Voltage Supply Unit Current Control for Display Gate Drivers
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Solution Overview
Problem
Display devices face issues with abnormal image display and component damage due to excessive current supply when the gate driver performs abnormal driving operations, even when the display is not powered off, and the voltage supply unit fails to recover to normal current levels after discharge signal recovery.
Innovation Solution
A voltage supply unit with a current control circuit that limits the current flowing to a node to a specific current limit value, using a regulator, resistor, and diodes, to prevent excessive current supply to the gate driver, and includes a discharge control circuit to manage gate signals and timing for normal and discharge modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate driver performs discharge mode operation to prevent afterimage, then data voltages are discharged from pixels, but excessive current is supplied to the gate driver causing component damage
Solution Approach 1:
The current control circuit is configured to limit the current supplied to the gate driver before the excessive current can cause damage. When the discharge signal is activated, the current control circuit preemptively restricts the current flow through the voltage supply unit, preventing the harmful effect of excessive current while still allowing the discharge mode to clear afterimages from the display panel.
2Reliability
If the gate driver continuously operates in discharge mode, then abnormal images are prevented, but the voltage supply unit fails to recover current to normal levels causing continuous abnormal display
Solution Approach 1:
The current control circuit monitors the current supplied to the gate driver and provides feedback control. When the discharge signal is deactivated, the circuit detects the current level and adjusts the voltage supply accordingly, ensuring the current returns to normal operating levels. This feedback mechanism prevents the voltage supply unit from remaining in a high-current state, which would otherwise cause continuous abnormal display.
3Productivity
If the voltage supply unit supplies high current to the gate driver during discharge mode, then the discharge function is effective, but resistors and other components are burnt
Solution Approach 1:
The current control circuit is designed to cushion the current flow before it reaches levels that would damage components. By incorporating current limiting functionality in the voltage supply unit, the circuit preemptively protects resistors and other components from excessive current during discharge mode operation, while still maintaining sufficient current to effectively discharge pixel voltages and prevent afterimages.
Data Source
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Figure 3A~3B
AI summary
A voltage supply unit and a display device including the voltage supply unit are provided. The voltage supply unit includes a first voltage input terminal to which a first voltage as a DC voltage is input; a second voltage input terminal to which a second voltage as an AC voltage is input; a first capacitor between a first node and the second voltage input terminal; and a current control circuit between the first voltage input terminal and the first node and controlling a current value flowing from the first voltage input terminal to the first node so as to be equal to or less than a current limit value.