Switching Control Circuit for Smooth DC-DC Burst Mode Transitions
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Solution Overview
Problem
Current resonant DC-DC converters struggle to efficiently transition between normal and burst modes based on load states due to limitations in adjusting feedback voltage through circuit constants, affecting operation efficiency.
Innovation Solution
A switching control circuit that includes a comparator circuit, a first adjustment circuit, and a drive signal output circuit to dynamically control the ON periods of transistors in response to feedback voltage changes, allowing seamless transitions between normal and burst modes based on load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the feedback voltage is adjusted by changing circuit constants, then the operation of the DC-DC converter in burst mode can be changed, but it is difficult to change the feedback voltage and adjust the operation
Solution Approach 1:
The patent implements dynamic adjustment of the feedback voltage level by switching between multiple voltage levels (first voltage level and second voltage level) based on load conditions. The control circuit dynamically selects which voltage level to use for feedback comparison, enabling adaptive burst mode operation without complex circuit constant changes. This resolves the contradiction by making the system dynamically adjustable rather than statically fixed.
Solution Approach 2:
The patent changes the feedback voltage parameter from a fixed value to a multi-level adjustable value. By providing multiple voltage levels (first voltage and second voltage) that can be selectively applied to the feedback terminal, the system can adapt its burst mode operation characteristics. This parameter change approach allows easy adjustment of burst mode behavior through simple voltage level selection rather than complex circuit modifications.
2Productivity
If the switching control circuit transitions between normal mode and burst mode based on load state, then power supply efficiency is improved, but output voltage stability and noise control become challenging
Solution Approach 1:
The patent employs periodic action by implementing burst mode operation where the power supply alternates between active switching periods and idle periods based on load conditions. During light load conditions, the converter operates in burst mode with periodic on-off cycles, reducing switching frequency and improving efficiency. The control circuit monitors feedback voltage and transitions between normal continuous mode and periodic burst mode, maintaining output stability while optimizing efficiency through controlled periodic operation.
Solution Approach 2:
The patent uses feedback control by continuously monitoring the output voltage through the feedback terminal and comparing it against reference voltage levels. The control circuit adjusts its operation based on the feedback signal, transitioning between normal mode and burst mode to maintain output voltage stability. This feedback mechanism ensures that despite mode transitions, the output voltage remains stable and within specifications, resolving the reliability concern.
3Stability of the object's composition
If the ON period of transistors is gradually increased or reduced in burst mode, then smooth transitions between operating states are achieved, but response time and control precision are affected
Solution Approach 1:
The patent applies preliminary action by pre-defining multiple discrete voltage levels (first voltage level, second voltage level) that correspond to different operating states. Instead of continuously adjusting the feedback voltage during transitions, the system pre-prepares distinct voltage levels that can be quickly switched between. This allows for smooth transitions between normal mode and burst mode while maintaining fast response capability, as the control circuit can immediately switch between predefined voltage levels without gradual adjustment delays.
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
Enhances operational efficiency by maintaining output voltage stability and reducing noise and overvoltage risks during load state changes, optimizing power supply performance.
Implementation Method 1
a first capacitor that forms a resonant circuit with the primary coil
Data Source
AI summary
A switching control circuit for controlling a power supply circuit, including: a comparator circuit comparing each of a first voltage and a second voltage with a feedback voltage corresponding to an output voltage; a first adjustment circuit adjusting the first voltage; and a drive signal output circuit outputting a drive signal to operate the power supply circuit in a normal mode and in a burst mode, respectively in response to a state of the load entering a light-load state and a light-load state. The drive signal output circuit outputs the drive signal to gradually increase an ON period of each of the first transistor and the second transistor, in response to the feedback voltage exceeding the first voltage, and to gradually reduce the ON period of each of the first transistor and the second transistor, in response to the feedback voltage dropping below the second voltage.