MOSFET Ignition Sense Circuit for Compact ECU Power Latching
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Solution Overview
Problem
Existing ignition sense and control circuits in vehicle and off-road vehicle ECUs are costly and occupy significant PCB space due to the use of logic gates, operational amplifier ICs, and reference signal/power ICs, necessitating a redesign for cost and space-constrained applications.
Innovation Solution
A low-cost compact ignition sense and control circuit utilizing MOSFETs to control the ON/OFF state of the ECU's main internal power supply or microprocessor, powered by the vehicle's battery supply line, replacing the need for logic gates and reference ICs, and incorporating capacitors, resistors, and diodes for efficient power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If logic gates, operational amplifier ICs, and reference signal/power ICs are used in the ignition sense and control circuit, then the circuit can reliably control the ECU's power supply state, but the circuit occupies significant PCB space and increases manufacturing cost
Solution Approach 1:
The patent combines multiple discrete components (logic gates, operational amplifier ICs, reference signal ICs, reference power ICs) into a single integrated ignition sense and control circuit. This merging of functions into one compact circuit block reduces the overall PCB space required while maintaining the necessary control capabilities for the ECU power supply state.
Solution Approach 2:
The ignition sense and control circuit is designed to perform multiple functions within a single integrated structure: sensing the ignition signal, comparing voltage levels, controlling power supply switching, and providing reference signals. This multi-functionality eliminates the need for separate discrete components, thereby reducing PCB space occupation.
2Reliability
If logic gates, operational amplifier ICs, and reference signal/power ICs are used in the ignition sense and control circuit, then the circuit can reliably control the ECU's power supply state, but the manufacturing cost increases
Solution Approach 1:
The patent integrates multiple discrete components (logic gates, operational amplifier ICs, reference signal ICs, reference power ICs) into a single integrated ignition sense and control circuit. This merging reduces the total component count, which directly lowers manufacturing costs by reducing assembly steps, inventory requirements, and potential failure points.
Solution Approach 2:
The patent extracts and eliminates unnecessary discrete components from the traditional circuit design. By removing redundant logic gates, separate operational amplifier ICs, and reference signal/power ICs, the design reduces component procurement costs and assembly complexity, thereby improving ease of manufacture.
3Productivity
If a compact ignition sense and control circuit is designed to reduce PCB space and cost, then manufacturing efficiency improves, but circuit complexity may increase
Solution Approach 1:
The integrated ignition sense and control circuit is designed with modular internal architecture, dividing complex functions into distinct functional blocks within the single circuit. This segmentation allows for easier manufacturing and testing while maintaining compact form factor, thus improving productivity without excessively increasing overall device complexity.
Data Source
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AI summary
A low-cost compact ignition sense and control circuit is powered by a battery supply line of a vehicle and receives an ignition input signal indicating the turning ON/OFF of a vehicle. Responsive to the ignition input signal, the ignition sense and control circuit utilizes first and second MOSFETS to control an ON/OFF state of a main internal power supply of an ECU or to control an activate/ deactivate state of a microprocessor of the ECU. When the MOSFETS are ON, voltage from the battery supply line is used to either latch the main internal power supply of the ECU to an ON state or to latch the microprocessor of the ECU into an ON state. An OFF signal at the ignition input signal releases the latch to provide a shutdown of the main internal power supply or microprocessor.