Channel Buffer Block Bias Voltage Control for High Slew Rate
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Solution Overview
Problem
Display driver circuits with high slew rates consume significant power, leading to increased standby current, which is a challenge for low-power, high-resolution portable displays like smartphones and tablets, as they require both high slew rate and low power consumption.
Innovation Solution
A method of operating a channel buffer block that adjusts bias voltages using coupling capacitors during slewing intervals, increasing bias currents to achieve a high slew rate without increasing standby current, by employing a column driver IC with differential amplifiers and coupling capacitors controlled by control voltages and a pulse width control circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the slew rate of a display driver circuit is increased, then the charging speed of pixels is improved, but the standby current increases
Solution Approach 1:
The patent applies periodic action by using a coupling capacitor to periodically transfer a coupling pulse signal to the bias line during specific intervals (slewing interval and non-slewing interval). This periodic charging and discharging of the coupling capacitor enables dynamic adjustment of bias voltage without requiring continuous high current, thus achieving high slew rate during active periods while maintaining low standby current during non-active periods
Solution Approach 2:
The patent implements dynamics by making the bias voltage adjustable through the coupling capacitor mechanism. The bias voltage dynamically changes based on the coupling pulse signal, allowing the circuit to adapt its operating characteristics. This dynamic adjustment enables the circuit to achieve high slew rate when needed while returning to low-power state when not needed, resolving the contradiction between speed and energy consumption
2Manufacturing precision
If the resolution of a display is increased, then the display quality is improved, but the charging time for pixels is decreased
Solution Approach 1:
The patent applies parameter changes by modifying the bias voltage parameter through the coupling capacitor mechanism. By changing the bias voltage during the slewing interval, the circuit achieves higher output current capability, which compensates for the reduced charging time caused by higher resolution. This parameter adjustment allows the display driver to maintain adequate charging time even when driving high-resolution displays
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 allows for a high slew rate output voltage without increasing standby current, thereby reducing power consumption in portable electronic devices, enabling efficient operation of high-resolution displays.
Implementation Method 1
changing bias voltages applied to bias lines in an input stage included in the channel buffer block using a coupling effect of coupling capacitors during a slewing interval
Data Source
AI summary
A method of operating a channel buffer block is provided. The method includes changing bias voltages applied to bias lines in an input stage included in the channel buffer block using a coupling effect of coupling capacitors during a slewing interval and increasing bias currents in the input stage using input voltages and changed bias voltages.