Parallel LED Drivers for Fast Current Settlement

Solution Overview

Problem

Existing LED driver systems face challenges in maintaining stable and fast current settlement due to large parasitic capacitance when supplying high constant currents, which can lead to reduced stability and longer settlement times.

Innovation Solution

A Light Emitting Diode (LED) driver apparatus utilizing multiple LED drivers connected in parallel, each comprising a resistor, a switching unit (FET), and a comparator, with a controller to manage current amplitude and a PWM signal generator for efficient current supply, reduces parasitic capacitance and ensures stable and rapid current settlement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a single constant current source is used to supply large current to LED array, then the current supply capability is improved, but the parasitic capacitance increases causing reduced stability and longer settlement time

Engineering Contradiction:

Improvecurrent supply capabilityVSAvoidcurrent stability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent divides a single constant current source into multiple parallel constant current sources. Each source supplies current to a subset of LED strings, reducing the current burden on each individual source. This segmentation reduces the parasitic capacitance of each transistor, thereby improving current stability and reducing settlement time while maintaining the total current supply capability.

Inventive Principle:

Principle #1Segmentation

2Power

If a single constant current source is used to supply large current to LED array, then the current supply capability is improved, but the settlement time increases

Engineering Contradiction:

Improvecurrent supply capabilityVSAvoidsettlement time

Core Design Contradiction:

PowerVSLoss of time

Solution Approach 1:

The patent divides a single constant current source into multiple parallel constant current sources. Each source supplies current to a subset of LED strings, reducing the current burden on each individual source. This segmentation reduces the parasitic capacitance of each transistor, thereby improving current stability and reducing settlement time while maintaining the total current supply capability.

Inventive Principle:

Principle #1Segmentation

3Reliability

If multiple LED drivers are connected in parallel, then the parasitic capacitance is reduced improving stability, but the device complexity increases

Engineering Contradiction:

Improvecurrent stabilityVSAvoiddriver circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides a single constant current source into multiple parallel constant current sources. Each source supplies current to a subset of LED strings, reducing the current burden on each individual source. This segmentation reduces the parasitic capacitance of each transistor, thereby improving current stability and reducing settlement time while maintaining the total current supply capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The control circuit is designed to universally control multiple parallel LED drivers using a unified control architecture. The controller generates control signals that can be applied to multiple drivers, and the drivers share common circuit elements such as the LED array connection structure. This universal design approach manages the complexity by providing a standardized control method that can be scaled to different numbers of parallel drivers.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS9875697B2Parallel constant current LED driving units for driving a LED string and method of performing the same

Publication Date: 2018.01.23 MAGNACHIP SEMICON LTD

AI summary

A Light Emitting Diode (LED) driver apparatus and a method of driving an LED array are provided. A Light Emitting Diode (LED) driver apparatus includes: a DC-DC converter configured to supply a driving voltage to an LED array, a plurality of LED drivers configured to drive the LED array according to a dimming signal, in which the plurality of LED drivers are connected to one another in parallel to supply currents to the LED array.