Laser Driver Circuit With Dual FETs For Pulse Width And Peak Current Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing drive circuits for light-emitting elements face challenges in efficiently controlling pulse width and peak current of laser light sources without replacing components or adjusting circuit constants, which affects the stability and accuracy of light output and range finding applications.
Innovation Solution
A lighting module that includes a voltage-current controller, a capacitor, and two field effect transistors (FETs) connected in series to the laser light source, where the first FET controls pulse width and the second FET adjusts resistance value to control the peak current, enabling precise control of light emission and stabilizing light intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single FET is used to control both pulse width and peak current, then device complexity is reduced, but control precision and light output stability deteriorate
Solution Approach 1:
The control function is segmented into two independent FETs: the first FET controls pulse width by switching the current on and off, while the second FET controls peak current by adjusting its resistance value. This segmentation allows each FET to specialize in one control parameter, achieving precise independent control of both pulse width and peak current without increasing overall system complexity.
2Adaptability or versatility
If circuit constants are adjusted to control light output, then component replacement is avoided, but adaptability and real-time adjustment capability deteriorate
Solution Approach 1:
The patent employs two dynamically controllable FETs that can be adjusted in real-time through voltage control. The first FET's gate voltage controls pulse width dynamically, while the second FET's gate voltage adjusts its resistance value to control peak current dynamically. This dynamic control capability allows the circuit to adapt to different operating conditions without requiring physical component replacement or fixed circuit constant adjustments.
3Power
If high-power light output is achieved, then lighting intensity is improved, but heat generation and reliability worsen
Solution Approach 1:
The patent implements a feedback control mechanism where the controller adjusts the gate voltages of both FETs based on the desired light output requirements. The first FET's pulse width modulation and the second FET's resistance control work in coordination to achieve the target power output while preventing excessive current that could generate harmful heat. This feedback-based control ensures the system operates within safe parameters, maintaining reliability even at high power levels.
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 allows for high-speed, high-power light output stabilization, improved range finding accuracy, and real-time adjustment of current to maintain constant light intensity, reducing inductance and parasitic capacitance for faster current changes and enhanced reliability.
Implementation Method 1
The first FET controls a pulse width of a current flowing through the laser light source in accordance with a first voltage value applied to a gate of the first field effect transistor
Implementation Method 2
The second FET changes in resistance value in accordance with a second voltage value applied to a gate of the second field effect transistor, and controls, with the resistance value, a peak value of the current flowing through the laser light source
Implementation Method 3
a capacitor to be charged with power supplied from a voltage-current controller
Data Source
AI summary
A lighting module includes a voltage-current controller to control power externally supplied, a capacitor charged with power supplied from the voltage-current controller, a laser light source to emit laser light driven by a current from the capacitor, first and second FETs electrically connected in series to the laser light source, and circuitry that controls a first voltage value applied to the first FET and a second voltage value applied to the second FET, to control a resistance value of the second FET. The first FET controls a pulse width of the current flowing through the laser light source in accordance with the first voltage value applied to a gate thereof. The second FET changes in resistance value in accordance with the second voltage value applied to a gate thereof and controls, with the resistance value, a peak value of the current flowing through the laser light source.