Quasi-Resonant Power Controller Dynamic Delay Circuit
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Solution Overview
Problem
Conventional power controllers operating in quasi-resonant mode often experience suboptimal switching losses due to a fixed, constant delay time when turning on the power switch, which is not adaptable to the varying conditions of voltage valleys.
Innovation Solution
A power controller with a FB clamp circuit, peak hold circuit, valley detector, bottom finder, delay circuit, and maximum frequency limiter that dynamically adjusts the delay time based on the detection of voltage valley bottoms, allowing the power switch to be turned on at the optimal moment within each valley, minimizing switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a constant delay time is used to turn on the power switch after voltage valley detection, then the control method is simple, but the switching loss is not optimized
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed, constant delay time to a dynamic delay time that varies according to the actual voltage valley characteristics. The delay time is adjusted based on real-time detection of voltage valley depth and position, allowing the power switch to be turned on at the optimal moment within each voltage valley, thereby minimizing switching loss while adapting to changing operating conditions.
2Ease of operation
If the power switch is turned on at a fixed delay time after voltage valley start, then the control is easy to implement, but the energy efficiency is suboptimal
Solution Approach 1:
The patent implements feedback by continuously monitoring the voltage valley characteristics and using this information to adjust the delay time for power switch turn-on. The system detects the voltage valley start, evaluates the valley depth and timing, and feeds this information back to the delay circuit to optimize the turn-on moment, thereby improving energy efficiency while maintaining reasonable control complexity.
3Device complexity
If a fixed delay time is used for power switch turn-on, then the device structure is simple, but the switching loss optimization is insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the delay time parameter based on detected voltage valley characteristics. Instead of using a fixed delay time, the system dynamically adjusts the delay parameter according to the actual voltage valley depth and timing, enabling optimal switching loss reduction while maintaining a relatively simple device structure through parameter adaptation rather than structural complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This adaptive approach minimizes switching losses by ensuring the power switch is turned on at the bottom of voltage valleys, optimizing energy efficiency and reducing power consumption in quasi-resonant switched mode power supplies.
Implementation Method 1
voltage drop VAUX oscillates, substantially because of the resonant circuit substantially consisting of the primary winding PRM and any parasitic capacitors at the joint P
Data Source
AI summary
The disclosure provides a power controller and related control method for a switch mode power supply operating in a quasi-resonant mode. The switched mode power supply has a power switch and an auxiliary winding. The power controller has a feedback pin connected to the auxiliary winding. A clamp circuit is connected to the feedback pin and configured for clamping a voltage at the feedback pin by providing a clamp current. A peak hold circuit is connected to the clamp circuit for generating a peak record substantially corresponding to a peak value of the clamp current. A valley detector is configured for providing an entry signal indicating a start of a voltage valley. A delay circuit provides a trigger signal a delay time after the entry signal is provided. The delay time varies in response to the peak record, and the trigger signal is capable of turning on the power switch.