LDO Regulator with Segmented Conduction Paths for USB Type-C
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Solution Overview
Problem
USB Type C devices require a low-dropout voltage regulator capable of generating a fixed supply voltage from multiple and varying power sources, including high and low voltages, while minimizing bulk and efficiently managing different supply voltages.
Innovation Solution
A low-dropout voltage regulator design utilizing a power PMOS transistor for high supply voltages and conventional PMOS transistors for lower voltages, featuring a selection circuit and error amplifier with multiple conduction paths and Miller compensation, allowing selection based on the lowest present voltage to ensure stable output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple conduction paths with different transistor types are used to handle various supply voltages, then the regulator can efficiently manage both high and low supply voltages, but the device bulk and structural complexity increase
Solution Approach 1:
The power stage is segmented into multiple conduction paths (first conduction path for high voltage, second conduction path for low voltage), each with its own output transistor optimized for specific voltage ranges. This segmentation allows the regulator to handle different supply voltages efficiently while maintaining a modular structure that manages complexity through functional division.
Solution Approach 2:
The selection circuit provides multi-functionality by automatically selecting the appropriate conduction path based on the detected supply voltage level. This universal control mechanism enables a single regulator device to adaptively handle both USB Type C high voltage mode (5-20V) and standard voltage mode (2.7-5.5V), making the device versatile across different operating conditions without requiring separate regulator designs.
2Reliability
If a power PMOS transistor is used for high supply voltage conduction paths, then the regulator can withstand high voltages up to 20 volts, but the device bulk increases
Solution Approach 1:
The regulator applies local quality by using power PMOS transistors specifically in the first conduction path where high voltage withstanding capability is required, while using conventional PMOS transistors in the second conduction path for low voltage operation. This localized application of specialized components ensures high voltage reliability only where needed, minimizing the overall device bulk by avoiding unnecessary use of larger power transistors throughout the entire circuit.
Solution Approach 2:
The regulator dynamically switches between different conduction paths based on the detected supply voltage level. When high voltage (5-20V) is detected, the selection circuit activates the first conduction path with the power PMOS transistor; when low voltage (2.7-5.5V) is detected, it activates the second conduction path with the conventional PMOS transistor. This dynamic adaptation allows the device to use the appropriate transistor type only when needed, effectively managing both high voltage capability and device size.
3Weight of stationary object
If conventional PMOS transistors are used for low supply voltage conduction paths, then the device bulk is reduced, but the regulator cannot efficiently handle high supply voltages
Solution Approach 1:
The power stage is segmented into two distinct conduction paths: the first conduction path uses a power PMOS transistor optimized for high voltage (5-20V) operation, while the second conduction path uses a conventional PMOS transistor optimized for low voltage (2.7-5.5V) operation. This segmentation allows each transistor type to be used only where it is most effective, reducing overall device bulk by avoiding the need to size all transistors for high voltage while maintaining full high voltage handling capability through the dedicated first conduction path.
4Adaptability or versatility
If the regulator is designed to accept multiple supply voltage inputs, then it can be supplied by various power sources including USB Type C and battery, but the circuit complexity increases
Solution Approach 1:
The selection circuit acts as an intermediary between the multiple power supply inputs and the rest of the regulator circuitry. It detects the supply voltage level and automatically selects the appropriate conduction path, isolating the complex multi-voltage input handling from the core regulation function. This intermediary approach enables multiple power source compatibility (USB Type C high voltage mode, USB Type C standard mode, battery) while containing circuit complexity within the modular selection circuit rather than propagating it throughout the entire regulator.
Data Source
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AI summary
Low drop voltage regulation device, comprising an error amplifier (AE) and a power stage (ETP) having an output terminal (BS) looped back to the error amplifier (AE) and capable of delivering an output current into a load (RL, CL).The device includes several main power inputs (EALPi) intended to potentially receive several different supply voltages respectively, in that the power stage (ETP) includes several conduction paths (PTHi) respectively connected between said main power inputs and said output terminal, individually selectable and each comprising an output transistor (MPgi), in that it further includes a selection circuit (CSL) connected to said main power inputs and configured to select one of the conduction paths (PTHi) according to a selection criterion, and in that the error amplifier (AE) includes an output stage (ETS) configured to selectively drive the output transistor (MPgi) of the selected conduction path.