Charge Pump Voltage Converter Current Limiting
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Solution Overview
Problem
DC/DC converters using capacitive charge pumps generate high-frequency harmonic disturbances due to fast charging and discharging, leading to performance loss and electromagnetic compatibility (EMC) issues in power systems.
Innovation Solution
Implementing a control circuit with current limiting means to regulate the charging switch, slowing down the switching speed and reducing high current peaks, thereby minimizing harmonic distortion and EMC problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fast charging and discharging of capacitors is used in charge pump stages, then voltage conversion efficiency is improved, but high current peaks and high-frequency harmonic disturbances are generated
Solution Approach 1:
The patent applies periodic switching action to charge and discharge capacitors in a controlled sequence through multiple stages. By using periodic clock signals to drive the switching elements, the system achieves efficient voltage conversion while distributing the current peaks over time rather than having simultaneous large current draws, thus reducing high-frequency harmonic disturbances.
Solution Approach 2:
The patent divides the voltage conversion process into multiple separate charge pump stages, each with its own capacitor and switching elements. This segmentation allows each stage to operate independently at lower current levels, preventing the generation of large combined current peaks that would cause high-frequency harmonics, while still achieving the desired overall voltage conversion efficiency.
2Power
If multiple charge pump stages are arranged in cascade, then higher output voltage is achieved, but harmonic pollution and EMC problems increase
Solution Approach 1:
The patent segments the voltage multiplication process into multiple independent charge pump stages connected in cascade. Each stage contributes a portion of the total voltage gain, allowing the system to achieve high output voltage while keeping individual stage current draws manageable. This segmentation prevents the accumulation of harmonic pollution that would occur with a single high-current stage.
Solution Approach 2:
Each charge pump stage in the cascade is driven by periodic clock signals with controlled timing relationships. This periodic operation ensures that current peaks from different stages are distributed in time rather than occurring simultaneously, reducing the overall harmonic pollution while maintaining the desired high output voltage through the cascaded configuration.
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 effectively reduces high-frequency harmonic pollution, preventing performance loss and EMC issues while maintaining efficient voltage conversion, making the system more reliable and functional.
Implementation Method 1
A voltage converter may have several charge pump stages arranged in cascade. A charge storage element of the first stage is charged upon a switching event of a driver driving the first stage.
Implementation Method 2
the charging switch is a transistor, and the current limiting means is for limiting the current flowing to or from the gate of the charging switch, thereby to limit the switching speed of the signal applied to the gate.
Data Source
AI summary
A voltage converter comprises at least two capacitive charge pump stages, each comprising a capacitor, a charging switch through which a capacitor charging current is adapted to flow, and a control circuit for controlling the charging switch.wherein the control circuit for at least one charge pump stage comprises current limiting means for limiting the current through the charging switch. By limiting the current flowing through the switch, current spikes are avoided, which reduces high frequency distortion.