Instant-On Power Supply Using Segmented LDO and Switching Regulators
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Solution Overview
Problem
Existing power supply systems for wearables face inefficiencies due to the need for power multiplex switches and linear regulators, which result in significant power wastage and increased chip area when providing instant-on functionality, especially when battery voltage is low.
Innovation Solution
Implementing a system with separate low dropout (LDO) regulators for instant-on voltages and switching regulators powered by the battery, allowing the LDO regulators to take over during low battery voltage and switching regulators to take over when the battery is charged, eliminating the need for power bypass switches and reducing power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If power multiplex switches and single LDO regulators are used to provide instant-on functionality, then the device can operate immediately when connected to a charger, but significant power is wasted and chip area increases
Solution Approach 1:
The power supply system is segmented into multiple independent voltage regulation paths: one LDO regulator dedicated to instant-on functionality and multiple switching regulators for normal operation. This segmentation allows each regulator to operate independently based on battery voltage conditions, eliminating the need for power multiplex switches and reducing power wastage during voltage switching operations.
Solution Approach 2:
The system dynamically selects between LDO regulator and switching regulators based on real-time battery voltage monitoring. When battery voltage drops below the required instant-on voltage threshold, the LDO regulator is automatically activated to maintain instant-on capability. This dynamic switching based on voltage conditions optimizes power efficiency while maintaining instant-on functionality.
2Adaptability or versatility
If power multiplex switches are used to switch between battery and charging source, then power can be supplied from alternative sources, but chip area increases significantly
Solution Approach 1:
Instead of using a single power multiplex switch to handle all voltage rail switching, the system segments the power supply into independent regulation paths. Each voltage rail has its own dedicated LDO or switching regulator, eliminating the need for complex power multiplex switching circuitry and significantly reducing chip area while maintaining the ability to adapt to different power sources.
Solution Approach 2:
The LDO regulator is designed to universally handle instant-on voltage regulation regardless of whether power comes from the battery or charging source. This multi-functional approach eliminates the need for source-specific switching mechanisms, reducing chip area while maintaining adaptability to different power sources.
3Adaptability or versatility
If step-down voltage conversion is implemented for each instant-on voltage from the charging source, then the required voltages can be supplied, but power efficiency decreases significantly
Solution Approach 1:
The voltage regulation system is segmented into dedicated LDO regulator for instant-on voltages and switching regulators for other voltages. This segmentation eliminates the need for multiple step-down conversions from the charging source, as the LDO regulator can directly provide instant-on voltages from either battery or charging source without significant power loss.
Solution Approach 2:
The LDO regulator acts as an intermediary between the power sources (battery or charging source) and the instant-on voltage rails. It mediates the voltage transition efficiently, converting input voltage to required instant-on voltages with minimal power loss, regardless of whether the input comes from battery or charging source.
Data Source
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AI summary
In an embodiment, a system includes voltage sensing logic to determine a first source voltage V first source corresponding to a first source, and a controller to receive an indication of V first source from the voltage sensing logic. The controller is to, responsive to V first source > a first output voltage (V1), select a first source first regulator to input V first source and provide V1; responsive to V first source > a second output voltage (V2), select a first source second voltage regulator that inputs V first source, and provide V2; responsive to V first source ≤ V1, select a second source first voltage regulator that inputs a second source voltage V second source that corresponds to a second source and is substantially constant in time where V second source > V1, and provide V1 independent of the first source first regulator and the first source second voltage regulator. Other embodiments are described and claimed.