LED Driver Standby Power Reduction via BLON Voltage Control
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Solution Overview
Problem
The high standby power consumption of liquid crystal display TVs, particularly due to the LED driving chip's operational functions remaining active during standby conditions, exceeds regulatory limits, necessitating a reduction in power loss and consumption.
Innovation Solution
A method involving a comparator and integrator circuit that samples the brightness control signal to control a field-effect transistor, which pulls down the voltage of the high voltage switch terminal of the LED driving chip, effectively shutting off unnecessary functions and reducing power consumption during standby.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the LED driving chip functions remain active during standby condition, then the TV can quickly transition to operation mode, but the standby power consumption increases
Solution Approach 1:
The circuit performs preliminary action by detecting the standby state through the PDIM signal and proactively pulling down the BLON signal before the user actually turns off the TV. This advance preparation allows the TV to quickly transition to operation mode when needed while maintaining low standby power consumption, as the circuit is already in the correct state to enable immediate operation.
2Reliability
If the BLON signal is kept in high level during standby, then the LED driving chip functions are available, but power loss of the LED driving chip increases
Solution Approach 1:
The circuit implements feedback by continuously monitoring the PDIM signal state and automatically adjusting the BLON signal accordingly. When PDIM indicates standby condition (low duty cycle), the feedback mechanism triggers the integrator and comparator to pull down BLON, reducing power consumption. When PDIM indicates operation mode, BLON is restored to high level, ensuring function availability. This closed-loop feedback resolves the contradiction by dynamically adapting the BLON state to actual usage conditions.
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 the standby power consumption of liquid crystal display TVs by shutting off most functions of the LED driving chip during standby, aligning with energy-saving regulations and conserving limited electricity resources.
Implementation Method 1
an integrator, wherein the integrator comprises a first input terminal, a second input terminal, and a second output terminal; electrically connecting the first input terminal of the integrator to the brightness control terminal of the LED driving chip
Implementation Method 2
a comparator, wherein the comparator comprises a non-inverting input terminal, an inverting input terminal, and a first output terminal; electrically connecting the second output terminal to the inverting input terminal of the comparator
Implementation Method 3
electrically connecting the first output terminal to the field-effect transistor, and electrically connecting the field-effect transistor to the high voltage switch terminal and grounding line of the LED driving chip
Data Source
AI summary
The present invention provides a method for reducing standby power consumption, which includes providing an LED driving chip; connecting an integrator to a brightness control terminal of the driving chip, connecting the integrator to a comparator, connecting the comparator to a field-effect transistor, connecting the field-effect transistor to the driving chip; connecting the driving chip to a first power source, connecting a high voltage switch terminal of the driving chip via a resistor to a second power source, connecting the brightness control terminal and the integrator to a control source, and connecting the integrator to a reference voltage; and conducting the first and second power sources, the control source, and the reference voltage to allow the integrator and the comparator to pull down voltage of the high voltage switch terminal of the driving chip according to the conduction of the field-effect transistor by a signal of the brightness control terminal.