Output Circuit Dynamic Current Control for Pressure Sensor Voltage Range
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Solution Overview
Problem
Conventional output circuits for pressure sensors fail to set the lower clamp voltage close to ground voltage while maintaining the upper clamp voltage close to the power supply voltage, leading to an inefficient voltage range for output signals to engine ECU.
Innovation Solution
An output circuit with a constant current circuit that adjusts the constant current based on the output signal voltage, turning off the current when the voltage decreases to set the lower clamp voltage close to ground and increasing it to set the upper clamp voltage close to the power supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional output circuit uses fixed clamp voltages determined by resistors, then the circuit structure is simple, but the lower clamp voltage cannot be close to ground voltage while maintaining upper clamp voltage close to power supply voltage
Solution Approach 1:
The patent applies dynamics by making the constant current adjustable rather than fixed. The constant current circuit changes its current output dynamically based on the output signal voltage level, allowing the lower clamp voltage to be close to ground when needed and the upper clamp voltage to approach the power supply voltage. This dynamic adjustment resolves the contradiction by enabling precise voltage range control without requiring complex fixed resistor networks for each voltage level.
Solution Approach 2:
The patent changes the parameter of constant current from a fixed value to a variable value that depends on the output signal voltage. By controlling the constant current magnitude based on voltage conditions, the circuit achieves precise clamp voltage positioning (lower near ground, upper near power supply) without the structural complexity of multiple fixed resistor dividers or switching networks.
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 allows for a larger voltage range for the output signal, with the upper clamp voltage being closer to the power supply voltage and the lower clamp voltage closer to ground, enhancing the accuracy and range of the output signal for engine ECU detection.
Implementation Method 1
The output signal is feedback to the constant current circuit. The constant current circuit changes the amount of the constant current in accordance with the voltage of the output signal.
Data Source
AI summary
An output circuit includes a constant current circuit that generates and supplies a constant current to an output terminal of the output circuit. Based on the constant current, the output circuit converts an input signal to an output signal having a voltage within a voltage range specified by upper and lower clamp voltages. The output signal is feedback to the constant current circuit. The constant current circuit changes the amount of the constant current in accordance with the output signal in such a manner that the constant current increases with an increase in the output signal and becomes zero when the output signal decreases to or below a threshold voltage. Thus, the upper clamp voltage is made as close to a power supply voltage as possible and the lower clamp voltage is made as close to a ground voltage as possible.