Self-Adaptive LDO Circuit for Fast Load Response and Loop Stability
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Solution Overview
Problem
Existing LDO circuits face challenges in achieving fast response times while maintaining loop stability and adapting to load changes, leading to limitations in application scope.
Innovation Solution
A self-adaptive fast-response LDO circuit is designed with a band gap reference circuit, error amplifier, power transistor, and a self-adaptive acceleration response circuit, which includes acceleration charging and discharging circuits to mirror currents in preset ratios, enabling rapid charging and discharging based on differential input end unbalanced states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fast-response circuit is added to reduce response time, then the response speed is improved, but the circuit series and feedback capacitance increase, affecting loop stability
Solution Approach 1:
The patent implements a self-adaptive acceleration response circuit that dynamically adjusts the acceleration current based on the operating state of the LDO circuit. The circuit uses a control signal to selectively enable or disable the acceleration current path, allowing the system to switch between fast-response mode and stable operation mode. This dynamic adjustment resolves the contradiction by providing fast response only when needed while maintaining loop stability during normal operation.
2Productivity
If the circuit series and feedback capacitance are increased to accelerate signal establishment, then the adjusting speed is improved, but the loop stability is deteriorated
Solution Approach 1:
The patent changes the parameter of acceleration current from a fixed value to a variable parameter controlled by the operating state. The self-adaptive acceleration response circuit monitors the LDO's operation status and adjusts the acceleration current magnitude accordingly, enabling fast adjusting speed when required while preventing stability deterioration through controlled parameter adjustment.
3Loss of time
If a fixed fast response circuit is implemented, then the response time is reduced, but the circuit cannot adapt to load changes, limiting application scope
Solution Approach 1:
The patent implements a self-adaptive acceleration response circuit that automatically detects the LDO circuit's operating state and adjusts the acceleration current accordingly. The circuit uses feedback from the LDO's internal nodes to determine when acceleration is needed and how much acceleration current to provide, enabling the system to adapt to varying load conditions without external intervention and maintain optimal response time across different applications.
Data Source
AI summary
Disclosed are a self-adaptive fast-response LDO circuit and a chip thereof. Said circuit includes a band gap reference circuit, an error amplifier, a power tube, a feedback resistor network, and a self-adaptive acceleration response circuit. The current of the power tube is mirrored by means of the self-adaptive acceleration response circuit, such that the tail current of a differential circuit in the error amplifier can accelerate charging and discharging adaptively according to load changes of the LDO circuit. In addition, before the LDO circuit is stably balanced, the characteristics of unbalanced states of two differential input ends of the error amplifier are used to perform fast charging and discharging on the tail current of the differential circuit and a gate electrode of the power tube in an extremely short time, such that the response time of the LDO circuit is greatly reduced.