Light Emission Control Device Start Circuit Delay
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light emission control devices for projectors face issues with unstable drive signals causing overcurrent when power is turned on, leading to unintended light emission or overheating, and require external sub-constant current sources to mitigate this, increasing the number of external components.
Innovation Solution
A light emission control device with a start control circuit that delays the output of drive signals after power is turned on, using a power source circuit to regulate voltages for control and drive circuits, ensuring stable switching element operation and preventing overcurrent by maintaining the switching elements off during power initialization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power is turned on for the light emission control device, then the drive signal becomes unstable and overcurrent may flow through the light emission element, but adding a sub-constant current source increases the number of external parts
Solution Approach 1:
The patent combines the sub-constant current source functionality directly into the light emission control device by integrating a delay circuit that generates a start control signal. This merges what would have been separate external components (power source circuit, delay circuit, start control signal generator) into a single integrated device, reducing the number of external parts while maintaining the ability to prevent overcurrent during power-on transient periods
Solution Approach 2:
The delay circuit generates a start control signal that delays the drive signal output until after the power source circuit has stabilized the voltage. This preliminary delay action ensures that when the drive signal is finally output, the voltage is stable and overcurrent is prevented, while the integrated design keeps the component count low
2Speed
If the drive signal is output immediately after power is turned on, then the response time is fast, but overcurrent flows through the light emission element causing unintended light emission or overheating
Solution Approach 1:
The start control signal from the delay circuit performs a preliminary action by delaying the drive signal output until the power source circuit has stabilized. This preliminary delay prevents overcurrent conditions while maintaining the fastest possible response time given the voltage stabilization requirement, as the drive signal is output immediately once the delay period expires
Data Source
AI summary
A light emission control device includes a power source circuit for a drive circuit that supplies a power for a drive circuit based on an input power, a power source circuit for a control circuit that supplies a power for a control circuit based on the input power, a control circuit, a drive circuit, and a start control circuit. The control circuit outputs a control signal for controlling turning on/off of a switching element. The drive circuit outputs a drive signal for driving the switching element based on the control signal. The start control circuit outputs a start control signal for delaying a timing at which the output of the drive signal is started after the input power is turned on.