Startup Control Circuit for LED Drivers

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Solution Overview

Problem

Existing startup control circuits for LED drivers do not effectively manage startup voltage generation and short-circuit detection, leading to inefficient charging and potential damage from short-circuits.

Innovation Solution

A startup control circuit with a charge switch element and a short-circuit detecting and switching unit, comprising first and second switch elements, diodes, and capacitors, which generates and regulates startup voltage and detects short-circuits to prevent further charging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a startup voltage generation circuit with a capacitor is used to provide power to the control circuit, then the control circuit can be powered during startup, but the capacitor may become shorted causing heat generation and potential damage to charging components

Engineering Contradiction:

Improvestartup voltage generation reliabilityVSAvoidshort-circuit damage and heat generation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by detecting potential short-circuit conditions before they cause damage. The detection circuit monitors the capacitor status in advance, and the control circuit preemptively stops charging when a short-circuit condition is detected, preventing heat generation and damage to charging components rather than reacting after damage occurs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary detection circuit and control mechanism between the charging circuit and the capacitor. This intermediary system monitors voltage conditions and controls the charging process, acting as a protective mediator that prevents direct damage to charging components when capacitor short-circuit occurs

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If continuous charging current is supplied to the startup capacitor, then the capacitor can maintain sufficient voltage for control circuit operation, but charging continues even when the capacitor is shorted causing energy waste and component damage

Engineering Contradiction:

Improvecapacitor charging efficiencyVSAvoidenergy waste during short-circuit

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent implements feedback control by having the detection circuit continuously monitor the capacitor voltage and feed this information back to the control circuit. When the feedback indicates a short-circuit condition (abnormal voltage level), the control circuit automatically adjusts or stops the charging current, preventing energy waste while ensuring proper charging under normal conditions

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies dynamics by making the charging current dynamic rather than continuous. The control circuit adjusts the charging current based on real-time detection of capacitor status, increasing current when needed for startup and stopping or reducing it when short-circuit is detected, optimizing energy usage while preventing waste

Inventive Principle:

Principle #15Dynamics

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

Ensures safe and efficient startup voltage generation by preventing short-circuit damage and optimizing charging processes, enhancing the reliability of LED drivers.

Implementation Method 1

a startup voltage generation circuit (101) having a first capacitor (C41, C42) and a first output terminal (1011), wherein the first capacitor (C41, C42) is charged to generate a startup voltage

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

a short-circuit detecting and switching unit (102), which is connected to the first output terminal (1011) of the startup voltage generation circuit (101), and when the first capacitor (C41, C42) of the startup voltage generation circuit is shorted, the short-circuit detecting and switching unit turns off the charge switch element

Methodology Applied

Scientific EffectElectrical short-circuit detection:

Data Source

PatentEP3596816B1Startup control circuit

Publication Date: 2021.03.31 TRIDONIC GMBH & CO KG

Figure 1
Figure 2

AI summary

A startup control circuit (100), used for supplying a startup voltage for a control circuit (U20) of a switch power supply (200), which comprises: a startup voltage generation circuit (101) having a first capacitor (C41, C42) and a first output terminal (1011), the first capacitor (C41, C42) being charged to generate a startup voltage, the startup voltage being outputted from the first output terminal (1011) of the startup voltage generation circuit (101) to the control circuit (U20); a charge switch element (M21), a gate of which being connected to a charge node (A), when the charge switch element (M21) is turned on, it supplies a current for charging the first capacitor (C41, C42); and a short-circuit detecting and switching unit (102), which is connected to the first output terminal (1011) of the startup voltage generation circuit (101), and when the first capacitor (C41, C42) of the startup voltage generation circuit (101) is shorted, the short-circuit detecting and switching unit (102) turns off the charge switch element (M21), so as to stop supplying the current for charging the first capacitor (C41, C42).