Automatic Oscillator Frequency Switching for Stable SMPS Output
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Solution Overview
Problem
Current DC power supplies face instability and reduced energy conversion efficiency under variable load conditions due to instability in feedback voltage and high quiescent current, especially when switching between linear and pulse-frequency modulation regulators.
Innovation Solution
The implementation of automatic frequency oscillator circuits in switch-mode power supplies that generate fixed frequency pulses under heavy loads and variable frequency pulses under light to moderate loads, ensuring stable average output voltages and low quiescent currents by adjusting frequency based on load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a switching regulator is used to improve energy conversion efficiency, then energy efficiency is improved, but feedback voltage instability occurs under variable load conditions
Solution Approach 1:
The patent implements a dynamic frequency adjustment mechanism where the oscillator automatically changes its operating frequency based on detected load conditions. Under light load conditions, the frequency is reduced to minimize quiescent current consumption, while under heavy load conditions, the frequency increases to maintain stable feedback voltage and improve energy conversion efficiency. This dynamic adaptation resolves the contradiction by allowing the system to optimize both efficiency and stability according to real-time operating conditions.
Solution Approach 2:
The patent changes the operating frequency parameter of the oscillator based on load conditions to simultaneously achieve stable feedback voltage and high energy efficiency. The system monitors load current and adjusts the switching frequency accordingly, transforming a fixed-parameter system into a variable-parameter system that can adapt to different operating scenarios, thereby resolving the stability-efficiency trade-off.
2Use of energy by stationary object
If the oscillator frequency is reduced under light load conditions to reduce quiescent current, then quiescent current is reduced, but feedback voltage instability may occur
Solution Approach 1:
The patent implements variable frequency operation where the oscillator frequency is dynamically adjusted based on load conditions. Under light load conditions, the frequency is reduced to minimize quiescent current consumption while maintaining feedback voltage stability through careful frequency selection. The system monitors feedback voltage stability and adjusts frequency accordingly, allowing the same circuit to achieve both low quiescent current and stable operation by changing its operating parameter.
3Device complexity
If a fixed-frequency oscillator is used to simplify circuit design, then device complexity is reduced, but energy conversion efficiency decreases under variable load conditions
Solution Approach 1:
The patent implements a self-regulating oscillator that automatically adjusts its own frequency based on detected load conditions without requiring complex external control circuits. The oscillator monitors the power supply's operating state and self-adjusts the switching frequency to optimize energy conversion efficiency across different load conditions. This self-service approach maintains relatively simple circuit design while achieving variable-frequency operation for improved efficiency.
Data Source
AI summary
In some examples, a switch-mode power supply circuit comprises a pulse generation circuit comprising an oscillator, the oscillator configured to generate first pulses using a fixed frequency regulation for a first load condition that exceeds a predefined threshold and configured to generate second pulses using a variable frequency regulation for a second load condition that does not exceed the predefined threshold. The circuit also includes a power converter coupled to the pulse generation circuit and configured to convert a first voltage to a regulated voltage using either one of the first or second pulses generated by the pulse generation circuit. The circuit further comprises an output filter coupled to the power converter and configured to produce a second voltage from the regulated voltage.