Switch-Mode Voltage Regulator Buck Boost Transition Stability
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Solution Overview
Problem
Existing DC-DC converters face instability issues when transitioning between buck and boost modes, leading to unacceptable levels of disturbances like spikes and ripple in the regulated supply, and require a trade-off between bandwidth, maximum load, and responsiveness, which affects their ability to handle transient demands.
Innovation Solution
A switch-mode voltage regulator with a second control loop that includes a current-to-voltage modulator and a voltage ramp generator, allowing for smooth transition between buck and boost modes by modulating the width of pulses based on output voltage and current, thereby stabilizing the converter and reducing ripple and spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single control loop based on output voltage is used, then the converter can provide regulated supply, but instability occurs under certain load conditions and severe disturbances (ripple or spikes) are generated
Solution Approach 1:
The patent introduces a second feedback loop that monitors inductor current and feeds it back to the control circuitry. This additional feedback path allows the system to detect and respond to load conditions that cause instability, enabling the converter to maintain stability across a wider range of operating conditions while reducing harmful disturbances like ripple and spikes.
2Productivity
If bandwidth and responsiveness to transients are increased, then the converter responds better to transient demands, but instability occurs under certain load conditions
Solution Approach 1:
The dual control loop structure allows the system to maintain high responsiveness to transients through the fast-acting current feedback while the voltage feedback loop provides overall stability control. The current loop可以快速响应负载变化，而电压环路确保系统在各种负载条件下的稳定性，从而同时实现高响应性和稳定性。
3Reliability
If a second control loop is added to improve stability, then the converter can pass smoothly between buck and boost modes, but chip area and power consumption increase
Solution Approach 1:
The control circuitry is designed to perform multiple functions: it controls the switching elements for both buck and boost modes, generates the voltage ramp signal, and processes both voltage and current feedback signals. This multi-functional design allows the second control loop to be integrated into the existing architecture without requiring separate dedicated circuits, thereby minimizing the increase in chip area and power consumption while achieving smooth mode transitions.
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 enables stable operation across a wide range of input voltages without significant increases in chip area or power consumption, improving the converter's ability to handle transient demands and maintaining a stable regulated output.
Implementation Method 1
a switching system connected to a rectifier which contains an inductor
Implementation Method 2
a capacitor coupled between the regulated supply output and the negative supply
Implementation Method 3
a voltage-to-current modulator coupled to said inductor and to said voltage ramp generator
Data Source
Figure 1
Figure 2~3C
Figure 4~6
AI summary
The invention concerns a switch-mode voltage regulator, comprising : an inductor (L); a generator for producing a voltage ramp (16); circuitry (12, 13) for producing at least one pulse stream from said voltage ramp; switch control circuitry (14) for controlling switching of a current in the inductor according to said pulse stream; and a first control loop adapted to modulate the form of the voltage ramp according to the current flowing in the inductor.