eliminating the need for a sense pin, thereby simplifying the IC package and improving load regulation.
Implementation Method 1
A load independent voltage regulator with a current feedback circuit that uses a ratio of transistor sizes to mirror and divide the load current
Data Source
AI summary
An integrated circuit package (202) includes a voltage regulator (208) and a power-out pin (236) for coupling to a load circuit (210) via a connection (234) external to the integrated circuit package and for coupling to an output (230) of the voltage regulator via a connection (224, 228, 226 and 231) internal to the integrated circuit package. The internal connection has a series resistance that causes a voltage drop due to a load current. The voltage regulator compensates for the voltage drop in the internal connection using a current feedback circuit, in which the current fed back is proportional to the voltage drop caused by the series resistance of the internal connection.