Voltage Converter Ripple Injection Circuit Stabilizes Output
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Solution Overview
Problem
Conventional buck voltage converters experience unsteady ripple in the output signal due to low effective series resistance (ESR) in capacitors, leading to reduced quality of the step-down output voltage.
Innovation Solution
Incorporation of a ripple injection circuit and a constant on time signal generator that generates driving signals based on the ripple portion of the output signal, a reference signal, and a ramp voltage or current, to control the switching of transistors and stabilize the output ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low ESR capacitor is used in the voltage converter, then the capacitor's performance is improved, but the ripple portion of the feedback voltage becomes extremely unspicuous and the ripple phenomenon on the output voltage becomes unsteady
Solution Approach 1:
The patent introduces an artificial ripple signal as an intermediary element to compensate for the insufficient natural ripple caused by low ESR capacitors. This artificial ripple signal serves as a mediator between the capacitor and the control system, providing the necessary ripple information for stable control without requiring high ESR capacitors.
Solution Approach 2:
The patent changes the parameter of ripple signal characteristics by generating an artificial ripple signal with specific amplitude and frequency characteristics. This allows the system to maintain stable ripple phenomenon using low ESR capacitors by adjusting the ripple signal parameters rather than relying on capacitor ESR.
2Device complexity
If conventional voltage converter control is used, then the circuit structure is simple, but the output voltage ripple becomes unsteady when using low ESR capacitors
Solution Approach 1:
The artificial ripple signal generator acts as an intermediary component that bridges the gap between the low ESR capacitor and the control system. This additional component enables stable ripple control while maintaining relatively simple circuit architecture.
Solution Approach 2:
The patent implements feedback control where the artificial ripple signal is fed back to the control system to regulate the output voltage. This feedback mechanism ensures stable ripple phenomenon by continuously adjusting the control signals based on the artificial ripple signal characteristics.
Data Source
AI summary
A voltage converter includes a constant on time signal generator, a first transistor, a second transistor, an inductor, and a ripple injection circuit. The constant on time signal generator generates a first driving signal and a second driving signal. The ripple injection circuit receives an output signal and generates a ripple injection signal. The constant on time signal generator generates the first and second driving signals according to the ripple injection signal, the output signal, and a reference signal.