Power Supply Unit Light-Load Power Reduction via Burst Mode Control
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Solution Overview
Problem
Conventional power supply units continue to consume significant power at no-load or light-load conditions due to operational internal circuitry, leading to high energy wastage over time, and require costly components with stability issues.
Innovation Solution
A power supply unit incorporating a switching power converter, load detector, voltage detector, and disable circuit that dynamically adjusts the operation of the power switch based on load conditions and output voltage, entering an energy-saving state when load is low, thereby reducing power consumption and eliminating the need for costly components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply unit operates continuously to maintain output voltage, then the output voltage stability is improved, but the power consumption increases significantly at light-load or no-load conditions
Solution Approach 1:
The power supply unit employs burst mode operation where the power switch operates in periodic cycles - switching on for a predetermined time period to recharge the output capacitor, then turning off to reduce power consumption. This periodic action maintains output voltage stability while significantly reducing power consumption during light-load or no-load conditions.
Solution Approach 2:
The system dynamically adjusts its operation based on load conditions. The controller monitors the output voltage and load current, and automatically transitions between continuous conduction mode and burst mode. This dynamic adaptation allows the power supply to optimize between voltage stability and power consumption based on real-time operating conditions.
2Use of energy by moving object
If a photocoupler with higher current transfer ratio is used to reduce forward bias current, then the power consumption of feedback network is reduced, but the component cost increases and stability issues arise
Solution Approach 1:
The invention introduces an intermediary current source circuit that actively compensates for the photocoupler's forward bias current. This current source is controlled by the controller to provide the exact current needed to maintain photocoupler operation in the linear region, eliminating stability issues while allowing the use of standard photocouplers with moderate current transfer ratios.
Solution Approach 2:
The system dynamically adjusts the forward bias current parameter of the photocoupler based on operating conditions. The controller monitors the feedback signal and adjusts the current source output to maintain optimal photocoupler operation, ensuring stability across varying load conditions while minimizing power consumption.
3Manufacturing precision
If the power switch operates continuously to maintain output voltage, then the voltage regulation is improved, but the energy wastage increases over time
Solution Approach 1:
The power supply uses periodic burst mode operation where the power switch turns on for predetermined time intervals to recharge the output capacitor, then remains off to conserve energy. This periodic action maintains voltage regulation precision by ensuring the output capacitor is periodically recharged to the target voltage level while minimizing energy wastage during off periods.
Solution Approach 2:
The system employs feedback control where the controller monitors the output voltage level and uses this information to determine when to activate the power switch. The feedback mechanism ensures that the power switch operates only when necessary to maintain voltage regulation, preventing unnecessary energy wastage while preserving voltage precision through intelligent control.
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
The solution effectively reduces power consumption during no-load and light-load conditions, enhances stability, and lowers component costs, making the power supply unit more competitive and efficient.
Implementation Method 1
a switching power converter responsive to a control signal to switch a power switch thereof to provide an output voltage and an output current
Implementation Method 2
a load detector to detect a load condition to generate a first signal
Implementation Method 3
a voltage detector to compare the output voltage with a reference voltage to generate a second signal
Data Source
AI summary
A power supply unit includes a switching power converter responsive to a control signal to switch a power switch thereof to provide an output voltage and an output current for a load. To reduce light-load or no-load power consumption of the power supply unit, the power supply unit repeats a process of stopping switching the power switch and recovering switching the power switch for a period of time once the output voltage decreases to be lower than a reference voltage.