Vehicle Microcomputer Power Supply Interruption for Sensor Accuracy
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Solution Overview
Problem
The high power consumption of vehicle-installed microcomputer systems, especially when in sleep mode, due to the large power supply capacity needed to support multiple onboard sensors, leads to rapid battery exhaustion, despite efforts to reduce consumption by entering a sleep mode with low clock frequency operations.
Innovation Solution
A dual power supply circuit system where a high-accuracy power supply circuit is only active during regular mode and is disconnected during sleep mode, reducing power consumption by saving energy on the high-accuracy power supply and sensor circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-accuracy constant-voltage power supply circuit is used to supply power to the microcomputer system, then the control accuracy is maintained, but the power consumption increases significantly
Solution Approach 1:
The power supply system dynamically switches between high-accuracy and low-power modes based on operational requirements. During sleep mode, the high-accuracy power supply circuit is disconnected and replaced with a low-power alternative, while during active operation, the high-accuracy circuit is reconnected to ensure proper control functionality.
Solution Approach 2:
The power supply system is divided into two separate power supply circuits: a high-accuracy constant-voltage power supply circuit for active operation and a low-power power supply circuit for sleep mode. This segmentation allows each circuit to be optimized for its specific function without compromise.
2Use of energy by moving object
If the microcomputer enters sleep mode with low clock frequency to reduce power consumption, then energy usage decreases, but the system cannot perform essential arithmetic computations
Solution Approach 1:
The system periodically transitions between sleep mode and awake mode. During sleep mode, power consumption is minimized. When an awake signal is received or a predetermined time elapses, the system temporarily wakes up to perform essential operations, then returns to sleep mode. This periodic activation allows the system to balance power savings with necessary computational tasks.
3Stability of the object's composition
If the high-accuracy power supply circuit remains active during sleep mode to maintain voltage stability, then power supply accuracy is preserved, but the vehicle battery exhausts too soon
Solution Approach 1:
The high-accuracy power supply circuit is extracted from the active power supply configuration during sleep mode and replaced with a low-power power supply circuit. This extraction eliminates the excessive power consumption of the high-accuracy circuit when its precision is not needed, thereby extending battery life while maintaining sufficient voltage stability through the low-power circuit.
Data Source
AI summary
The vehicle-installed microcomputer system includes an A/D converter converting analog signal sent from an onboard sensor circuit into digital signal, a microcomputer which operates in one of regular mode where a predetermined arithmetic computation on the digital signal is performed, and sleep mode where the predetermined arithmetic computation is prohibited from being performed, a first power supply circuit supplied with electric power from outside to produce a power supply voltage to be applied to the microcomputer, a second power supply circuit supplied with electric power from outside through an interruption switch to produce a power supply voltage to be applied to the A/D converter and the sensor circuit, the second power supply circuit having an output voltage accuracy higher than that of the first power supply circuit. The power interruption switch is opened to prohibit the second power supply circuit from being supplied with electric power in the sleep mode.