Power Supply Loop Stability via PWM Feedback
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Solution Overview
Problem
Conventional switching regulators exhibit poor loop stability due to wide load variations, affecting their performance in switching power supplies.
Innovation Solution
A power supply system with a stable loop is designed, incorporating a pulse width modulation driver, PMOS and NMOS transistors, a comparator, voltage control circuit, and current-limiting protection circuit to maintain loop stability by adjusting resistance values and controlling current states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional switching regulators are used with simple circuit structure, then device complexity is reduced, but loop stability deteriorates under wide load variation
Solution Approach 1:
The patent implements a feedback mechanism where the comparator detects the relationship between reference voltage and divided output voltage, and adjusts the control signal to the PWM driver accordingly. This closed-loop feedback system automatically compensates for load variations, maintaining loop stability without requiring complex circuit structures. The feedback path includes the comparator, voltage dividing unit, and PWM driver, forming a stable control loop.
Solution Approach 2:
The patent changes the operating parameters of the switching regulator by dynamically adjusting the duty cycle through PWM control based on feedback. The voltage dividing unit adjusts the feedback voltage parameter, and the comparator processes this parameter change to generate appropriate control signals, enabling the system to adapt to load variations and maintain stability through parameter optimization rather than complex circuitry.
2Adaptability or versatility
If conventional switching regulators operate under wide load variation, then adaptability is improved, but secondary pole variation increases causing poor loop stability
Solution Approach 1:
The feedback mechanism continuously monitors the output voltage through the voltage dividing unit and compares it with the reference voltage. When load variations cause secondary pole shifts, the feedback loop detects the resulting voltage deviations and adjusts the PWM duty cycle accordingly, compensating for the pole variations and maintaining loop stability across wide load ranges.
Solution Approach 2:
The patent introduces dynamic adjustment capabilities through the PWM driver and comparator system. The control parameters are dynamically changed in response to load variations, allowing the system to adapt its operating point in real-time. This dynamic control compensates for the shifting secondary poles, maintaining stability despite wide load variation and enhanced adaptability.
Data Source
AI summary
The invention relates to the field of power and electronic technologies, particularly to a power supply system with a stable loop comprising a PMOS transistor, a NMOS transistor, a first comparator and a voltage control circuit connected between a comparison terminal and the ground; wherein, a current-limiting acquisition port is configured to acquire on-state current of the PMOS transistor; and the current-limiting protection circuit outputs an voltage signal of the comparison result as the control signal of the pulse width modulation driver when the acquired on-current state of the PMOS transistor is less than a preset current value; and outputs a turn-off signal for turning off the pulse width modulation driver as the control signal when the acquired on-current state of the PMOS transistor is greater than a preset current value. The present invention has the advantages that relatively high loop stability can be ensured and high reliability is achieved.