Programmable Current Feedback Network for LDO Voltage Tuning
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Solution Overview
Problem
Existing feedback networks for Low-Drop-Out (LDO) regulators require a large silicon substrate area and complex controller designs due to the number of resistance sets and switches needed for multiple output voltage values, leading to increased complexity and area usage.
Innovation Solution
Incorporating programmable current generators within the feedback network, which produce controlled currents that add to the output voltage, reducing the number of resistance sets required while maintaining a high number of available output voltage values, and allowing for digital control of these currents for finer tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a feedback network uses a chain of series-connected resistance sets and switches to provide multiple output voltage values, then the number of available output voltage values increases, but the silicon substrate area occupied by the feedback network increases
Solution Approach 1:
The patent changes the fundamental parameter from using discrete resistance sets and switches to using a single programmable current generator that can dynamically adjust its output current. This allows the same physical hardware to provide multiple output voltage values by changing the current parameter, thereby reducing silicon substrate area while maintaining adaptability for multiple voltage outputs.
Solution Approach 2:
The programmable current generator serves multiple functions: it replaces the entire chain of resistance sets and switches, provides coarse tuning through digital control, and enables fine tuning through programmable current adjustment. This single component performs what previously required multiple discrete components, reducing area while maintaining versatility.
2Adaptability or versatility
If a feedback network uses a chain of series-connected resistance sets and switches to provide multiple output voltage values, then the number of available output voltage values increases, but the controller design complexity increases
Solution Approach 1:
The patent simplifies controller design by changing from controlling multiple switches with complex logic to simply programming the current generator's output current. The controller only needs to adjust the current parameter digitally, which is a straightforward operation compared to coordinating multiple switches and managing their states, thereby reducing controller design complexity while maintaining adaptability.
Solution Approach 2:
The patent extracts the complex switch control logic and replaces it with a simpler programmable current control mechanism. By removing the need to control multiple switches and their combinations, the controller design becomes significantly simpler while the programmable current generator maintains the ability to provide multiple output voltage values.
3Measurement precision
If a feedback network uses more resistance sets and switches to provide more output voltage values, then the output voltage tuning precision increases, but the silicon substrate area increases
Solution Approach 1:
The patent achieves fine tuning precision without increasing area by using a programmable current generator that can adjust its output current in small incremental steps. This digital parameter control provides precise voltage tuning through current modulation, eliminating the need for additional discrete resistance sets and switches that would occupy more silicon substrate area.
Solution Approach 2:
The patent transitions from static discrete resistance values to a dynamic programmable current source. The current generator can continuously adjust its output to provide fine tuning precision, replacing multiple fixed resistance values with a single dynamic component that achieves the same tuning precision without occupying additional area.
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 approach significantly reduces the silicon substrate area occupied by the feedback network and simplifies the controller design, enabling a higher number of available output voltage values with reduced complexity, while providing both coarse and fine tuning capabilities for the LDO regulator output voltage.
Implementation Method 1
a first programmable current generator with a current output terminal which is connected to the intermediate node between both resistance subsets of the first resistance set of the chain, and the first programmable current generator is suitable for producing a controlled value of a current flowing at the current output terminal
Data Source
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AI summary
A feedback network (200) for Low-Drop-Out generator comprises a chain of series-connected resistance sets (1, 2,..., m), and a programmable current generator (210) which is connected to a node (11) intermediate between two resistance subsets (1D, 1'). A fine tuning of the feedback network is provided by the programmable current generator, while reducing the number of the resistance sets within the chain. Another programmable current generator (220) may also be provided for a trimming function of the feedback network.