Pulse Transformer Driver Using Alternating Polarity to Prevent Core Saturation
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Solution Overview
Problem
Traditional pulse transformers used in power supplies face challenges such as magnetic core saturation and increased response time due to large core sizes and the need for capacitors to filter DC bias, which hinder miniaturization and rapid load changes.
Innovation Solution
A driving method and device utilizing a small magnetic core pulse transformer with a multi-state driver that allows core light saturation without large drive currents, using high impedance states to optimize coupling and reduce parasitic effects, and maintaining the secondary side in a low impedance state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the average voltage of the square wave signal is applied to the pulse transformer for a long time, then the magnetic core becomes saturated and short-circuits the primary winding, but reducing the time causes insufficient charging of the control device
Solution Approach 1:
The patent applies periodic action by using alternating positive and negative voltage pulses to the primary winding. The positive pulse charges the control device while the negative pulse discharges it, creating a periodic charge-discharge cycle that prevents DC bias accumulation and magnetic core saturation while ensuring adequate charging time during each positive pulse phase.
Solution Approach 2:
The patent changes the voltage parameter by switching between positive and negative polarity pulses. This parameter change allows the system to achieve both charging (during positive pulse) and discharging (during negative pulse) of the control device, preventing magnetic core saturation while maintaining sufficient charging duration through optimized pulse width control.
2Reliability
If a capacitor is connected in series with the primary winding to filter DC bias, then magnetic core saturation is avoided, but the response time increases during load changes
Solution Approach 1:
The patent replaces the passive capacitor-based DC blocking mechanism with an active electronic switching system that generates alternating positive and negative voltage pulses. This substitution eliminates the need for series capacitors, thereby removing the RC time constant limitation and achieving fast response during load changes while still preventing magnetic core saturation through the alternating polarity approach.
Solution Approach 2:
By implementing periodic charge-discharge cycles through alternating voltage pulses, the system achieves DC bias elimination without requiring series capacitors. The periodic nature of the pulses ensures that no net DC voltage accumulates across the magnetic core, avoiding saturation while maintaining fast transient response capability.
3Reliability
If a large magnetic core is used to prevent saturation, then reliability is improved, but miniaturization is hindered
Solution Approach 1:
The patent changes the operating parameters by using alternating positive and negative voltage pulses instead of unidirectional voltage application. This parameter change allows the use of smaller magnetic cores because the alternating polarity prevents DC bias accumulation and saturation, enabling miniaturization while maintaining reliability through optimized pulse amplitude and duration control.
4Stability of the object's composition
If the control device is continuously connected to the secondary winding, then charging is maintained, but discharge path is blocked and response time increases
Solution Approach 1:
The patent implements periodic connection and disconnection of the control device to the secondary winding through alternating voltage pulses. During positive pulses, the control device is connected for charging; during negative pulses, it is disconnected or provided with a discharge path. This periodic action ensures both adequate charging and rapid discharge capability, improving response time during load changes while maintaining stable 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
This approach enables a smaller transformer core size, reduces response time during load changes, and eliminates the need for external capacitors, achieving efficient and rapid signal transmission while preventing core saturation.
Implementation Method 1
a pulse transformer 10 receives a square wave signal S to generate a power signal applied across a load 12
Implementation Method 2
the magnetic core of the pulse transformer 10 will be saturated to short-circuit the primary winding of the pulse transformer 10
Data Source
AI summary
A driving method and a driving device using the same are disclosed. The driving method controls a pulse transformer. The secondary winding of the pulse transformer is electrically connected to a control device. Firstly, positive charging electrical energy is delivered to the primary winding, thereby charging the control device. Then, the control device is disconnected from the secondary winding while the primary winding is in a high-impedance state. Finally, negative discharging electrical energy is delivered to the primary winding and the control device is electrically connected to the secondary winding, thereby discharging the control device, and the primary winding is in a low-impedance state after the step of delivering the negative discharging electrical energy to the primary winding.