Sensor Output Circuit With Constant Current for ECU Fault Detection
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Solution Overview
Problem
Conventional physical quantity outputting circuits face challenges in detecting abnormal connections between the circuit and an external engine controlling unit, leading to fluctuations in internal power supply voltage and current consumption, which affect the accuracy and reliability of signal output.
Innovation Solution
The proposed solution involves a physical quantity outputting circuit with specific resistor configurations and a current consumption adjusting circuit, which maintains a constant current flow and internal power supply voltage by setting resistance values of the first and second resistors relative to the pull-down or pull-up resistors in the ECU, ensuring that the internal power supply voltage remains stable despite fluctuations in the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional physical quantity outputting circuits are used without specific resistor configurations, then the circuit can operate with simple design, but the internal power supply voltage fluctuates and current consumption varies, affecting output signal accuracy
Solution Approach 1:
The patent applies parameter changes by carefully selecting and setting the resistance values of the first and second resistors relative to the pull-down or pull-up resistors in the ECU. This parameter optimization ensures that the current through the output terminal remains substantially constant, which stabilizes the internal power supply voltage and eliminates the need for complex additional circuitry, thus improving measurement precision while maintaining relatively simple device complexity
Solution Approach 2:
The patent implements a feedback mechanism where the output voltage fluctuation is compensated by the resistor network configuration. When the output voltage changes, the constant current condition maintained by the resistor ratios automatically adjusts the internal power supply voltage to remain stable, providing inherent feedback stabilization without requiring external control circuits
2Reliability
If the circuit uses simple resistor configuration, then the device complexity is low, but the current consumption fluctuates during abnormal connections, reducing reliability
Solution Approach 1:
The patent uses parameter changes by setting specific resistance value ratios between the first and second resistors and the ECU's pull-down or pull-up resistors. This ensures that during abnormal connections (such as short circuits or disconnections), the current consumption remains substantially constant, providing reliable abnormal connection detection while keeping the circuit structure simple without additional complex components
Solution Approach 2:
The circuit implements self-service by using the existing pull-down or pull-up resistors in the ECU as part of the current stabilization mechanism. The resistor network automatically maintains constant current consumption during abnormal conditions without requiring external monitoring circuits or additional active components, making the system self-diagnosing and reliable
3Stability of the object's composition
If no current consumption adjustment mechanism is implemented, then the circuit design remains simple, but the internal power supply voltage fluctuates with output voltage changes, affecting linearity
Solution Approach 1:
The patent applies parameter changes by optimizing the resistance values of the first and second resistors to specific ratios relative to the ECU's internal resistors. This parameter selection ensures that the current through the output terminal remains substantially constant regardless of output voltage fluctuations, thereby stabilizing the internal power supply voltage and improving linearity without adding complex voltage regulation circuits
Solution Approach 2:
The resistor network acts as an intermediary element between the power supply and the output amplifier. By carefully selecting the resistor values, this intermediary network maintains constant current flow and stabilizes the internal power supply voltage, mediating the relationship between output voltage fluctuations and power supply stability without requiring active voltage regulation components
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 effectively prevents fluctuations in internal power supply voltage and maintains constant current consumption, enhancing the linearity and reliability of the output signal, even during abnormal connections, thereby improving the sensing of abnormal connections and reducing current consumption.
Implementation Method 1
a first resistor 50 and a second resistor 52 different from those of the conventional art. By setting the resistance value of the first resistor 50 and the resistance value of the second resistor 52, it is possible to maintain a state in which a current having substantially the same value flows
Data Source
AI summary
Provided is a physical quantity outputting circuit including a first output terminal, a power supply terminal to which an external power supply voltage is input, a reference terminal to which a reference voltage is input, a power supply voltage circuit which generates an internal power supply voltage from the external power supply voltage, a first output amplifier to which a first input signal corresponding to the physical quantity sensing result is input and which outputs the first output voltage corresponding to the first input signal to the first output terminal, a first resistor connected between the power supply terminal and the first output terminal, and a second resistor connected between the first output terminal and the reference terminal. In the physical quantity outputting circuit, current that flows from the power supply voltage circuit to the first output amplifier has a constant value.