Split-Pass DAC Supply Regulation to Cut I/Q Crosstalk
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Solution Overview
Problem
As electronic devices become smaller, the reduced operating voltage leads to increased current demand, necessitating high-current low-voltage regulation to maintain power output, which is challenging due to space constraints and potential crosstalk between multiphase signals in DACs.
Innovation Solution
Implementing a power management unit with multiple low-dropout regulators (LDOs) and pass devices to split voltage regulation across independently-controlled LDOs, reducing current per device and mitigating crosstalk between I and Q signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single high-current pass device is used for voltage regulation, then power handling capability is maintained, but device size increases and crosstalk between multiphase signals occurs
Solution Approach 1:
The patent divides the single high-current pass device into multiple lower-current pass devices (first pass device and second pass device). Each pass device handles a portion of the total current, thereby maintaining overall power handling capability while reducing individual device current density. This segmentation also spatially separates the current paths, reducing electromagnetic crosstalk between multiphase signals.
2Area of moving object
If device size is reduced to meet space constraints, then area is decreased, but current density increases leading to regulation challenges
Solution Approach 1:
By segmenting the power regulation function across multiple pass devices, each device can be smaller in area while collectively handling the same total power. The current load is distributed among parallel pass devices, reducing individual current density and associated thermal and regulation challenges despite reduced individual device area.
Solution Approach 2:
Multiple pass devices are combined in a parallel configuration where each device contributes to the overall power regulation. The combined effect of multiple smaller devices achieves the same total current handling capability as a single larger device, while benefiting from reduced individual device area and improved current distribution.
3Object-affected harmful factors
If multiple independently-controlled LDOs are implemented, then crosstalk is reduced and pre-distortion is facilitated, but device complexity increases
Solution Approach 1:
The power regulation system is segmented into multiple independently-controlled LDOs, each with its own pass device and control circuitry. This segmentation enables independent optimization of each regulator channel, reducing inter-channel crosstalk and facilitating separate pre-distortion compensation for each phase while managing complexity through modular design.
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.