Buck Converter Ramp Generation Using Output Feedback

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional power converters with active ramp generator circuits have high output impedance, resulting in poor transient response due to the lack of utilization of the output signal in generating the ramp signal.

Innovation Solution

A power converter design that incorporates a ramp generator circuit utilizing passive impedance circuits and the output signal to generate the ramp signal, improving transient response and reducing power consumption by allowing the control circuit to adjust the control signal based on the output, input, and reference signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an active ramp generator circuit is used, then the ramp signal can be generated, but the output impedance is high resulting in poor transient response

Engineering Contradiction:

Improvetransient responseVSAvoidoutput impedance

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent implements feedback by utilizing the output signal of the power converter to generate the ramp signal. The ramp generator circuit receives the output signal and uses it to create the ramp waveform, establishing a direct feedback loop that improves transient response by dynamically adjusting the ramp signal based on actual output conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs self-service by using its own output signal to generate the control ramp signal. The power converter's output is fed back to the ramp generator, which then uses this signal along with the input signal to create the necessary ramp waveform for PWM control, eliminating the need for external active components.

Inventive Principle:

Principle #25Self-service

2Reliability

If passive impedance circuits are used to generate ramp signal, then transient response is improved, but power consumption increases

Engineering Contradiction:

Improvetransient responseVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The ramp generator circuit performs multiple functions: it generates the ramp signal for PWM control, utilizes the output signal for feedback, and operates using passive impedance circuits that consume minimal power. This multi-functionality allows the same circuit to improve transient response while maintaining low power consumption through efficient use of available signals.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the operational parameters by using passive impedance circuits instead of active amplifying components. By utilizing resistors, capacitors, and the inherent characteristics of the power stage, the circuit achieves ramp signal generation with significantly reduced power consumption compared to active implementations.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11973425B2Ramp generation in buck converters

Publication Date: 2024.04.30 NOVATEK MICROELECTRONICS CORP

AI summary

A power converter includes a power stage circuit, a ramp generator circuit, and a control circuit. The power stage circuit generates an output signal according to an input signal and a control signal. The ramp generator circuit generates a ramp signal according to the control signal, the input signal, and the output signal. The control circuit generates the control signal according to the output signal, a reference signal, and the ramp signal.