LDO Leakage Blocking Circuit Using Comparator-Controlled Transistors
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Solution Overview
Problem
Low-dropout regulators in electronic devices face challenges in blocking power leakage, particularly at ultra-low voltages and across process corners and temperature variations, leading to significant leakage currents that affect device performance and efficiency.
Innovation Solution
A circuit design incorporating a pair of transistors with their gates controlled based on a comparison between input and output voltages, using a high-side comparator and leakage track bias generator to ensure only one transistor is on at a time, effectively blocking leakage currents by routing current through one transistor while blocking the path between input and output voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional LDO regulator design is used, then the regulator can operate with supply voltage close to output voltage, but significant leakage current occurs due to uncertain voltage conditions and temperature variations
Solution Approach 1:
The patent divides the single transistor into two separate transistors (first transistor and second transistor) with各自独立的 bulk connections. This segmentation allows independent control of each transistor's bulk voltage, enabling selective activation based on voltage comparison results, thereby reducing leakage current while maintaining LDO functionality
Solution Approach 2:
The patent introduces a comparator as an intermediary component that compares the supply voltage and output voltage to determine which transistor should be active. This intermediary enables intelligent control of the transistor pair, activating only one transistor at a time based on voltage conditions, thus blocking leakage paths while preserving the low-dropout characteristic
2Loss of energy
If transistor bulk voltage is not properly controlled, then circuit operation is simplified, but leakage current increases significantly near threshold voltages
Solution Approach 1:
The patent implements a feedback mechanism where the comparator continuously monitors the voltage difference between supply and output, and this comparison result feeds back to control the gate voltages of the transistor pair. This feedback ensures that the appropriate transistor remains active based on real-time voltage conditions, effectively blocking leakage current while maintaining automatic adaptation to varying operating conditions
Data Source
AI summary
In certain aspects, a circuit for power leakage blocking can include a voltage generation circuit that includes an amplifier connected at a negative input to a reference voltage and providing an output to a gate of a first transistor. A drain voltage of the first transistor can be fed back to a positive input of the amplifier. The voltage generation circuit can receive a first voltage at a source of the first transistor. The voltage generation circuit can supply a second voltage at a drain of the first transistor. The circuit can further include a pair of transistors. The pair of transistors can include a second transistor and a third transistor. Respective bulks of the pair of transistors can be connected to a bulk of the first transistor. The gates of the pair of transistors can be controlled according to a comparison between the first voltage and the second voltage, such that only one of the pair of transistors is on at a time.