Polarity Sensing Circuit for Low Voltage Power Efficiency
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Solution Overview
Problem
Conventional bridge rectifier circuits using diodes incur significant power losses when dealing with low dc input voltages, leading to inefficient voltage conversion in portable consumer electronics devices.
Innovation Solution
A polarity sensing circuit that replaces at least one diode in a diode bridge configuration with a transistor, allowing the decision circuit to determine the polarity of the input voltage based on the transistor's collector or emitter current, and configures a main power supply with switched transistors for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a diode bridge rectifier is used, then the circuit can automatically handle voltage polarity reversal, but significant power losses occur due to diode voltage drops
Solution Approach 1:
The patent changes the operating parameters of the rectification circuit by replacing diodes with transistors that can be actively controlled. The transistors are switched on and off based on the detected polarity, allowing the circuit to adapt its configuration dynamically. This active control enables the circuit to minimize voltage drops and power losses while maintaining the ability to handle polarity reversal, directly resolving the contradiction between adaptability and energy loss.
Solution Approach 2:
The polarity sensing circuit automatically detects the input voltage polarity and generates control signals to configure the active rectifier circuit accordingly, without requiring external intervention. The system serves itself by autonomously adapting its configuration to the input conditions, eliminating the need for manual polarity selection while optimizing power efficiency through active device control.
2Loss of energy
If active devices (transistors) are used instead of diodes, then power losses are reduced, but a separate polarity sensing circuit is required to control the switching
Solution Approach 1:
The patent combines the polarity sensing function and the active rectification function into a single integrated circuit structure. The polarity sensing circuit and the active rectifier share common components and are tightly coupled, allowing the sensing circuit to directly control the rectifier transistors. This merging reduces the overall system complexity compared to having completely separate sensing and rectification subsystems, while still achieving the power efficiency benefits of active devices.
Solution Approach 2:
The active rectifier circuit is designed to perform multiple functions: it acts as both the rectification element and the power conversion element. The same transistors that perform rectification are controlled by the polarity sensing circuit, eliminating the need for separate diode bridges and reducing the overall number of components. This multi-functionality approach reduces circuit complexity while maintaining the power efficiency advantages of active devices.
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 significantly reduces power losses and enhances voltage efficiency by automatically configuring the rectification circuit to handle the input voltage correctly, providing a more efficient power supply for portable devices.
Implementation Method 1
the transistor is carrying current through its base-emitter or base-collector p-n junction
Data Source
AI summary
A dc input circuit receives a dc input voltage. At least four rectification elements are coupled to each other in a diode bridge configuration, where an input of the diode bridge configuration is coupled to the dc input circuit to receive the dc input voltage. At least one of the rectification elements includes a transistor. A decision circuit indicates, as a function of one of collector current and emitter current of the transistor, that the received dc input voltage has normal or reversed polarity. Other embodiments are also described and claimed.