Bidirectional Current LDO Circuit for Stable Output Voltage
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Solution Overview
Problem
Conventional low-dropout regulators are limited in their application scenarios due to their unidirectional current transfer capability, which restricts their ability to handle bidirectional current adjustments and maintain stable output voltages across a wider power supply voltage range.
Innovation Solution
A low-dropout regulator design that incorporates a voltage divider circuit, an operational amplifier, a regulator circuit, and an output circuit, enabling bidirectional current adjustment by generating regulated voltages and adjusting current differences to stabilize the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a P-type transistor is used as a pass transistor to control voltage, then the voltage can be limited, but the current transfer capability is unidirectional which limits application scenarios
Solution Approach 1:
The regulator is divided into multiple functional modules: voltage divider circuit for reference voltage generation, operational amplifier for error detection and amplification, regulator circuit for current control, and output circuit for bidirectional current adjustment. This segmentation allows each module to specialize in specific functions, enabling bidirectional current transfer capability while maintaining voltage regulation.
Solution Approach 2:
The patent implements dynamic bidirectional current adjustment by using the operational amplifier to dynamically control the regulator circuit based on the difference between reference voltage and output voltage. The system can automatically switch between sourcing and sinking current modes, transforming the static unidirectional transistor into a dynamic bidirectional system.
2Adaptability or versatility
If conventional LDO design is used, then the structure is simple, but the power supply voltage range support is limited
Solution Approach 1:
The operational amplifier serves multiple functions: it amplifies voltage errors, controls the regulator circuit, and enables bidirectional current adjustment. The voltage divider circuit provides both reference voltage generation and feedback signal division. This multi-functionality allows the regulator to support wider power supply voltage ranges without proportionally increasing overall system complexity.
Solution Approach 2:
The operational amplifier acts as an intermediary between the voltage divider circuit and the regulator circuit, translating voltage differences into control signals. This intermediary component enables precise control over the bidirectional current adjustment, allowing the system to handle wider voltage ranges while maintaining manageable complexity through layered control architecture.
3Reliability
If unidirectional current transfer is used, then the circuit is simpler, but the output voltage stability across different conditions is reduced
Solution Approach 1:
The voltage divider circuit continuously monitors the output voltage and feeds it back to the operational amplifier. The op-amp compares this feedback voltage with the reference voltage and dynamically adjusts the regulator circuit to maintain voltage stability. This closed-loop feedback mechanism ensures output voltage stability across varying load conditions and power supply voltages, with the complexity justified by the significant improvement in reliability.
Data Source
AI summary
A low-dropout regulator includes a voltage divider circuit, an operation amplifier, a regulator circuit and an output circuit. The voltage divider circuit divides a power supply voltage to generate a predetermined voltage. The operational amplifier generates a bias voltage according to the predetermined voltage and an output voltage of an output terminal. The regulator circuit generates a first regulated voltage and a second regulated voltage according to the bias voltage. The output circuit adjusts a difference between a first current and a second current according to the first regulated voltage and the second regulated voltage to regulate the output voltage.