Triac Gate Control Circuit Without Optocouplers or Relays

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Solution Overview

Problem

Existing voltage converter circuits, particularly those using triacs or thyristors, face inefficiencies in control and power supply, leading to suboptimal performance in converting AC to DC voltages and powering motors.

Innovation Solution

A control circuit for triacs or thyristors is developed, featuring a bipolar transistor and a driving circuit referenced to a semiconductor device, which includes a diode or MOS transistor, and a Zener diode for efficient control, potentially integrated with a processor for adaptive operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional control circuits for triacs or thyristors are used, then the circuit can perform basic voltage conversion, but the control efficiency is suboptimal and the circuit complexity is high due to optocouplers and relay-based systems

Engineering Contradiction:
Improvecontrol efficiencyVSAvoidcircuit complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent removes optocouplers and relay-based systems from the control circuit, extracting only the essential bipolar transistor and driving circuit components. This extraction eliminates unnecessary complexity while preserving the core voltage conversion function, directly resolving the contradiction between control efficiency and circuit complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces mechanical relay-based control systems with a solid-state bipolar transistor control circuit. This substitution eliminates mechanical moving parts and improves control efficiency while reducing overall circuit complexity through more efficient electronic control mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If optocouplers and relay-based systems are used in the control circuit, then isolation and control functions are provided, but the component count increases and reliability decreases

Engineering Contradiction:
Improvesystem reliabilityVSAvoidcomponent count
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes optocouplers and relay-based systems from the circuit, reducing the component count from multiple isolation and control devices to just a bipolar transistor and its driving circuit. This extraction directly improves reliability by eliminating failure-prone components while maintaining essential control functions.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The bipolar transistor control circuit is designed to provide both isolation and control functions through its inherent characteristics, eliminating the need for separate optocoupler components. This self-service approach reduces component count and improves reliability by having the transistor perform multiple functions that previously required separate dedicated components.

Inventive Principle:
Principle #25Self-service

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 solution enhances the efficiency of voltage converter circuits, improving power supply to motors by optimizing control mechanisms and reducing complexity, thus avoiding the need for optocouplers and relay-based systems, leading to increased reliability and reduced component count.

Implementation Method 1

a Zener diode for efficient control

Methodology Applied
Scientific EffectZener breakdown: Avalanche Breakdown

Implementation Method 2

A first bipolar transistor; A driving circuit of said first transistor

Methodology Applied
Scientific EffectBipolar transistor amplification:

Implementation Method 3

a voltage rectifier comprising at least a semiconductor device connected between the first reference node and a second reference node

Methodology Applied
Scientific EffectDiode rectification: Diode

Data Source

PatentEP4447320A1Control circuit of a triac or a thyristor
Publication Date: 2024.10.16 STMICROELECTRONICS INT NV
  • EP4447320A1 patent drawingFigure 1
  • EP4447320A1 patent drawingFigure 2
  • EP4447320A1 patent drawingFigure 3

AI summary

The present disclosure relates to a control circuit (210) of a triac (TR201) or thyristor having its driving reference terminal connected to a first reference node (IN202) and coupled to a voltage rectifier (202) comprising at least a semiconductor device (D204) connected between the first reference node (IN202) and a second reference node (GND-DC-200)of the control circuit comprising: - A first bipolar transistor (TB210); - A driving circuit of said first transistor (TB210) referenced to the second reference node (GND-DC-200).