Galvanically Isolated DC-DC Converter With Single Transformer Data Communication
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Solution Overview
Problem
Existing galvanically isolated DC-DC converters require multiple isolation transformers for power, feedback control, and data channels, leading to increased complexity, size, and cost, while also suffering from poor common mode transient rejection and efficiency degradation due to high galvanic isolation ratings.
Innovation Solution
A DC-DC converter circuit utilizing a single isolation transformer with magnetic coupling for power and data transmission, incorporating a common mode transient rejection circuit and multiplexing data channels with power control signals to reduce the number of isolated links, thereby simplifying the architecture and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple isolation transformers are used for power, feedback control, and data channels, then galvanic isolation reliability is improved, but device complexity and size increase
Solution Approach 1:
The patent combines multiple isolation functions (power transmission, feedback control, and data communication) into a single isolation transformer. The transformer's primary winding receives a composite signal containing power, control, and data information, while the secondary winding provides galvanically isolated output for all three functions, thereby reducing the number of transformers from three to one while maintaining isolation reliability
Solution Approach 2:
The single isolation transformer is designed to perform multiple functions simultaneously: it provides galvanic isolation for power transmission, carries feedback control signals for output regulation, and transmits data channels. This multi-functional approach eliminates the need for dedicated separate transformers for each function, reducing overall device complexity
2Reliability
If multiple isolation transformers are used, then channel isolation is improved, but manufacturing cost increases
Solution Approach 1:
By merging multiple isolation functions into a single transformer, the patent reduces the total number of components that need to be manufactured and assembled. This consolidation directly reduces manufacturing cost while maintaining channel isolation through the transformer's inherent galvanic isolation capability
3Reliability
If high galvanic isolation ratings are used, then safety is improved, but efficiency deteriorates due to energy loss
Solution Approach 1:
The patent incorporates feedback control signals transmitted through the isolated channel to monitor and regulate the output power. This feedback mechanism enables real-time adjustment of the power transmission to maintain high efficiency while preserving the high galvanic isolation rating for safety
Solution Approach 2:
The patent employs amplitude modulation of the power signal and uses comparison circuitry to generate error signals that adjust transmission parameters. By dynamically changing transmission parameters based on load conditions, the system maintains high efficiency while preserving the high galvanic isolation rating
4Reliability
If multiple dedicated isolated links are used for power control and data, then communication reliability is improved, but the number of isolated links increases
Solution Approach 1:
The patent merges power control signals and data communication into a single isolated transmission channel through the isolation transformer. Multiplexing techniques are used to combine these signals, reducing the number of isolated links from multiple dedicated channels to one unified channel while maintaining communication reliability through error detection and correction mechanisms
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 reduces the number of isolated links, minimizing size and cost while maintaining high efficiency and effective common mode transient rejection, enabling efficient power and data transmission with improved regulation capabilities.
Implementation Method 1
a single isolation transformer having a primary winding and a secondary winding magnetically coupled to the primary winding
Implementation Method 2
a transmitter connected to the secondary winding of the single isolation transformer to apply an amplitude modulation to the power signal at the secondary winding
Data Source
AI summary
A DC-DC converter includes: an transformer having a primary winding and a secondary winding magnetically coupled to the primary winding; a power oscillator applying an oscillating signal to the primary to transmit a power signal to the secondary winding; a rectifier connected to the secondary winding of the transformer to obtain an output DC voltage by rectification of the power signal; comparison circuitry to generate an error signal representing a difference between the output DC voltage and a reference voltage; a transmitter connected to the secondary winding of the transformer to apply an amplitude modulation to the power signal at the secondary winding of the transformer in response to the error signal to thereby produce an amplitude modulated signal at the primary winding; and a receiver and control circuit connected to the primary winding to control an amplitude of the oscillating signal as a function of the amplitude modulated signal.