Gamma Reference Voltage Circuit Power Management for Low Scan Rate Displays

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Solution Overview

Problem

The challenge in electronic devices, particularly in displays, is to minimize power consumption as battery capacity is limited and devices are miniaturized, necessitating reduced power usage in power management devices like PMICs, especially in non-constant power supply devices such as mobile communication devices and notebook computers.

Innovation Solution

A power management device that disables the gamma reference voltage generation circuit during the vertical blank period of a frame when the display device operates at a low scan rate, transitioning the output terminal to a high impedance state to reduce power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the gamma reference voltage generation circuit operates continuously, then the display device can maintain stable gamma voltage output, but power consumption increases

Engineering Contradiction:

Improvegamma voltage stabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The gamma reference voltage generation circuit operates periodically rather than continuously. It generates gamma reference voltage only during the vertical active period of each frame and enters a standby state during the vertical blank period, creating a periodic on-off pattern that reduces power consumption while maintaining necessary functionality during active display periods

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The circuit transitions between different operational states dynamically based on the display timing signal. During the vertical active period, the circuit is enabled and outputs gamma reference voltage. During the vertical blank period, the circuit is disabled and the output terminal enters high impedance state, creating a dynamic adaptation to operational requirements

Inventive Principle:

Principle #15Dynamics

2Use of energy by moving object

If the gamma reference voltage generation circuit is disabled during vertical blank period, then power consumption is reduced, but gamma voltage output may be affected

Engineering Contradiction:

Improvepower consumptionVSAvoidgamma voltage output stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The gamma reference voltage is generated in advance during the vertical active period before the vertical blank period begins. This preliminary generation ensures that the gamma voltage is ready and stable before the display needs it, allowing the circuit to be disabled during the blank period without affecting the actual display output

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The high impedance state is applied locally to the output terminal of the gamma reference voltage generation circuit during the vertical blank period. This localized impedance change allows the circuit to conserve power in the voltage generation portion while maintaining the ability to quickly resume normal operation when the vertical active period begins

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11727866B2Power management device and display device including the same

Publication Date: 2023.08.15 LX SEMICON CO LTD

AI summary

The present disclosure relates to a power management device and a display device comprising the same, and more particularly, to a power management device and a display device comprising the same, capable of reducing the power consumption of a display device by disabling a gamma reference voltage generation circuit when the display device is driven at a low scan rate.