Integrated Offline Power Supply for Compact Low-Voltage Applications
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Solution Overview
Problem
Existing low-voltage power supplies for low-power devices in home automation and energy efficiency applications are bulky, expensive, and inefficient due to the need for large high-voltage input and output capacitors, as well as additional components, which occupy valuable space and increase costs.
Innovation Solution
A power supply system that integrates a rectifier, switch, inductor, and control circuitry within a single chip, using a high-speed switch to generate DC power levels by selectively coupling rectified AC power to an inductor and capacitor, and transitioning to a standby mode when energy storage is insufficient, reducing component size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large high-voltage input and output capacitors are used in existing low-voltage power supplies, then the power supply can maintain stable voltage levels, but the device size and cost increase significantly
Solution Approach 1:
The patent changes the operating parameters by using a high-speed switch (5-20 MHz) to generate voltage pulses that charge the capacitor, allowing the system to maintain stable voltage with a much smaller capacitor value (1 nF to 10 μF) compared to conventional designs. This parameter change in switching frequency enables reduced component size while maintaining voltage stability.
Solution Approach 2:
The system employs periodic voltage pulses generated by the high-speed switch to charge the output capacitor. This periodic action allows the capacitor to be recharged rapidly in short intervals, enabling the use of smaller capacitance values while maintaining continuous stable output voltage, thus reducing device volume.
2Loss of energy
If additional components are included in the power supply circuit, then the power conversion efficiency improves, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges multiple functions into a single integrated chip that includes the rectifier, high-speed switch, inductor, and control circuitry. This consolidation maintains the power conversion efficiency of complex circuits while reducing the actual number of discrete components, thereby lowering device complexity and manufacturing cost.
Solution Approach 2:
The integrated chip performs multiple functions simultaneously: rectification, high-frequency switching, inductance, and control. This multi-functionality allows the system to achieve efficient power conversion without requiring separate discrete components for each function, reducing overall device complexity.
3Productivity
If the processor operates continuously in active mode, then all tasks can be executed without interruption, but the power consumption increases and battery life decreases
Solution Approach 1:
The system dynamically transitions the processor between active and standby modes based on the charging cycle phase. During the zero-crossing window when the AC voltage passes through zero, the processor enters standby mode to conserve energy. This dynamic state change allows the system to balance productivity with energy efficiency, extending battery life while maintaining task execution capability.
Solution Approach 2:
The system performs preliminary charging of the capacitor during active periods before transitioning to standby mode. This preliminary action ensures that sufficient energy is stored in the capacitor to maintain processor operation during the zero-crossing window, allowing the processor to safely enter standby without interrupting task execution.
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 provides a compact, cost-effective low-voltage power supply that eliminates the need for input capacitors and reduces the size of other components, preventing processor task interruptions by managing power levels through active and standby modes, ensuring reliable operation.
Implementation Method 1
a rectifier having an input coupled to the input line and an output
Implementation Method 2
a switch having a first end coupled to the output of the rectifier and a second end selectively coupled to an inductor
Implementation Method 3
a capacitor coupled to the inductor
Data Source
AI summary
According to one aspect, embodiments of the invention provide a power supply system comprising an input line configured to receive input AC power, a rectifier having an input coupled to the input line and an output, a switch having a first end coupled to the output of the rectifier and a second end selectively coupled to an inductor, a capacitor coupled to the inductor, and control circuitry coupled to the inductor and the capacitor, wherein the control circuitry is configured to control the switch to selectively couple the output of the rectifier to the inductor to generate a first DC power level, operate in a first mode of operation while receiving the first DC power level, detect a phase angle of the rectified AC power, and transition into a second mode of operation in response to detection of the phase angle.