Flyback Converter Current Control With Variable Peak Reference

Solution Overview

Problem

Existing power converters struggle to maintain a constant average output current independent of changes in input or output conditions, particularly in flyback converters, which require improved current mode control for stability.

Innovation Solution

A flyback converter system with a switching system and reference controller that generates a variable peak current amplitude based on output voltage variations, regulating the input current to achieve a constant average output current through a flyback inductor, using a programmable multiplier to adjust the peak amplitude according to input and output conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional voltage mode control or current mode control is used in flyback converters, then the converter can operate with basic feedback control, but the output current cannot maintain constant average value independent of input or output voltage changes

Engineering Contradiction:

Improveoutput current stabilityVSAvoidresponse to input/output voltage variations

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements a feedback control mechanism where the output voltage is sampled and fed back to the reference generator. The reference generator adjusts the peak current reference based on the sampled output voltage, creating a closed-loop system that maintains constant average output current despite variations in input or output voltage conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent dynamically changes the peak current reference parameter based on output voltage conditions. The reference generator modifies the peak current amplitude in response to output voltage variations, allowing the converter to adapt its operating parameters to maintain stable output current across different operating conditions.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the peak current amplitude is fixed, then the control system is simple, but the output current varies with input voltage or output voltage changes

Engineering Contradiction:

Improveconstant average output currentVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent transitions from a fixed peak current amplitude to a dynamic, variable peak current reference. The reference generator continuously adjusts the peak current amplitude based on real-time output voltage sampling, enabling the system to maintain constant average output current while adapting to changing operating conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements a feedback control mechanism where the output voltage is sampled and fed back to the reference generator. The reference generator adjusts the peak current reference based on the sampled output voltage, creating a closed-loop system that maintains constant average output current despite variations in input or output voltage conditions.

Inventive Principle:

Principle #23Feedback

3Speed

If current mode control is used for stability, then transient response improves, but the system still requires output voltage feedback and cannot maintain constant average current independent of voltage variations

Engineering Contradiction:

Improvetransient responseVSAvoidcurrent regulation independence

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent implements a feedback control mechanism where the output voltage is sampled and fed back to the reference generator. The reference generator adjusts the peak current reference based on the sampled output voltage, creating a closed-loop system that maintains constant average output current despite variations in input or output voltage conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent dynamically changes the peak current reference parameter based on output voltage conditions. The reference generator modifies the peak current amplitude in response to output voltage variations, allowing the converter to adapt its operating parameters to maintain stable output current across different operating conditions.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250323581A1Voltage converter output current regulation system

Publication Date: 2025.10.16 TEXAS INSTRUMENTS INC

AI summary

In a described example, a circuit includes a switching system and a reference controller. The reference controller includes an output voltage sampler and a variable reference generator. The switching system is configured to activate a primary switch to provide an input current through a flyback inductor in response to an instantaneous amplitude of an output current falling below a predetermined threshold. Additionally, the switching system is configured to deactivate the primary switch in response to the input current increasing greater than a variable peak current amplitude. The output voltage sampler is configured to sample an output voltage of the flyback inductor in response to the deactivation of the primary switch. The variable reference generator is configured to generate the variable peak current amplitude based on the output voltage of the flyback inductor.