Capacitor-Based Charge Pump Power Supply for Low Noise
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Solution Overview
Problem
Conventional switching power supplies for portable electronic devices, such as ultrasound imaging systems, are often bulky, inefficient, and generate significant noise due to electromagnetic interference and harmonics, requiring extensive countermeasures like synchronization and passive filtering.
Innovation Solution
A compact and efficient power supply configuration using low impedance switches, LDO regulators, and charge pump topology to generate various voltage levels with minimal noise, eliminating heavy components like inductors and synchronizing charge pumping events with device operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If switching power supplies with large passive components are used, then voltage conversion is achieved, but the device becomes bulky and consumes large current volume
Solution Approach 1:
The patent removes the large inductor component from the power supply circuit, replacing it with a topology that uses only capacitors and switches. This extraction of the bulky passive component directly reduces device volume while maintaining voltage conversion functionality through the capacitor-based energy storage and transfer mechanism
Solution Approach 2:
The patent replaces the magnetic field-based energy storage (inductor) with an electric field-based energy storage (capacitor) system. This substitution eliminates the need for large magnetic components, significantly reducing the physical volume of the power supply while achieving the same power conversion function
2Power
If switching power supplies are used, then voltage conversion is achieved, but electromagnetic interference and noise are generated
Solution Approach 1:
The patent extracts and removes the switching transistor that generates electromagnetic interference and noise. By replacing the switching mechanism with a diode-based rectification system, the harmful electromagnetic emissions are eliminated while voltage conversion is still achieved through the capacitor charge-discharge cycles
Solution Approach 2:
The patent converts the potentially harmful rapid switching transients into beneficial controlled charge transfer cycles. The diode-based system naturally limits current spikes and electromagnetic radiation, transforming what would be noise-generating switching events into smooth, controlled energy transfer processes that benefit image quality
3Power
If switching power supplies are used, then voltage conversion is achieved, but efficiency is reduced due to losses
Solution Approach 1:
The patent replaces the resistive switching mechanism with a diode-based rectification system that has lower forward voltage drops. This substitution reduces conduction losses significantly, improving overall energy efficiency while maintaining the voltage conversion function through capacitor-based energy transfer
Solution Approach 2:
The patent employs periodic charging and discharging of capacitors to achieve voltage conversion. This periodic action allows energy to be stored and transferred in controlled cycles, minimizing losses compared to continuous switching operations, and enabling efficient power conversion through resonant-like charge transfer
4Adaptability or versatility
If cascade of DC-to-DC converters is used, then multiple voltage rails are generated, but complexity and inefficiency increase
Solution Approach 1:
The patent designs a universal capacitor-based power conversion stage that can generate multiple voltage rails simultaneously. By using a single multi-capacitor topology with diode networks, the system can produce various voltage levels (e.g., positive and negative rails) from a single input, eliminating the need for multiple cascaded converters and reducing overall circuit complexity
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 reduces energy losses, simplifies the circuit configuration, minimizes electrical noise, and eliminates bulky interference-producing components, resulting in a more efficient and quieter power supply for portable devices.
Implementation Method 1
charge pump topology to generate various voltage levels
Implementation Method 2
low impedance switches
Data Source
AI summary
Power supplies for electronic devices (e.g., portable ultrasound devices) are disclosed herein. In one embodiment, a stack of batteries and one or more switches between the batteries can change a voltage provided to a terminal that is connectable to a load. A charge pump comprising a number of capacitors are connected by switches. In one configuration, the switches are set so that each capacitor is charged from a common voltage source. In another mode, the switches are connected such that capacitors can be connected in series to provide a multiple of the charging voltage to the load.