Voltage Regulator Circuit with External Heat Dissipation
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Solution Overview
Problem
Existing DC voltage regulators face challenges in managing power dissipation, leading to high heat generation, especially when the unregulated voltage supply varies widely, which is problematic for integrated circuit implementations due to difficulties in heat dissipation.
Innovation Solution
A DC voltage regulating circuit with a primary current path and a bypass current path, featuring a voltage dropping heat dissipating impedance element externally located, and secondary pass elements to optimize heat dissipation by controlling the impedance of pass elements in response to output and node voltages, allowing for efficient heat management across varying input voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the unregulated voltage supply increases, then the power dissipated by the pass element increases, but the heat dissipation capability of integrated circuits remains limited
Solution Approach 1:
The patent extracts the heat dissipation function from the integrated circuit die by placing a voltage dropping resistor externally in series with the pass element. This external resistor carries a portion of the load current and dissipates power externally, removing the heat generation burden from the integrated circuit package where heat dissipation is difficult.
Solution Approach 2:
The patent introduces an external voltage dropping resistor as an intermediary element between the unregulated voltage supply and the integrated circuit voltage regulator. This intermediary component handles the power dissipation that would otherwise occur within the pass element, acting as a mediator to protect the integrated circuit from excessive heat generation.
2Temperature
If an external voltage dropping resistor is added to reduce heat dissipation in the pass element, then heat dissipation is improved, but the dropout voltage increases
Solution Approach 1:
The patent employs dynamic control of the external voltage dropping resistor's impedance through a control circuit that responds to the unregulated voltage supply level. When the unregulated voltage is high, the resistor dissipates more power externally; when the unregulated voltage approaches the dropout threshold, the control circuit adjusts the resistor's impedance to minimize its voltage drop, ensuring the regulator maintains regulation down to the minimum dropout voltage.
Solution Approach 2:
The patent changes the impedance parameter of the external voltage dropping resistor dynamically based on the operating conditions. The control circuit monitors the unregulated voltage supply and adjusts the resistor's impedance to optimize the balance between external power dissipation and maintaining adequate voltage headroom for regulation, thereby managing both heat dissipation and dropout voltage characteristics.
3Reliability
If the pass element impedance is controlled to maintain output voltage, then the output voltage regulation is improved, but the power dissipation and heat generation increase
Solution Approach 1:
The patent segments the power dissipation function between two components: the external voltage dropping resistor and the integrated circuit pass element. The external resistor handles the majority of power dissipation when the unregulated voltage is high, while the pass element maintains voltage regulation with minimal power dissipation. This segmentation allows the system to achieve both good voltage regulation and reduced overall power dissipation.
Solution Approach 2:
The patent uses feedback control where the control circuit monitors the output voltage and the unregulated voltage supply level to dynamically adjust the external voltage dropping resistor's impedance. This feedback mechanism ensures that the pass element maintains proper voltage regulation while the external resistor compensates for excess power dissipation, optimizing the balance between regulation performance and heat management.
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
This solution optimizes power and heat dissipation, enabling the voltage regulator to operate effectively across a wide range of unregulated input voltages with reduced heat generation both internally and externally, improving thermal management and extending the tolerance for integrated circuit loads.
Implementation Method 1
the power dissipated by the pass element 7 is equal to the product of the load current Il by the voltage drop across the pass element... the power dissipated by the pass element 7 is dissipated as heat
Data Source
AI summary
A voltage regulator receives an unregulated DC input voltage supply and provides a regulated DC output voltage. A primary pass element and an external resistor are located in a primary current path through which a load current flows from the input terminal to the output terminal. The voltage regulator includes two control circuits that control the impedances of two pass elements. Power dissipation can be improved and the dropout voltage can be reduced by maintaining the voltage on an internal node of the voltage regulator.