Switching Power Supply Intermittent Oscillation Control
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Solution Overview
Problem
Existing primary-side regulated switching power-supply devices face challenges in detecting output voltage variations during intermittent oscillation operations, especially at low loads, leading to compromised dynamic characteristics and standby performance.
Innovation Solution
A switching power-supply device with a transformer, switching device, oscillation circuit, output voltage generating circuit, control-circuit power-supply voltage generating circuit, and feedback control circuit, including a COMP-voltage comparator and intermittent-oscillation control circuit that transitions between first and second intermittent oscillation operations based on voltage thresholds to maintain dynamic and standby performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the oscillation cycle of the intermittent oscillation operation is lengthened to reduce switching loss during no load or light load, then standby characteristic is improved, but dynamic characteristic is sacrificed because output voltage changes cannot be detected until the next switching operation
Solution Approach 1:
The patent applies dynamics by making the oscillation cycle variable rather than fixed. The intermittent oscillation control circuit dynamically adjusts the oscillation cycle between a first cycle (shorter period) and a second cycle (longer period) based on the COMP voltage level. This allows the system to adapt its switching behavior to current load conditions, achieving both low standby power consumption and good dynamic response when needed.
Solution Approach 2:
The patent changes the parameter of oscillation cycle duration based on system state. When the COMP voltage is low (indicating sufficient output voltage), the system uses the second intermittent oscillation operation with the longer cycle to reduce switching loss. When the COMP voltage exceeds a threshold (indicating output voltage droop), the system switches to the first intermittent oscillation operation with the shorter cycle to improve dynamic response and detect voltage changes promptly.
2Reliability
If the oscillation cycle is shortened to improve dynamic characteristic and detect output voltage changes promptly, then responsiveness to load changes is improved, but switching loss increases and standby characteristic deteriorates
Solution Approach 1:
The system dynamically selects between two oscillation cycle modes based on real-time voltage conditions. The intermittent oscillation control circuit monitors the COMP voltage and automatically transitions between the first intermittent oscillation operation (shorter cycle for dynamic response) and the second intermittent oscillation operation (longer cycle for energy efficiency), ensuring optimal performance under varying load conditions.
Solution Approach 2:
The oscillation cycle parameter is changed based on the COMP voltage threshold. When voltage droop is detected (COMP voltage > threshold), the system switches to the shorter first cycle to improve dynamic characteristic. When voltage is stable (COMP voltage < threshold), the system uses the longer second cycle to reduce switching loss, thus adapting the parameter to current operational needs.
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 allows for excellent standby characteristics without sacrificing dynamic characteristics by using different intermittent oscillation cycles for varying load conditions, reducing switching loss and improving responsiveness to load changes.
Implementation Method 1
a transformer that includes a primary winding, a secondary winding, and an auxiliary winding
Data Source
AI summary
A switching power-supply device includes a COMP-voltage comparator circuit that compares a COMP-voltage obtained by performing phase compensation on the feedback signal, with a first threshold voltage which is a threshold value; and an intermittent-oscillation control circuit that, if it is detected by the COMP-voltage comparator circuit that the COMP-voltage is lower than the first threshold voltage, stops the switching operation of the switching device and performs a transition to a first intermittent oscillation operation in which the switching device performs the switching operation every predetermined first period, wherein if a predetermined delay period elapses in a state where the COMP-voltage is lower than the first threshold voltage, the intermittent-oscillation control circuit performs a transition to a second intermittent oscillation operation in which the switching device performs the switching operation every second period which is an integral multiple of the first period.