Electric Current Control Circuit for Display Devices
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Solution Overview
Problem
Existing electric current control circuits for light emitting elements face performance improvement demands, particularly in accurately controlling the electric current to achieve high-definition image display and fine gradation expression.
Innovation Solution
The proposed electric current control circuit includes an amplifier with inputters and an outputter, resistance elements, switches, and transistors, which are configured to accurately control the electric current supplied to light emitting elements by adjusting the resistance values and switching states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an analog switch is used to switch externally-attached resistors to change reference electric current magnitude, then the circuit structure is simple, but the performance and precision of electric current control are insufficient
Solution Approach 1:
The patent changes the resistance parameter dynamically by using transistors as variable resistors controlled by the amplifier output. The transistor gate voltage, controlled by the output terminal, adjusts the channel resistance to precisely control the reference current magnitude, enabling continuous parameter adjustment rather than discrete switching
Solution Approach 2:
The patent replaces mechanical analog switches with electronic transistor-based variable resistance control. Instead of mechanically switching between fixed resistors, the system uses transistor channel resistance modulated by voltage to achieve continuous, precise current control without mechanical moving parts
2Measurement precision
If multiple resistance elements and switches are used to improve electric current control precision, then the control precision is improved, but the chip area increases
Solution Approach 1:
The transistor serves multiple functions: it acts as a variable resistor for current control, is controlled by the amplifier output, and integrates the resistance adjustment function within the chip. This multi-functionality eliminates the need for separate switches and external resistors, reducing chip area while maintaining precision
Solution Approach 2:
The patent nests the resistance control function within the transistor structure itself. The variable resistance is created by the transistor channel, which is controlled by the gate voltage from the amplifier output. This nested arrangement integrates multiple functions (amplification, switching, and resistance control) into a compact structure
3Measurement precision
If high precision electric current control is implemented, then image display quality is improved, but power consumption increases
Solution Approach 1:
The amplifier output automatically controls the transistor gate voltage to maintain the desired reference current. The system self-regulates by using the output signal to control the transistor, creating a feedback mechanism that achieves precise current control without requiring additional power-hungry control circuits
Solution Approach 2:
The patent uses voltage parameter changes at the transistor gate to control the channel resistance and thus the reference current. This voltage-based control method is more power-efficient than current-based switching methods, as it uses small voltage signals to modulate the large current through the transistor channel
Data Source
AI summary
An electric current control circuit according to an embodiment of the present disclosure includes: an amplifier including a first inputter, a second inputter, and an outputter; a first resistance element and a second resistance element; a first switch provided between the first resistance element and the second inputter; a second switch provided between the second resistance element and the second inputter; a third switch and a fourth switch electrically coupled to the outputter; a first transistor provided between the first resistance element and a first terminal, the first transistor being to be inputted with an output voltage of the outputter via the third switch; and a second transistor provided between the second resistance element and the first terminal, the second transistor being to be inputted with an output voltage of the outputter via the fourth switch.