Switching Regulator Feedback Signal Generation via Switching Node
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Modern switching regulators face challenges in generating a feedback signal without using the output voltage, requiring multiple control-in terminal PINs, and need to allow for external adjustment of the regulator output voltage.
Innovation Solution
A switching regulator design that generates a first feedback signal using a switching voltage signal, controlled by a resistor and capacitor connected between the switching node and the main controller, and optionally adjusts this signal using another capacitor, while also generating a second feedback signal from the output voltage using resistors and capacitors to allow external adjustment of the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a feedback signal is generated using the regulator output voltage, then the feedback control is accurate, but the control-in terminal PIN is occupied and cannot be used for other purposes
Solution Approach 1:
The feedback signal generation is segmented into two independent paths: one path uses the regulator output voltage through a control-in terminal PIN for accurate feedback control, while the other path generates a separate feedback signal using the switching voltage signal through a different terminal. This segmentation allows the main controller to receive feedback without occupying the control-in terminal PIN exclusively.
Solution Approach 2:
A resistor and capacitor are introduced as intermediary components to generate a feedback signal from the switching voltage signal. This intermediary mechanism creates an alternative feedback path that does not require direct connection to the control-in terminal PIN, thereby freeing up the terminal while maintaining feedback functionality.
2Device complexity
If the regulator output voltage is fixed, then the regulator operation is simple, but the output voltage cannot be externally adjusted to desirable levels
Solution Approach 1:
The regulator system is made dynamically adjustable by introducing external resistors that can be configured to change the feedback division ratio. This allows the output voltage to be adjusted to desirable levels while maintaining the core regulator operation simplicity through the same basic circuit structure.
Solution Approach 2:
The output voltage adjustment is achieved by changing the resistance values of external resistors connected to the feedback network. By varying these resistance parameters, the regulator output voltage can be externally adjusted to different desirable levels without fundamentally changing the regulator's operational mode or internal structure.
Data Source
AI summary
A novel method to generate a feedback signal in a switching regulator is presented. The method includes the generation of a first feedback signal using the switching signal. The first feedback signal carries a ripple and the ripple is in phase with the switching signal. The first feedback signal does not use a control-in terminal PIN. The voltage level of the first feedback signal is regulated through a resistor and a capacitor connected between the switching node and the switching regulator controller. In an alternative method, a second feedback signal is generated using the regulator output voltage. The controller receives the second feedback through a control-in terminal PIN. In the alternative method, another resistor and another capacitor are used to connect the first feedback signal and the second feedback signal. Furthermore, the second feedback signal can adjust the regulator output voltage through two resistors connected in series. The subject invention is designed to operate in the Continuous Conduction Mode (CCM) where the load is significant and the inductor current remains positive during the entire switching period. The method is presented for buck switching regulators, and can be utilized also for boost, buck-boost, flyback, forward, and sepic, etc.