Switching Power Supply Voltage Mode Transition Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Switching power supplies employing active clamp systems with flyback transformers face issues of overshoot, undershoot, and through-current when output voltage is abruptly changed, leading to instability and potential malfunction.
Innovation Solution
A power supply apparatus with a transformer, first and second switching elements, a capacitor, and a control unit that gradually adjusts the turn-on duty of the switching elements based on feedback signals to maintain predetermined voltage states, preventing abrupt changes and through-currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the output voltage of the switching power supply is changed abruptly to improve responsiveness, then the responsiveness is improved, but overshoot and undershoot occur and through-current flows through the switching element
Solution Approach 1:
The control unit performs preliminary action by detecting the desired voltage state before actual switching occurs, and prepares the switching element duty cycle in advance. When voltage state switching is detected, the control unit gradually adjusts the turn-on duty of the switching element from the old duty cycle to the new duty cycle over a predetermined period, preventing abrupt changes that cause overshoot, undershoot, and through-current.
Solution Approach 2:
The control unit dynamically adjusts the turn-on duty of the switching element based on the detected voltage state and elapsed time. The duty cycle transitions smoothly from the old value to the new value according to a predetermined time profile, allowing the system to adapt responsively while maintaining stability during the transition period.
2Speed
If the output voltage of the switching power supply is changed abruptly to improve responsiveness, then the responsiveness is improved, but a through-current flows through the switching element
Solution Approach 1:
The control unit performs preliminary action by detecting the desired voltage state before actual switching occurs, and prepares the switching element duty cycle in advance. When voltage state switching is detected, the control unit gradually adjusts the turn-on duty of the switching element from the old duty cycle to the new duty cycle over a predetermined period, preventing abrupt changes that cause overshoot, undershoot, and through-current.
Solution Approach 2:
The control unit dynamically adjusts the turn-on duty of the switching element based on the detected voltage state and elapsed time. The duty cycle transitions smoothly from the old value to the new value according to a predetermined time profile, allowing the system to adapt responsively while maintaining stability during the transition period.
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
Prevents overshoot and undershoot, reduces through-currents, and enhances the reliability of the switching power supply by stabilizing the output voltage through controlled switching operations.
Implementation Method 1
a transformer including a primary winding and a secondary winding
Implementation Method 2
a capacitor connected in series to the second switching element, and is connected in parallel to the primary winding of the transformer together with the second switching element
Data Source
AI summary
The power supply apparatus includes a control unit configured to perform control of gradually changing a turn-on duty of a first switching element when a first voltage mode is switched to a second voltage mode or when the second voltage mode is switched to the first voltage mode.