DC-DC Converter PWM Continuous On-State Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
DC-DC converters face inefficiencies in power conversion when input voltage drops, leading to increased flow-through currents and limited input voltage range for achieving desired output voltages, especially when operating in PWM/PFM switching systems.
Innovation Solution
A DC-DC converter configuration that employs continuous on-state operation of the driving switching element under PWM control when the output voltage is lower than a desired level, using a second comparator to extend on-time and prevent frequent switching, thereby improving power efficiency and widening the input voltage range for desired output voltage generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PWM control is used, then output voltage control precision is good, but when input voltage is low, the input voltage range for achieving desired output voltage is limited
Solution Approach 1:
The system dynamically adjusts its control strategy based on input voltage levels. For high input voltages, PWM control provides precise output voltage regulation. When input voltage drops below a threshold, the system switches to continuous conduction mode, which maintains the ability to achieve desired output voltages across a broader input voltage range, thereby enhancing adaptability without sacrificing control precision in either operating region
2Measurement precision
If switching frequency is increased to maintain output voltage, then output regulation is improved, but power efficiency deteriorates due to increased flow-through current
Solution Approach 1:
The patent uses periodic PWM switching at high input voltages to maintain precise output voltage regulation. When input voltage becomes low, it transitions to continuous conduction mode with reduced or eliminated switching, thereby reducing flow-through current and power losses while still maintaining adequate output regulation through continuous energy transfer, thus resolving the trade-off between regulation precision and power efficiency
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 approach reduces flow-through currents and enhances power efficiency by maintaining the driving switching element in an on-state when input voltage is low, allowing for a broader input voltage range to achieve desired output voltages, thereby improving power conversion efficiency.
Implementation Method 1
a driving switching element for performing switching to a flow path to flow an electric current through the inductor
Data Source
AI summary
A DC-DC converter including, an inductor; and a driving switching element for performing switching to a flow path to flow an electric current through the inductor; wherein the DC-DC converter drives the driving switching element by PWM control using a PWM control pulse to convert a direct-current input voltage supplied from a direct-current power source and to output a direct-current voltage having a piece of electric potential different from that of the direct-current input voltage, and wherein the DC-DC converter drives the driving switching element by the PWM control under a first condition, and the DC-DC converter makes the driving switching element be in an on-state continuously while the output direct-current voltage is lower than a desired level under a second condition.