ECU Oscillation Stop Detection Circuit Power Control
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Solution Overview
Problem
The existing Electronic Control Units (ECUs) with dual microcomputers face a no-monitoring period when the oscillator circuit stops, leading to potential unintended control actions due to power supply instability, as the monitoring unit's power may fall before the microcomputer's, causing abnormal calculations.
Innovation Solution
The ECU incorporates an oscillation stop detection circuit that controls transistors in the power circuits to ensure the monitoring unit remains powered while the microcomputer is shut down, preventing the no-monitoring period by switching the series power source of the monitor power circuit to an ON state and the microcomputer power circuit to an OFF state when the oscillator stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oscillator circuit stops outputting the clock signal, then the microcomputer power circuit and monitor power circuit cannot generate PWM signals and transistors become inoperable, but the monitoring unit's power falls before the microcomputer's power, causing a no-monitoring period
Solution Approach 1:
The patent applies preliminary action by detecting the oscillator stop condition before the power collapse occurs and proactively switching the transistors to appropriate states. The detection circuit identifies the oscillator failure early, allowing the control circuit to switch the fourth transistor to ON and second transistor to OFF before the monitoring unit's power falls, thereby preventing the no-monitoring period from occurring in the first place
Solution Approach 2:
The patent introduces an intermediary detection circuit and control circuit between the oscillator and the power circuits. This intermediary system monitors the oscillator's operation and mediates the power supply state by controlling the transistors, ensuring that the monitoring unit remains powered longer than the microcomputer when oscillator failure occurs, thus preventing the no-monitoring period
2Device complexity
If both microcomputer and monitoring unit share the same oscillator circuit, then device complexity is reduced, but the monitoring unit cannot function when the oscillator stops
Solution Approach 1:
The patent applies dynamics by making the power circuit states changeable and adaptive based on oscillator operation. The control circuit dynamically adjusts the switching states of the transistors in response to oscillator failure, transitioning from a shared-power configuration to a differentiated power state where the monitoring unit remains powered while the microcomputer is shut down, ensuring continuous monitoring capability without adding separate oscillators
3Use of energy by moving object
If the transistor switches off when oscillator stops, then power consumption is reduced, but the output voltage falls causing abnormal microcomputer operation
Solution Approach 1:
The patent converts the harmful effect of voltage fall during oscillator stop into a beneficial outcome. By detecting the oscillator failure and proactively switching the fourth transistor to ON and second transistor to OFF, the system uses the power collapse event to its advantage: the monitoring unit's power is maintained through the fourth transistor while the microcomputer is cleanly shut down via the second transistor, transforming what would be an abnormal operation condition into a controlled state transition that prevents unintended control actions
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 ensures that the monitoring unit continues to function even after the microcomputer has stopped, preventing unintended control actions and maintaining system stability by prioritizing power supply to the monitoring unit during oscillator failures.
Implementation Method 1
an oscillation stop detection circuit that detects a stop of a clock output from the oscillator
Implementation Method 2
a switching power source having a first transistor that switchingly operates on a clock-generated signal and that lowers a voltage from an external power source
Implementation Method 3
a series power source having a second transistor that lowers an output voltage of the switching power source and that supplies the output voltage to the microcomputer
Data Source
AI summary
An electronic control unit includes a microcomputer, a monitoring unit, a clock-generating oscillator circuit, a first power circuit supplying power to the microcomputer, and a second power circuit supplying power to the monitor microcomputer. The first power circuit includes a first switching power source including a first transistor and a first series power source including a second transistor. The second power circuit includes a second switching power source including a third transistor and a second series power source including a fourth transistor. Further, the ECU includes a power control circuit controlling each of the transistors and an oscillation stop detection circuit. When a stop of oscillation is detected, the power control circuit switches ON the second transistor, and switches OFF the fourth transistor, thereby diminishing a no-monitoring period of the microcontroller during a stop of the clock output.