Insulation-Type Synchronous DC/DC Converter Idle Current Reduction
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Solution Overview
Problem
Conventional DC/DC converters have inefficiencies due to the requirement of a shunt regulator, which consumes significant idle current, reducing the overall efficiency of the AC/DC converter.
Innovation Solution
A synchronous rectifier controller is introduced, which includes a driver circuit and an error amplifier to control the synchronous rectifier transistor, reducing current consumption by integrating these components on a single module and isolating power and ground planes, thereby replacing the conventional shunt regulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a shunt regulator is used to maintain stable output voltage, then voltage stability is improved, but idle current consumption increases significantly
Solution Approach 1:
The patent extracts the error amplifier function from the conventional shunt regulator configuration and implements it as a separate synchronous rectifier controller on the secondary side. This separation allows the error amplifier to operate with much lower current consumption while maintaining voltage stability through the photo coupler feedback mechanism.
Solution Approach 2:
The patent introduces a photo coupler as an intermediary device to transmit feedback signals between the primary and secondary sides. This optical isolation enables the error amplifier to control the switching transistor indirectly through the photo coupler, eliminating the need for high idle current while maintaining stable output voltage.
2Use of energy by moving object
If a synchronous rectifier controller with error amplifier is used, then current consumption is reduced, but device complexity increases
Solution Approach 1:
The patent merges the driver circuit and error amplifier into a single synchronous rectifier controller integrated circuit on the secondary side. This integration reduces the number of discrete components and simplifies the overall system architecture while maintaining low current consumption through optimized internal design.
Solution Approach 2:
The synchronous rectifier controller performs multiple functions including error amplification, pulse generation for the switching transistor, and feedback control through the photo coupler. This multi-functionality consolidates what would traditionally require separate components into a single device, reducing complexity while achieving low current consumption.
3Object-affected harmful factors
If power supply planes are isolated for the error amplifier and driver circuit, then electromagnetic interference is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent segments the power supply system into separate power supply planes for the error amplifier and driver circuit within the synchronous rectifier controller. This segmentation isolates sensitive analog circuits from switching noise, reducing electromagnetic interference while the integrated design keeps PCB layout requirements manageable.
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 configuration significantly reduces current consumption and improves efficiency, especially in light load states, by lowering power consumption and switching frequency, thus enhancing the performance of the DC/DC converter.
Implementation Method 1
a primary controller coupled to an output of the photo coupler, and configured to control the switching transistor according to a feedback signal from the photo coupler
Implementation Method 2
a transformer having its primary winding and its secondary winding
Data Source
AI summary
A synchronous rectifier controller is provided on a secondary side of an insulation-type synchronous DC/DC converter and controls the synchronous rectifier transistor. A driver circuit controls the synchronous rectifier transistor. A photo coupler connection terminal is coupled to an input side of the photo coupler. An error amplifier amplifies an error between a voltage detection signal according to an output voltage of the DC/DC converter and its target voltage, and to draw a current according to the error from an input side of the photo coupler via the photo coupler connection terminal.