LED Driver Circuit With Reduced Parasitic Capacitance
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Solution Overview
Problem
Conventional light drivers have large parasitic capacitances due to multiple switch components, leading to prolonged time for light-emitting diodes to reach desired brightness.
Innovation Solution
A driver circuit with a control circuit, reference current source, transistors, and operational amplifier configuration that minimizes switch components between the control terminal and output terminal, allowing rapid adjustment of light-emitting diode current based on brightness information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple switch components are disposed between control terminal and output terminal in conventional light driver, then current control capability is improved, but total parasitic capacitance increases and response time prolongs
Solution Approach 1:
The patent removes unnecessary switch components from the circuit path between the control terminal and output terminal. Specifically, it eliminates switch components that would create parasitic capacitances, retaining only essential components for current control. This extraction of harmful elements reduces total parasitic capacitance and enables faster response time while maintaining necessary current control functionality through alternative control mechanisms.
Solution Approach 2:
The patent introduces a current mirror circuit as an intermediary mechanism to achieve current control without relying on multiple switch components. The current mirror circuit provides precise current control through transistor matching and feedback mechanisms, eliminating the need for additional switches that would increase parasitic capacitance and response time.
2Adaptability or versatility
If multiple switch components are disposed in conventional light driver, then current switching function is enhanced, but parasitic capacitance increases
Solution Approach 1:
The patent extracts and removes switch components that generate parasitic capacitances from the circuit. By eliminating these harmful components while retaining the essential current switching function through a simplified transistor-based control mechanism, the circuit achieves adaptability without the harmful side effects of increased parasitic capacitance.
Solution Approach 2:
The patent changes the control parameter mechanism from multiple switch components to a transistor-based current mirror circuit with feedback control. This parameter change enables current switching functionality to be achieved through continuous control rather than discrete switching, reducing parasitic capacitance while maintaining adaptability.
Data Source
AI summary
A driver circuit for adaptively switching a light-emitting diode current is provided. The driver circuit at least includes a first transistor, a first switching component, a second transistor, a third transistor and an operational amplifier. A first terminal of the first transistor is connected to a first input terminal of the operational amplifier. A first terminal of the first switching component is connected to a control terminal of the first transistor. A control terminal of the second transistor is connected to a second terminal of the first switching component. A first terminal of the third transistor is connected to one or more light-emitting diodes. A second terminal of the third transistor is connected to a first terminal of the second transistor and a second input terminal of the operational amplifier. An output terminal of the operational amplifier is connected to a control terminal of the third transistor.