Power Converter Oscillator Frequency Control
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Solution Overview
Problem
Existing power converter control circuits face challenges in responding effectively to middle or heavy loads, leading to poor output voltage response, unsuppressed ripples, and reduced conversion efficiency when the compensation voltage exceeds a certain threshold.
Innovation Solution
An oscillator with a compensation module and an oscillation module that adjusts the frequency of the gate control signal based on the compensation voltage, allowing the clock signal to be slowly varied with the load conditions, thereby improving the output voltage response and suppressing ripples while increasing conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the frequency of the pulse width modulation signal is fixed at a second fixed value when the compensation voltage is greater than the second predetermined voltage, then the device complexity is reduced, but the response of the output voltage to the load is poorer
Solution Approach 1:
The patent applies the dynamics principle by making the frequency of the pulse width modulation signal variable rather than fixed. When the compensation voltage is between the first predetermined voltage and the second predetermined voltage, the frequency varies with the compensation voltage. This dynamic frequency adjustment allows the control circuit to respond more effectively to load changes while maintaining manageable complexity through structured control logic.
2Device complexity
If the frequency of the pulse width modulation signal is fixed at a second fixed value when the compensation voltage is greater than the second predetermined voltage, then the device complexity is reduced, but the ripples of the output voltage cannot be suppressed
Solution Approach 1:
The patent applies the dynamics principle by implementing variable frequency operation based on compensation voltage levels. When the compensation voltage is between the first predetermined voltage and the second predetermined voltage, the frequency varies with the compensation voltage, which helps suppress output voltage ripples by adapting the switching frequency to load conditions, thereby improving output voltage stability.
3Device complexity
If the frequency of the pulse width modulation signal is fixed at a second fixed value when the compensation voltage is greater than the second predetermined voltage, then the device complexity is reduced, but the conversion efficiency of the power converter cannot be increased
Solution Approach 1:
The patent applies the dynamics principle by implementing variable frequency operation that adapts to load conditions through compensation voltage monitoring. When the compensation voltage is between the first predetermined voltage and the second predetermined voltage, the frequency varies with the compensation voltage, allowing the power converter to optimize its operating point and improve conversion efficiency by reducing energy losses under varying load conditions.
Data Source
AI summary
An oscillator applied to a control circuit of a power converter includes a compensation module and an oscillation module. The compensation module outputs or sinks an adjustment current according to a compensation voltage corresponding to a load, a direct current voltage of a primary side of the power converter, and a reference voltage. The oscillation module outputs a clock signal according to the compensation voltage, a control voltage, and the adjustment current. The control circuit generates a gate control signal to a power switch of the primary side according to the clock signal. When the compensation voltage is less than a first predetermined voltage, a frequency of the gate control signal is a first fixed value, and when the compensation voltage is between the first predetermined voltage and a second predetermined voltage and greater than the second predetermined voltage, the frequency is varied with the compensation voltage.