Display Driver IC Pre-Charge Controller for AOD Power Reduction
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Solution Overview
Problem
Display driver integrated circuits (DDIs) face increased power consumption and size issues due to the need for large switches in negative charge pumps to support always-on display (AOD) modes, leading to inefficiencies in power management and increased transmission losses.
Innovation Solution
The implementation of a level shifter unit and voltage generator with a pre-charge controller that converts control signals into switch control signals, utilizing a capacitor and switch to generate voltages efficiently, and a buffer to selectively output signals based on pre-charge control, reducing power consumption by optimizing voltage transitions and switching operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of switch in negative charge pump is increased to withstand AOD mode load, then the capability to support AOD mode is improved, but power consumption increases
Solution Approach 1:
The pre-charge controller applies preliminary action by pre-charging the output node to a voltage between the first and second voltages before the switch control signal transitions. This preliminary voltage preparation reduces the voltage differential that the switch must handle during switching, thereby reducing switching losses while maintaining the ability to support AOD mode loads.
Solution Approach 2:
The invention changes the voltage parameter of the output node dynamically by introducing a pre-charge voltage that is higher than the first voltage and lower than the second voltage. This intermediate voltage state reduces the stress on the switch during transitions, lowering power consumption while preserving the switch's capability to handle AOD mode requirements.
2Reliability
If the size of switch in charge pump is increased, then the load handling capability is improved, but switching loss increases
Solution Approach 1:
The pre-charge controller performs preliminary action by setting the output node voltage to an intermediate level before the main switching operation. This reduces the voltage swing that the large switch must accommodate, thereby reducing switching losses while maintaining the load handling capability enabled by the larger switch size.
Solution Approach 2:
The pre-charge voltage acts as an intermediary state between the first and second voltages. This intermediate voltage level reduces the stress on the large switch during transitions, minimizing switching losses while preserving the switch's enhanced load handling capability.
3Reliability
If more switches are used in voltage generator, then the voltage generation capability is improved, but power consumption increases
Solution Approach 1:
The pre-charge controller applies preliminary action by pre-charging the output node before switching operations. This reduces the voltage differential that multiple switches must handle, thereby reducing the cumulative switching losses across all switches while maintaining the voltage generation capability provided by the multiple-switch configuration.
Solution Approach 2:
The invention changes the voltage parameter of the output node by introducing an intermediate pre-charge voltage level. This parameter change reduces the stress on each individual switch and the cumulative stress on the switch network, lowering overall power consumption while preserving the enhanced voltage generation capability.
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 solution reduces power consumption by half, alleviating the burden of increased switch numbers in voltage generators and achieving low power consumption in DDI designs, thereby enhancing the efficiency of AOD mode operations.
Implementation Method 1
a voltage generator including a capacitor and a switch that is turned on or off based on or in response to the switch control signal and configured to generate at least one third voltage
Data Source
AI summary
A display driver integrated circuit (DDI) includes a level shifter unit configured to convert a level of a control signal to a voltage in a range that equal to or greater than a first voltage and is equal to or less than a second voltage and output a switch control signal, and a voltage generator including a capacitor and a switch that is turned on or off based on or in response to the switch control signal and configured to generate at least one third voltage.