Display Output Circuit Shoot-Through Current Suppression
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Solution Overview
Problem
Existing output circuits for driving data lines in display devices face challenges in suppressing shoot-through current while maintaining high-speed operation, leading to increased power consumption and heat generation, and existing solutions either require complex configurations or compromise on current consumption and stability.
Innovation Solution
The proposed output circuit incorporates a differential amplification stage, an output amplification stage, an amplification acceleration circuit, and a capacitance connection control circuit, which includes switches and transistors to manage the connection of capacitive elements to voltage supply terminals, allowing for rapid charging and discharging without increasing the driving current of the differential pair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the driving current of the differential pair is increased to enable high-speed operation, then the operation speed is improved, but the power consumption and heat generation increase
Solution Approach 1:
The patent applies preliminary action by pre-charging the capacitive element to a voltage higher than the power supply voltage before the switching transition. This pre-charged capacitor then discharges through the output transistor during the transition, providing the necessary current spike for high-speed operation without requiring increased differential pair current, thus avoiding increased power consumption and heat generation
Solution Approach 2:
The patent implements periodic action by alternately switching between two states: (1) charging the capacitive element to a voltage higher than the power supply voltage through a dedicated charging circuit, and (2) discharging this pre-charged capacitor through the output transistor during the actual switching transition. This periodic charge-discharge cycle enables high-speed transitions without sustained high current draw that would cause power consumption and heat generation
2Object-generated harmful factors
If a complex circuit configuration is used to suppress shoot-through current, then the shoot-through current is reduced, but the device complexity increases
Solution Approach 1:
The patent extracts the shoot-through current suppression function from the main output circuit by using a separate capacitive element and dedicated charging circuit. The capacitor is connected to the output terminal only during transition periods to suppress shoot-through current, while the main output circuit remains simple. This separation allows shoot-through current suppression without adding complexity to the core output stage
Solution Approach 2:
The patent introduces a capacitive element as an intermediary between the power supply and the output terminal during switching transitions. This capacitor acts as a mediator that provides the necessary current for fast transitions while preventing direct short-circuit current flow between power supply rails. The capacitor charges to a voltage higher than the power supply voltage and then discharges through the output transistor, suppressing shoot-through current without requiring complex control circuitry
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 configuration enables high-speed operation while suppressing shoot-through current and reducing power consumption, achieving efficient data line driving without the need for complex circuitry or increased current values.
Implementation Method 1
a capacitance element having one terminal connected to the output terminal and having the other terminal switchably connected to a voltage supply terminal supplied with a voltage higher than a power supply voltage
Data Source
AI summary
Disclosed is an output circuit including a differential amplifier stage, an output amplifier stage, an amplification acceleration circuit and a capacitance connection control circuit. The output amplifier stage includes push/pull type transistors connected an output terminal. The amplification acceleration circuit includes a first switch and a first transistor, connected between a first output of the differential amplifier stage and the output terminal, and a second transistor and a second switch connected between the output terminal and a second output of the differential amplifier stage. The capacitance connection control circuit includes first capacitive element having first end connected to the output terminal, a first switch connected between a second end of the first capacitive element and a first voltage supply terminal, and a second switch connected between the second end of the first capacitive element and one output of a first differential pair of the differential amplifier stage.