Buck-Boost Switching Regulator for Stable Voltage Control
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Solution Overview
Problem
Voltage buck-boost switching regulators face instability and increased complexity due to wide application voltage ranges and high current loads, particularly in Li-ion battery applications, leading to challenges in maintaining stable, high-speed, and high-efficiency constant-voltage output operations without using large-scale, high-cost phase compensation circuits.
Innovation Solution
A voltage buck-boost switching regulator design featuring a first and second switching circuit for voltage reducing and boosting, respectively, along with an error amplifier, current sense circuit, and variable sawtooth wave generators, allowing for stable high-speed constant-voltage output using a single integrator for phase compensation, and enabling smooth transitions between voltage reducing and boosting modes without switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a voltage buck-boost switching regulator is designed to operate across a wide voltage range (4V to 2.5V battery voltage), then the adaptability is improved, but the stability deteriorates due to difficulty in maintaining stable constant-voltage output under varying input conditions
Solution Approach 1:
The patent implements dynamic operation mode switching between voltage reducing mode and voltage boosting mode based on real-time comparison of input voltage Vi and output voltage Vo. The switching regulator dynamically adjusts its operating state to maintain stable output voltage across the wide input voltage range from 4V to 2.5V, resolving the contradiction between adaptability and stability.
Solution Approach 2:
The patent changes the operating parameters by switching between two distinct operational modes (voltage reducing and voltage boosting) depending on the input voltage level. This parameter change approach allows the system to maintain stable constant-voltage output while adapting to the wide battery voltage range, effectively resolving the technical contradiction.
2Stability of the object's composition
If a complex phase compensation circuit is used to maintain stability, then the stability is improved, but the device complexity increases and chip size increases
Solution Approach 1:
The patent extracts and eliminates the complex phase compensation circuit from the feedback loop by implementing current-mode control with separate PWM controllers for voltage reducing and voltage boosting modes. This extraction removes the source of complexity while maintaining feedback loop stability through the simplified control architecture.
Solution Approach 2:
The patent segments the feedback control into two independent PWM controllers (first PWM controller for voltage reducing mode, second PWM controller for voltage boosting mode), each optimized for its specific operating range. This segmentation eliminates the need for a complex unified phase compensation circuit, reducing device complexity while maintaining stability in each mode.
3Stability of the object's composition
If separate control circuits are used for voltage reducing and voltage boosting modes, then the stability in each mode is improved, but the device complexity increases
Solution Approach 1:
The patent implements a universal switching regulator architecture that can operate in both voltage reducing and voltage boosting modes using a common inductor, capacitors, and basic circuit topology. The multi-functionality is achieved through mode-dependent switching of transistors, reducing overall device complexity while maintaining stable control in each specific mode through dedicated PWM controllers.
4Speed
If the switching regulator operates at high frequency for high-speed response, then the speed is improved, but the loss of energy increases due to switching losses
Solution Approach 1:
The patent implements periodic switching action with dedicated PWM controllers that generate precise on/off signals for the switching transistors. The periodic control maintains high-speed response while optimizing the duty cycle to minimize switching losses, achieving high efficiency through synchronized switching patterns in both voltage reducing and voltage boosting modes.
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 stable, high-speed, and high-efficiency constant-voltage output across a wide range without the need for complex phase compensation circuits, reducing semiconductor chip size and cost while maintaining high efficiency and stability during mode transitions.
Implementation Method 1
a first switching circuit for voltage reducing connected between the voltage input terminal and one terminal of an inductance element; a second switching circuit for voltage boosting connected between the other terminal of the inductance element and the voltage output terminal
Data Source
AI summary
A stable, high-speed, high-efficiency constant voltage is provided without a complicated, large-scale, high-cost phase compensation circuit over a wide range of operating conditions. This voltage buck-boost switching regulator consists of a pair of voltage reducing transistors, a pair of voltage boosting transistors, inductance coil, output capacitor and controller. The controller has the following parts for performing PWM control of constant voltage for voltage reducing transistors and voltage boosting transistors: an output voltage feedback circuit, an inductor current sense circuit, a variable sawtooth wave signal generator, switching controllers, and a voltage boosting driver.