Synchronous Push-Pull Converter for Adjustable Transfer Ratios
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Solution Overview
Problem
Existing push-pull converters with diode rectification are limited to a transfer ratio of one, leading to increased power consumption and board area requirements, especially when higher transfer ratios are needed, and they require significant board space due to the use of multiple rectifying elements.
Innovation Solution
A push-pull converter design utilizing a transformer with opposite polarity windings, switch transistors, and rectification transistors that operate synchronously, allowing for adjustable transfer ratios and reduced power consumption by minimizing dead time and using fewer transistors, thus reducing board space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a full-bridge converter is used to achieve transfer ratios greater than one, then the transfer ratio capability is improved, but the board area requirement increases due to requiring double the rectifying elements
Solution Approach 1:
The rectification transistors are configured to perform multiple functions: they act as switching elements during the forward conduction phase and as rectification elements during the reverse conduction phase. This multi-functionality eliminates the need for separate rectifying elements, reducing board area while maintaining full-bridge converter capabilities for transfer ratios greater than one
Solution Approach 2:
The patent merges the switching and rectification functions into a single set of transistors. The same transistors that switch the primary side also perform rectification on the secondary side through synchronous operation, combining what would traditionally require separate component sets into one integrated system
2Device complexity
If diode rectification is used in a push-pull converter, then the device complexity is reduced, but the transfer ratio is limited to one and power consumption increases
Solution Approach 1:
The patent employs dynamic control of rectification transistors that can be synchronously operated with the switching transistors. This dynamic operation allows the converter to adapt to different transfer ratio requirements by adjusting the duty cycle and timing, unlike static diode rectification which is limited to fixed operation modes
Solution Approach 2:
By changing the operational parameters of the rectification transistors (gate timing, duty cycle, conduction angle), the converter can achieve variable transfer ratios. The parameter control of active transistors provides flexibility that passive diodes cannot offer, enabling transfer ratios greater than one while maintaining relatively simple circuit topology
3Loss of energy
If synchronous operation of switch and rectification transistors is implemented, then power consumption is reduced through minimized dead time, but the control complexity increases
Solution Approach 1:
The control system uses feedback from the switching transistor operation to automatically generate the gate signals for rectification transistors. By monitoring the switching cycle and using this information to drive the rectification transistor gates, the system achieves synchronous operation that minimizes dead time and power loss without requiring complex external control circuitry
Solution Approach 2:
The rectification transistors are controlled to self-synchronize with the switching transistors through shared control signals and circuit topology. The control mechanism leverages the existing switching waveforms and transformer feedback to automatically coordinate the rectification phase, reducing the need for additional complex control logic while achieving minimal dead time operation
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
The solution achieves reduced power consumption and board space usage while enabling adjustable transfer ratios, improving efficiency and reducing power dissipation in high-frequency applications by synchronously operating switch and rectification transistors and using fewer transistors compared to traditional full-bridge designs.
Implementation Method 1
a transformer comprising a first set of transformer windings and a second set of transformer windings
Data Source
Figure 1~3
Figure 2
Figure 4a
AI summary
A push-pull converter (400) configured to convert an input voltage to an output voltage according to a transfer ratio is provided. The push-pull converter (400) comprises a transformer (410), a first and a second switch transistor (421, 422) arranged to operatively provide the input voltage to the transformer (410) such that the transfer ratio is obtainable, a first and a second rectification transistor (431, 432) arranged to operatively receive a first and a second part, respectively, of the output voltage from the transformer (410) such that the transfer ratio is obtainable. The push-pull converter (400) is further configured to synchronously operate the first switch transistor (421) and the first rectification transistor (431), synchronously operate the second switch transistor (422) and the second rectification transistor (432), and operate the first and second switch transistors (421, 422) 180 degrees out of phase with respect to each other.