DC/DC Converter Burst Mode Frequency Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flyback DC/DC converters experience increased switching losses and potential audible ringing due to excessively high burst frequencies in light load states, degrading efficiency and causing noise.
Innovation Solution
A burst mode adjustment circuit is introduced to dynamically adjust the voltage at the current detection terminal based on the electrical state of the DC/DC converter, allowing for control over the transition to and from burst mode, thereby modifying the burst frequency to optimize operation conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the DC/DC converter operates in burst mode to reduce power consumption in light load states, then power consumption is reduced, but switching losses increase and audible ringing occurs due to excessively high burst frequencies
Solution Approach 1:
The patent applies dynamics by making the current detection terminal voltage dynamically adjustable based on the electrical state of the DC/DC converter. The burst mode adjustment circuit modifies the voltage at the current detection terminal according to load conditions and input voltage, enabling the burst frequency to be optimized in real-time. This dynamic adjustment resolves the contradiction by allowing the system to operate in burst mode for power savings while preventing excessively high frequencies that cause switching losses and audible ringing.
Solution Approach 2:
The patent employs parameter changes by altering the voltage at the current detection terminal to control the transition threshold between normal mode and burst mode. By changing this voltage parameter based on electrical state (load current and input voltage), the system optimizes burst frequency to reduce power consumption without incurring excessive switching losses or audible noise.
2Use of energy by moving object
If the DC/DC converter operates in burst mode with high switching frequency, then power consumption is reduced, but audible noise is generated
Solution Approach 1:
The system dynamically adjusts the current detection terminal voltage based on electrical state to control burst frequency. This dynamic control ensures that burst mode operation reduces power consumption while keeping the switching frequency below the audible range, thereby eliminating audible noise while maintaining energy efficiency.
Solution Approach 2:
The patent implements feedback by monitoring the electrical state of the DC/DC converter and using this information to adjust the current detection terminal voltage. This feedback mechanism ensures that burst mode operation maintains optimal frequency characteristics, reducing power consumption without generating audible noise.
3Loss of energy
If the voltage at the current detection terminal is increased to prevent burst mode transition, then switching losses are reduced, but power consumption increases in light load states
Solution Approach 1:
The patent resolves this contradiction by making the current detection terminal voltage dynamic rather than fixed. The voltage is adjusted based on electrical state: in heavy load conditions, the voltage is set higher to prevent premature burst mode transition and reduce switching losses; in light load conditions, the voltage is adjusted to enable burst mode operation and reduce power consumption. This dynamic approach optimizes both switching losses and power consumption across different operating conditions.
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 solution effectively reduces switching losses and prevents burst frequencies from entering the audible range, enhancing efficiency and reducing noise by dynamically adjusting the burst mode operation based on load and input conditions.
Implementation Method 1
a photocoupler having a light-emitting element and a light-receiving element; a feedback circuit structured to drive the light-emitting element of the photocoupler
Data Source
AI summary
A primary-side controller comprises a feedback (FB) terminal coupled to a light-receiving element of a photocoupler so as to receive a feedback signal from the photocoupler, and a current detection (CS) terminal that receives a current detection signal that corresponds to a voltage drop across a sense resistor RS. The primary-side controller includes a current mode modulator that generates a control pulse based on the voltage at the FB terminal and the voltage at the CS terminal. The primary-side controller is configured to be switchable between a normal mode and a burst mode. When the electrical state of the DC/DC converter satisfies a predetermined condition, a burst mode adjustment circuit inhibits transition to the burst mode, or otherwise forces transition from the burst mode to the normal mode.