Switching Power Supply Peak Current Adjustment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional switching power supply apparatuses face challenges in adjusting peak current values during intermittent oscillation periods, leading to variations in overcurrent protection levels due to production tolerance and temperature characteristics, affecting power supply efficiency and stability.
Innovation Solution
A semiconductor device with a turn-on control circuit, feedback control circuit, current detecting terminal, offset current generating circuit, and turn-off control circuit is used to adjust the peak current value of the switching element, incorporating an offset adjusting resistor to minimize variations in overcurrent protection levels by varying the offset current based on feedback signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If intermittent oscillation control is used under light load to improve power efficiency, then power supply efficiency is improved, but the oscillation frequency drops to audio-frequency range causing noise and output ripple
Solution Approach 1:
The patent applies dynamics by making the oscillation frequency variable rather than fixed. The control circuit dynamically adjusts the oscillation frequency based on the load condition, maintaining high frequency even during intermittent oscillation under light load. This resolves the contradiction by enabling the system to achieve power efficiency improvement through intermittent oscillation while preventing the frequency drop that causes noise and output ripple.
2Object-generated harmful factors
If peak current value is lowered during intermittent oscillation to reduce noise, then noise is reduced, but the number of switching times increases making power efficiency improvement ineffective
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the peak current threshold based on the oscillation phase and load conditions. Instead of using a fixed low peak current value that increases switching frequency, the control circuit modifies the peak current parameter adaptively. This allows the system to maintain appropriate switching times for power efficiency while controlling noise through intelligent parameter modulation rather than simple reduction.
3Ease of operation
If offset adjusting resistor is used to adjust peak current value during intermittent oscillation, then peak current adjustment is achieved, but overcurrent protection level varies due to production tolerance and temperature characteristics
Solution Approach 1:
The patent applies feedback by implementing a control circuit that continuously monitors the actual peak current and overcurrent protection levels, then adjusts the offset dynamically to compensate for variations. Instead of relying on a fixed resistor value that is subject to production tolerance and temperature drift, the feedback mechanism actively corrects deviations in real-time. This resolves the contradiction by maintaining consistent overcurrent protection levels while still allowing peak current adjustment during intermittent oscillation.
Data Source
AI summary
A switching power supply apparatus includes: a turn-on control circuit which generates a turn-on signal; a feedback control circuit which generates a reference voltage VEAO indicating a limitation level for a current ID flowing into a switching element, by referring to a feedback signal IFB indicating an output current voltage VOUT, the limitation level which decreases as the output direct current voltage becomes greater; an overcurrent protection level setting circuit which generates a reference voltage VLR indicating an overcurrent protection level; a current detecting terminal; an offset current generating circuit which provides an offset current IIS from the current detecting terminal, the offset current IIS which is greater as the output current voltage VOUT is greater; and a turn-off control circuit which generates a turn-off signal by comparing a voltage applied to the current detecting terminal with each of the reference voltage VEAO, and the reference voltage VLR.