Split-Pass LDO Regulation for High-Current DAC Supply Rails
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Solution Overview
Problem
As electronic devices become smaller, the reduced operating voltage leads to increased current requirements, necessitating high-current low-voltage regulation to maintain power output, which is challenging for digital-to-analog converters (DACs) in RF communications and other components, especially in scaling down components like transistors and conductors.
Innovation Solution
The implementation of a power management unit (PMU) with a buck converter and low-dropout regulator (LDO) that includes multiple pass devices to split voltage and current regulation, utilizing multiple low-dropout regulators (LDOs) to independently regulate in-phase (I) and quadrature (Q) signals, reducing crosstalk and enabling smaller pass devices while maintaining effective power handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single pass device is used for power regulation, then the device structure is simple, but it cannot provide sufficient high-current low-voltage regulation capability
Solution Approach 1:
The patent divides the single pass device into multiple parallel pass devices (first pass device and second pass device). Each pass device handles a portion of the total current, enabling high-current low-voltage regulation capability while keeping individual device sizes manageable. The multiple pass devices are controlled by amplifiers that regulate their respective outputs based on feedback signals.
2Volume of moving object
If component size is reduced for scaling, then device compactness is improved, but voltage regulation capability deteriorates
Solution Approach 1:
The patent uses multiple smaller pass devices in parallel to achieve the required total power handling capability. Each pass device is sized appropriately for its portion of the load, allowing compact individual components while maintaining overall high-current low-voltage regulation capability through parallel operation.
Solution Approach 2:
The patent combines multiple pass devices with multiple amplifiers in a parallel configuration. The amplifiers work together to regulate the outputs of the pass devices, merging their individual regulation capabilities to achieve the required overall voltage regulation performance for high-current low-voltage applications.
3Power
If multiple pass devices are used for high-current regulation, then power handling capability is improved, but crosstalk between signals increases
Solution Approach 1:
The patent divides the signal paths into separate branches, each handled by dedicated pass devices and amplifiers. The in-phase (I) signal and quadrature (Q) signal are processed through separate regulation paths, reducing interaction and crosstalk between signals while maintaining high current handling capability through parallel operation.
Solution Approach 2:
The patent implements independent regulation for different signal paths using separate amplifiers and pass devices. Each regulation loop is optimized for its specific signal requirements, providing localized control that minimizes interference and crosstalk between different signal channels while maintaining overall system performance.
Data Source
AI summary
The present disclosure relates to power management for digital-to-analog converters (DACs). As electronic devices and the components therein become increasingly smaller to satisfy the desire for more compact/portable devices, the operating voltage may be reduced to reduce the likelihood of shorts and/or voltage/current bleeds. To maintain comparable power output with the reduced operating voltage, the current may increase proportionally to the decrease in voltage. Consequently, in scaled devices and applications, high-current low-voltage regulators may be beneficial. As such, a low-dropout regulator (LDO) including one or more operational amplifiers and multiple pass devices may be implemented between a power supply and the DAC to regulate the power supply to the DAC. Moreover, the LDO may include one or more feedback loops to maintain a desired voltage regulation of the pass devices.