Voltage Regulation Circuit High-Frequency PSRR Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Voltage regulation circuits, such as low dropout (LDO) regulation circuits, face a reduction in loop gain at high operating frequencies, leading to a decrease in power supply rejection ratio (PSRR), which affects the stability of the output voltage signal due to noise interference from the input voltage signal.
Innovation Solution
The proposed voltage regulation circuit includes an error amplifier, an output transistor, a noise extraction circuit, and a stabilization circuit. The noise extraction circuit extracts noise from the input voltage signal and converts it into a noise current signal, which is then used by the stabilization circuit to cancel interference in the high operating frequency range, thereby maintaining a high PSRR. Additionally, a buffer is used to increase the loop gain and adjust the pole based on the operating frequency, enhancing PSRR performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the operating frequency is increased, then the bandwidth is improved, but the loop gain is reduced and PSRR decreases
Solution Approach 1:
The noise extraction circuit separates the noise component from the input voltage signal by using a capacitor to bypass high-frequency noise to ground, allowing the main regulation circuit to focus on regulating the clean voltage component while the extracted noise is independently handled
Solution Approach 2:
The noise extraction circuit acts as an intermediary between the input voltage signal and the output, capturing and diverting high-frequency noise before it can affect the output voltage, thereby protecting the PSRR at high operating frequencies
2Reliability
If the loop gain is increased to improve PSRR, then the PSRR is improved, but the bandwidth is limited and operating frequency is reduced
Solution Approach 1:
The voltage regulation function is segmented into two independent paths: the main regulation path handles low-frequency voltage regulation through the error amplifier and output transistor, while the noise extraction path handles high-frequency noise through the capacitor, allowing each path to be optimized independently for its frequency range
3Speed
If the bandwidth is increased to improve operating frequency response, then the operating frequency is improved, but the loop gain is reduced
Solution Approach 1:
The high-frequency noise component is extracted and bypassed through the capacitor connected from the output to ground, removing it from the feedback loop before it can reduce the effective loop gain, allowing the main regulation circuit to maintain high loop gain for low-frequency signals while the bandwidth extends to high frequencies
Data Source
AI summary
A voltage regulation circuit is provided. The voltage regulation circuit includes an error amplifier, an output transistor, a noise extraction circuit, and a stabilization circuit. The error amplifier provides a control signal in response to changes in a feedback voltage. The output transistor receives an input voltage signal, and adjusts an output voltage signal at an output terminal of the voltage regulation circuit in response to the control signal and the input voltage signal. The noise extraction circuit extracts a noise of the input voltage signal to provide a noise current signal. The stabilization circuit converts the noise current signal into a stable signal. In a high operating frequency range, the stabilization circuit provides the stable signal to a control terminal of the output transistor to cancel interference caused by the noise of the input voltage signal.