Isolated Switch-Mode Power Supply Standby Power Reduction
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Solution Overview
Problem
Existing isolated switch-mode power supply devices face challenges in reducing power consumption during the standby mode due to continued power loss in control circuits and elements, even when switching is paused, and existing methods fail to sufficiently minimize power consumption while maintaining stable voltage control.
Innovation Solution
The proposed isolated switch-mode power supply device incorporates a control power supply source, first and second control units, and a control power supply switch to manage the switching element's operation in continuous and burst modes, allowing for the selective disconnection of control power during pause periods, using a capacitance element unit and discharge means to maintain voltage stability and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control power is continued to be supplied to control circuits and elements during the switching pause period in standby mode, then the circuits and elements remain operational and ready to respond, but power loss occurs in these circuits and elements during the pause period
Solution Approach 1:
The patent applies preliminary action by storing control power in a capacitor before the switching pause period begins. The capacitor is charged during the switching operation period and then supplies power to the control circuits during the pause period, ensuring they remain operational without continuous external power supply. This preparatory charging action enables the circuits to function autonomously during the pause period.
Solution Approach 2:
The patent implements periodic action by alternating between switching operation periods and switching pause periods. During operation periods, the control circuits are actively powered and control switching elements. During pause periods, the circuits switch to capacitor-powered mode with reduced or zero power consumption from the main power supply. This periodic switching between active and standby states reduces average power loss while maintaining periodic readiness.
2Loss of energy
If the switching of the switching element is stopped during the switching pause period, then the switching loss per unit time is reduced, but the outputted voltage decreases over time
Solution Approach 1:
The patent uses a capacitor as an intermediary energy storage element between the power input and the output. The capacitor accumulates energy during switching operation periods and then releases this stored energy during switching pause periods to maintain the output voltage. This intermediary capacitor decouples the direct relationship between switching activity and output voltage, allowing voltage maintenance even when switching is paused.
Solution Approach 2:
The patent changes the operational parameters of the power supply system by transitioning from continuous switching to periodic burst-mode switching. During pause periods, the switching frequency is reduced to zero, and the system relies on the capacitor's stored energy to maintain output parameters. This parameter change from continuous to intermittent operation reduces switching losses while the capacitor compensates for the temporary reduction in power conversion activity.
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 power consumption by stopping control power supply during pause periods without affecting voltage stability, allowing for efficient switching resumption and minimizing overall power usage in the standby mode.
Implementation Method 1
a capacitor configured to supply control power required for controlling the switching
Implementation Method 2
discharge means configured to decrease the capacitor charge voltage when the outputted voltage becomes equal to or lower than a lower limit voltage
Data Source
Figure 1
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AI summary
The present invention provides an isolated switch-mode power supply device capable of sufficiently reducing power consumption in a standby mode. An isolated switch-mode power supply device 1 includes: a capacitor C5 that supplies control power required for controlling switching of a switching element Q1; a first control unit 10 that includes a constant current supplying unit 14 for supplying a constant current and that controls the switching of the switching element Q1; a switching element Q11 that connects or disconnects the first control unit 10 and the capacitor C5; a capacitance element unit 121 having a capacitor C4 to which a constant current is supplied from the constant current supplying unit 14, a capacitor charge voltage of the capacitance element unit 121 changing according to an outputted voltage in the standby mode; and a second control unit 12 that controls power supply to the first control unit 10 by closing or opening the switching element Q11 during a switching pause period in the standby mode according to the capacitor charge voltage of the capacitor C4.