Flyback Voltage Superposition Circuit for Overpower Protection
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Solution Overview
Problem
Existing power supply apparatuses with over power protection functions are not designed to operate smoothly across varying output voltages, leading to potential damage from excessive current when trying to trigger the protection mechanism, especially when switching between 5 volts and 20 volts.
Innovation Solution
Incorporating a voltage superposition circuit and a voltage detection circuit connected to a pulse width modulation controller, which supplies a superposition voltage to the detection circuit when the output voltage is below a predetermined level, allowing the controller to accurately trigger the over power protection function regardless of the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the output voltage is increased from 5 volts to 20 volts to increase output power, then the output power is improved, but the over power protection function cannot operate smoothly when the output voltage is 5 volts but designed for 20 volts
Solution Approach 1:
The patent implements a dynamic voltage superposition mechanism that adapts to different output voltage conditions. When the output voltage is 5V, the voltage superposition circuit adds a compensation voltage to the sensing voltage, enabling the over-power protection trigger level to reach the designed threshold. This dynamic adjustment ensures the protection function operates correctly across different voltage modes while maintaining the fixed trigger level design.
Solution Approach 2:
The patent changes the effective trigger parameter by superimposing an additional voltage on the sensing voltage through the voltage superposition circuit. This parameter modification allows the same protection circuit to achieve different effective trigger levels depending on the output voltage condition, resolving the contradiction between fixed design and variable operation requirements.
2Reliability
If the trigger level of over power protection is kept constant for 20 volts design, then the over power protection function works for 20 volts, but the output current must be greater than rated current to achieve trigger level at 5 volts, causing power components to be damaged
Solution Approach 1:
The voltage superposition circuit acts as an intermediary that modifies the sensing voltage before it reaches the comparison circuit. By adding a compensation voltage proportional to the output voltage, it enables the protection function to trigger at the correct current level for each voltage mode without requiring separate protection circuits, thus preventing component damage while maintaining reliability.
3Reliability
If separate over power protection circuits are designed for different output voltages, then each voltage mode has proper protection, but the device complexity increases
Solution Approach 1:
The patent implements a universal over-power protection circuit that functions correctly for both 5V and 20V output modes through the voltage superposition mechanism. The single protection circuit achieves multi-functionality by dynamically adjusting its effective trigger level based on the output voltage condition, eliminating the need for separate protection circuits for each voltage mode and reducing overall system complexity.
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
Ensures the over power protection function operates smoothly for both 5 volts and 20 volts, preventing power components from exceeding rated voltage or current conditions and avoiding damage, while the added circuits remain cost-effective and located at the primary side of the power supply apparatus.
Implementation Method 1
The voltage detection circuit detects a sensing voltage of the sensing resistor
Implementation Method 2
The voltage superposition circuit supplies a superposition voltage to the voltage detection circuit when an output voltage of the power supply apparatus is less than a predetermined output voltage
Implementation Method 3
The pulse width modulation controller is configured to turn off the main converter when the sensing voltage plus the superposition voltage is greater than an over power protection voltage
Implementation Method 4
The transformer comprises a primary side winding, an auxiliary winding and a secondary side winding. When the electronic apparatus informs the power supply apparatus of the required voltage, the pulse width modulation controller changes a voltage of the primary side winding, and then the secondary side winding induces the voltage of the primary side winding to generate a voltage
Data Source
AI summary
A power supply apparatus includes a main converter, a voltage superposition circuit, a voltage detection circuit and a pulse width modulation controller. The voltage superposition circuit is electrically connected to the main converter. The voltage detection circuit is electrically connected to the main converter and the voltage superposition circuit. The pulse width modulation controller is electrically connected to the main converter and the voltage detection circuit. The main converter includes a sensing resistor. The voltage detection circuit detects a sensing voltage of the sensing resistor. The voltage superposition circuit supplies a superposition voltage to the voltage detection circuit when an output voltage of the power supply apparatus is less than a predetermined output voltage, and then the voltage detection circuit sends the sensing voltage and the superposition voltage to the pulse width modulation controller.