Variable Switched DC-DC Converter for Noise Reduction
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Solution Overview
Problem
Conventional DC-DC converters, particularly in portable devices like mobile phones, face challenges in minimizing size and weight while generating multiple discrete voltage levels efficiently, often resulting in spurious output signals that can interfere with frequency-sensitive operations.
Innovation Solution
A variable switched DC-DC converter using a switch matrix and control logic that dynamically adjusts switch states and frequencies based on mode control signals, eliminating the need for large inductive filters and optimizing power amplifier biasing for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a PWM-based DC-DC converter is used to generate multiple discrete voltage levels, then the number of output voltages can be increased without significantly more inductors and capacitors, but a relatively large spectrum of spurious output signals is generated that can adversely affect the operation of frequency-sensitive devices
Solution Approach 1:
The patent employs a dynamic switching mechanism where the DC-DC converter can switch between different operating modes (buck, boost, buck-boost) based on the desired output voltage level. This dynamic reconfiguration of the circuit topology allows generation of multiple discrete voltage levels while maintaining clean output by avoiding the continuous high-frequency switching characteristic of PWM that generates spurious signals.
Solution Approach 2:
The invention replaces the PWM-based electronic switching mechanism with a mechanical-like discrete switching approach using MOSFETs that operate in fully on or fully off states rather than rapid pulse-width modulation. This substitution eliminates the high-frequency spectral content associated with PWM while still achieving voltage conversion through controlled switching sequences.
2Object-generated harmful factors
If filters with relatively large capacitances and inductances are included in a PWM-based DC-DC converter to minimize spurious signals, then the spurious output signals are reduced, but the size and weight of the converter increases making it undesirable for portable devices
Solution Approach 1:
The patent replaces the need for large filtering inductors and capacitors by eliminating PWM operation entirely. The discrete switching mechanism produces inherently cleaner output signals that require minimal filtering, thus removing the weight penalty associated with large filter components while still achieving the goal of minimizing spurious signals.
3Adaptability or versatility
If a switched-mode DC-DC converter employs a relatively large number of inductors and capacitors to generate multiple discrete voltage levels, then the number of output voltages can be increased, but the size and weight of the converter increases making it undesirable for portable devices
Solution Approach 1:
The patent implements a universal DC-DC converter topology that can operate in multiple modes (buck, boost, buck-boost) using the same set of inductors and capacitors. By reconfiguring the switching connections, a single inductor and capacitor can serve multiple voltage conversion functions, eliminating the need for separate components for each voltage level and significantly reducing overall component count and weight.
Solution Approach 2:
The converter uses dynamic reconfiguration of the circuit topology through controlled switching of MOSFETs to achieve different voltage conversion ratios. This dynamic switching allows the same physical components to provide multiple discrete output voltage levels, reducing the need for additional inductors and capacitors that would otherwise be required for each voltage level.
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 output noise spectrum, enhances power efficiency, and extends battery life by dynamically selecting switch modes and frequencies, allowing for a continuous range of output voltages without the need for large inductive components.
Implementation Method 1
The switching circuitry can convert one DC voltage level to another by storing the input energy momentarily in inductors and/or capacitors and then releasing that energy to the output at a different voltage
Data Source
AI summary
A voltage converter can be switched among two or more modes to produce an output voltage tracking a reference voltage that can be of an intermediate level between discrete levels corresponding to the modes. One or more voltages generated from a power supply voltage, such as a battery voltage, can be compared with the reference voltage to determine whether to adjust the mode. The reference voltage can be independent of the power supply voltage.