Integrated Rectifier IC for Insulated Power Supply Efficiency
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Solution Overview
Problem
Conventional insulation type switching power supplies face inefficiencies due to the use of diodes with large forward drop voltage and require complex matching processes between rectifier transistors and controller ICs, leading to increased circuit area and cost.
Innovation Solution
A rectifier IC is developed that integrates a transistor chip and a controller chip in a single package, allowing for ON/OFF control of the transistor based on node voltage detection, enhancing conversion efficiency and simplifying the selection process by eliminating the need for user-adjusted gate resistance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a diode with large forward drop voltage is used as secondary side rectifier means, then the circuit structure is simple, but the conversion efficiency is low
Solution Approach 1:
The patent merges the rectifier transistor and controller IC into a single integrated package, creating a rectifier IC that functions as complete secondary side rectifier means. This integration maintains circuit simplicity while achieving low on-resistance rectification to improve conversion efficiency, resolving the contradiction between simple structure and high efficiency.
2Loss of energy
If a rectifier transistor with small on-resistance is used instead of diode, then the conversion efficiency is improved, but the device complexity and cost increase due to additional components
Solution Approach 1:
The rectifier transistor and controller IC are merged into a single integrated package, reducing the number of discrete components while maintaining the low on-resistance advantage. This integration eliminates the need for external matching components and reduces circuit complexity.
Solution Approach 2:
The integrated rectifier IC serves multiple functions: rectification, control, and protection, all within a single device. The controller IC inside the package provides universal control capabilities that work with the rectifier transistor, eliminating the need for separate matching components.
3Loss of energy
If a rectifier transistor and separate controller IC are used, then the conversion efficiency is improved, but the ease of operation deteriorates due to required matching work
Solution Approach 1:
By integrating the controller IC and rectifier transistor in a single package with predetermined internal connections, the patent eliminates the need for user-performed matching work. The internal gate resistance and other matching parameters are factory-set, improving ease of operation while maintaining high conversion efficiency.
Solution Approach 2:
The matching parameters such as gate resistance are predetermined and set during manufacturing before the product reaches the user. This preliminary action eliminates the need for field adjustment or matching work, making the device easier to operate while maintaining optimal efficiency.
Data Source
AI summary
A rectifier IC includes, in a single package, a transistor chip in which a transistor is integrated, a controller chip that detects a drain voltage (VD) and a source voltage (VS) of the transistor so as to perform ON/OFF control of the transistor, and functions as secondary side rectifier means of an insulation type switching power supply. The controller chip turns on the transistor when VD is lower than VS and turns off the transistor when VD is higher than VS. The insulation type switching power supply includes a transformer supplied with an input voltage, a control unit that controls primary side current of the transformer according to a feedback signal, a rectifying and a smoothing unit that rectifies and smooths a secondary side voltage of the transformer so as to generate an output voltage, and an output feedback unit that generates the feedback signal according to the output voltage.