Triangular Wave Injection for Buck Converter Voltage Stability
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Solution Overview
Problem
Conventional switching controllers using high-side and low-side FETs in buck converters face instability due to the ripple in output voltage, which is undesirable in certain applications, and the equivalent series resistance (ESR) of capacitors is often out of control, depending on manufacturing methods and temperature.
Innovation Solution
A switching controller design that incorporates a first and second switch, connected through a common inductor to a load, with a triangular wave generator providing control signals to stabilize the load voltage by switching between on and off states based on feedback voltage comparisons with a target voltage, using a triangular wave signal with both positive and negative information to maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional switching controllers use ripple in output voltage to regulate output current, then voltage regulation is achieved, but output voltage stability deteriorates due to undesirable ripple
Solution Approach 1:
The patent extracts the harmful ripple component from the output voltage regulation mechanism. Instead of using the ripple as the control signal, the invention uses a separate triangular wave signal that is injected into the feedback path, thereby removing the dependency on output voltage ripple while maintaining regulation accuracy.
Solution Approach 2:
The patent introduces an intermediary triangular wave signal as a mediator between the control system and the output voltage regulation. This triangular wave serves as a reference signal that replaces the direct use of output ripple, allowing voltage regulation without the harmful effects of ripple propagation.
2Stability of the object's composition
If equivalent series resistance (ESR) of capacitor is increased to control output voltage phase, then stable operation is achieved, but manufacturing control becomes difficult due to dependencies on manufacturing methods and temperature
Solution Approach 1:
The patent changes the control parameter from ESR (which is difficult to control) to a triangular wave signal parameters (amplitude and frequency) that can be precisely controlled through electronic circuitry. This allows stable operation to be achieved without relying on capacitor ESR variations.
Solution Approach 2:
The patent replaces the passive ESR-based stabilization mechanism with an active electronic control system using triangular wave injection. This substitution transitions from relying on physical capacitor properties to using controllable electrical signals, thereby improving manufacturing precision.
3Duration of action of moving object
If capacitor delays output voltage relative to output current, then phase alignment is achieved, but output voltage stability deteriorates
Solution Approach 1:
The patent employs feedback control by injecting the triangular wave signal into the feedback path. The triangular wave is synchronized with the switching cycle and provides real-time phase information, allowing the controller to maintain proper voltage-current phase alignment while actively compensating for stability issues through closed-loop control.
Data Source
AI summary
The present invention discloses a voltage control method. At first, the load voltage of the load is divided to generate a feedback voltage. The feedback voltage and a triangular wave of a triangular wave periodic signal, including the positive voltage and negative voltage, are combined to generate a sum signal. The sum signal is compared with a target voltage, and when the sum signal is less than the target voltage signal, a control signal is generated to control the switches to turn on or off. Finally, the switch receives the control signal and accordingly providing an input voltage to update and stabilize the load voltage.