Forward Fed Boost Converter for Flyback SMPS Controller Power

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Solution Overview

Problem

Existing switched mode power supplies (SMPS) face inefficiencies when supplying the controller's integrated circuit (IC) with high voltage, leading to increased losses and high dissipation due to the need for internal series regulators, which is particularly problematic in high-power density chargers.

Innovation Solution

A forward fed boost converter for flyback SMPS is implemented, where the primary side controller IC is supplied during the primary stroke from the auxiliary winding, reducing the reliance on internal series regulators and minimizing energy dissipation by using a boost type regulator with a pulse width modulator, switch, rectifying diode, inductor, and output capacitor to regulate the internal working voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high voltage is supplied to the controller's IC, then the controller can operate, but internal series regulator losses increase and dissipation becomes high

Engineering Contradiction:

Improvecontroller operationVSAvoidinternal series regulator losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The power supply system is segmented into two independent regulators: a first switching regulator that powers the controller IC during primary stroke, and a second switching regulator that powers auxiliary circuits during secondary stroke. This segmentation allows each regulator to operate independently at optimized voltage levels, eliminating the need for the controller IC to tolerate high voltage dissipation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first switching regulator is activated during the primary stroke (before the secondary stroke) to pre-charge the controller IC and its associated capacitors. This preliminary action ensures the controller IC is fully powered and ready to operate when the secondary stroke begins, eliminating the need for an internal series regulator to handle voltage transitions.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If high voltage is supplied to the controller's IC, then the controller can operate, but dissipation inside the IC becomes high

Engineering Contradiction:

Improvecontroller operationVSAvoiddissipation inside the IC

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first switching regulator acts as an intermediary between the high voltage auxiliary winding and the controller IC. It converts the high voltage from the auxiliary winding to a suitable operating voltage for the controller IC, thereby protecting the IC from direct exposure to high voltage and the associated heat dissipation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If internal series regulator is used to supply the controller's IC, then the controller can operate, but losses increase

Engineering Contradiction:

Improvecontroller operationVSAvoidregulator losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The internal series regulator is extracted and replaced with an external first switching regulator. This external regulator is specifically designed to operate during the primary stroke and can efficiently manage the power conversion without the losses inherent in internal series regulators, thereby reducing overall system losses while maintaining controller operation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The operating parameters of the power supply system are changed by introducing phase-based regulation: the first switching regulator operates during primary stroke when the controller IC requires power, while the second switching regulator operates during secondary stroke. This parameter change allows each regulator to operate at optimized efficiency points, reducing total losses compared to a continuous internal series regulator.

Inventive Principle:

Principle #35Parameter changes

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

This approach significantly reduces losses and dissipation in the primary side IC, improving total efficiency and allowing for higher power density chargers with reduced IC package size and lower maximum IC voltages.

Implementation Method 1

a transformer including a primary side winding on the primary side, a secondary side winding on a secondary side, and an auxiliary winding on the primary side connected to a first switching regulator, wherein the first switching regulator is supplied during a primary stroke from the auxiliary winding

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The PWM regulator is configured to regulate an internal working voltage of the boost type regulator to a fixed voltage which is greater than or equal to an input voltage of the boost type regulator

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentUS10396677B2Forward fed boost converter for flyback switched mode power supply and method thereof

Publication Date: 2019.08.27 NXP BV

AI summary

Various embodiments relate to a flyback type SMPS including a primary side controller on a primary side, a first switch on the primary side and a transformer including a primary side winding on the primary side, a secondary side winding on a secondary side and an auxiliary winding on the primary side connected to a first switching regulator wherein the first switching regulator is supplied during a primary stroke from the auxiliary winding when the first switch is on.