LED Driver IC Voltage Regulation for Ultra-Low Standby Power

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Solution Overview

Problem

Conventional smart home LED switches consume excessive power in standby mode due to the need to remain active for wake-up signals, which contradicts the goal of achieving ultra-low standby power consumption required by regulations like Energy Star certification and California Code of Regulations Title 20.

Innovation Solution

The implementation of an integrated circuit (IC) that regulates output voltage to one-third of the nominal operating voltage of an LED, using transistors to inductively couple or decouple the main power supply bus voltage from a transformer, and selectively providing power supply input voltage to the IC based on threshold voltages to maintain the LED in a low power mode, ensuring it remains functional for wake-up signals while minimizing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the switch remains active to respond to wake-up signals in smart home applications, then the reliability of remote control is improved, but the power consumption in standby mode increases

Engineering Contradiction:

Improveresponsiveness to wake-up signalsVSAvoidstandby power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic power management by transitioning the LED driver circuit between different operational states (active, standby, and off states) based on control signals. The circuit can be fully active to respond to wake-up signals, partially active in standby mode to minimize power consumption while maintaining responsiveness, and completely off when no control is needed, thus resolving the contradiction between reliability and power consumption

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes operational parameters such as switching frequency, duty cycle, and power supply voltage to different levels depending on the operational state. By adjusting these parameters dynamically, the circuit maintains the ability to respond to wake-up signals while significantly reducing power consumption during standby periods, addressing the contradiction between reliability and energy use

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If the LED is completely turned off to minimize power consumption, then the power saving is improved, but the ability to respond to wake-up signals deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoidresponsiveness to control signals

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent segments the power management into multiple operational modes (full power, standby, and off states). The circuit can be completely off to minimize power consumption while a separate control circuit remains active to detect wake-up signals. When a wake-up signal is detected, the main LED driver is reactivated, thus achieving both low power consumption and maintained responsiveness through functional segmentation

Inventive Principle:

Principle #1Segmentation

3Use of energy by moving object

If the output voltage is reduced to one-third of nominal voltage to achieve dim-to-off state, then the power consumption is improved, but the LED brightness deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoidLED brightness

Core Design Contradiction:

Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The patent uses periodic pulse signals to drive the LED in dim-to-off state. By applying short duty cycle pulses at reduced voltage (one-third of nominal), the LED appears dim or off to human perception while consuming significantly less power. The periodic nature of the pulses maintains LED functionality and responsiveness while achieving the desired low brightness and low power consumption state

Inventive Principle:

Principle #19Periodic action

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 effectively reduces power consumption to ultra-low levels, such as 75 mW in standby mode, while maintaining the LED in a 'light-off' state, compliant with regulatory standards and extending device lifespan by minimizing idle power usage.

Implementation Method 1

a first transistor configured to be switched on or off by the IC to inductively couple or decouple a main power supply bus voltage from a primary winding of a transformer to a secondary winding of the transformer connectable to the LED

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS10375780B2Controlling output voltage to achieve ultra-low standby power in dim-to-off LED applications

Publication Date: 2019.08.06 DIALOG SEMICONDUCTOR INC

AI summary

An electronic device is provided that includes an integrated circuit (IC) configured to regulate an output voltage for powering a light emitting diode (LED). A first transistor is configured to be switched on or off by the IC to inductively couple or decouple a main power supply bus voltage from a primary winding of a transformer to a secondary winding of the transformer connectable to the LED. A second transistor is coupled between the IC and the main power supply bus voltage, and configured to be switched on or off by the IC to selectively provide an IC power supply input voltage to the IC.