Output Buffer Slew Boost Circuit for High-Speed Low-Power Driving
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display devices face challenges in driving output buffers at high speeds while minimizing power consumption, as existing solutions fail to effectively increase the slew rate of output voltage and reduce power consumption simultaneously.
Innovation Solution
The proposed output buffer includes an input stage, current summing stage, output stage, and slew boost circuit, which monitor voltage differences to adjust currents and control voltages, enabling high-speed operation and power reduction by selectively performing slew boost operations and blocking unnecessary currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the slew rate of output voltage is increased to enable high-speed operation, then the driving speed is improved, but the power consumption increases
Solution Approach 1:
The patent implements dynamic current adjustment by monitoring the voltage difference between input and output terminals. When the voltage difference exceeds a threshold, the slew boost circuit activates to increase the current flowing through the output transistor, thereby increasing the slew rate. When the voltage difference is within the threshold, the circuit operates in normal mode with lower current consumption. This dynamic adaptation allows the circuit to optimize between speed and power consumption based on real-time operating conditions.
Solution Approach 2:
The patent changes the operating parameters (current magnitude) of the output stage based on the voltage difference condition. By adjusting the current parameter dynamically - using higher current when voltage difference is large (needing fast response) and lower current when voltage difference is small (normal operation) - the circuit achieves variable slew rate control that resolves the contradiction between speed and power consumption.
2Use of energy by moving object
If normal current is provided to the output stage, then power consumption is reduced, but the slew rate and driving speed decrease
Solution Approach 1:
The circuit dynamically switches between two operating modes: normal mode with lower current for power efficiency, and slew boost mode with higher current for fast response. The transition between modes is controlled by the voltage difference monitor, which detects when the output voltage lags behind the input voltage by more than a threshold amount, indicating the need for enhanced driving capability.
Solution Approach 2:
The slew boost circuit is prepared in advance and can be rapidly activated when needed. By having the boost circuit ready and only activating it when the voltage difference threshold is exceeded, the system maintains low power consumption during normal operation while being capable of immediate high-speed response when required, preventing the need for continuously high current operation.
Data Source
AI summary
This disclosure relates to an output buffer including an input stage configured to monitor a difference between an input voltage and an output voltage, a current summing stage configured to generate amplified currents and control voltages according to the difference between the input voltage and the output voltage monitored by the input stage, an output stage configured to perform a pull-up operation or a pull-down operation according to the control voltages output from the current summing stage to generate the output voltage at an output terminal, and a slew boost circuit configured to perform a slew boost operation of adjusting some currents among currents provided from the current summing stage to the input stage according to the difference between the input voltage and the output voltage by monitoring the difference between the input voltage and the output voltage and selectively perform the slew boost operation by monitoring the control voltages.