LDO Regulator with Zero Quiescent Current and Fast Transient Response
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Solution Overview
Problem
Prior art power supply control circuits for radio frequency power amplifiers in wireless communication devices face challenges in achieving both zero quiescent current and fast transient response, which are conflicting requirements, leading to inefficiencies, especially in low power conditions and wideband code division multiple access (WCDMA) modes.
Innovation Solution
A power supply control circuit comprising a buck/boost switcher circuit, a low drop out (LDO) regulator circuit, and a control signal circuit that dynamically turns on and off the LDO regulator based on the output voltage steady state conditions, ensuring zero quiescent current during steady states and enabling fast transient response when needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an LDO regulator is continuously operated to provide fast transient response, then transient response speed is improved, but quiescent current consumption increases
Solution Approach 1:
The LDO regulator is dynamically controlled to switch between active and inactive states based on load conditions. The control circuit monitors the power amplifier's operating state and activates the LDO only during transient conditions requiring fast response, while deactivating it during steady-state to eliminate quiescent current consumption.
Solution Approach 2:
The LDO regulator operates in periodic bursts rather than continuously. The control circuit periodically activates the LDO during transient events (such as power amplifier state changes) and deactivates it during steady-state periods, achieving fast response when needed while minimizing energy consumption overall.
2Reliability
If an LDO regulator is used with high voltage difference between input and output, then voltage regulation capability is improved, but efficiency deteriorates
Solution Approach 1:
A buck/boost switching regulator is introduced as an intermediary stage between the battery and the LDO regulator. This switching regulator handles the bulk voltage conversion with high efficiency, allowing the LDO to operate with minimal voltage difference between input and output, thereby maintaining both regulation capability and efficiency.
Solution Approach 2:
The voltage regulation function is segmented into two stages: a buck/boost switching regulator for gross voltage adjustment and an LDO regulator for fine voltage regulation. This segmentation allows each stage to operate in its optimal efficiency range, with the LDO handling only small voltage adjustments.
Data Source
AI summary
A system and a method are disclosed for providing a dynamically configured low drop out regulator that has zero quiescent current and a fast transient response. A power supply control circuit is provided that comprises a switcher circuit and a low drop out regulator and a control signal circuit. When the output voltage of the low drop out regulator is in a steady state condition the control signal circuit generates control signals that turn off the operation of the low drop out regulator to provide zero quiescent current. When the output voltage is not in a steady state condition the control signal circuit generates control signals that turn on the operation of the low drop out regulator to provide a fast transient response.