Sensor Device Regulator Circuit for Low Voltage Operation
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Solution Overview
Problem
In-vehicle sensor devices face challenges in reducing the drive voltage of signal processing circuits to prevent heat generation while maintaining signal output within the range of the power voltage supplied by the control device, especially with the application of microfabrication processes.
Innovation Solution
The sensor device employs a regulator to generate a voltage lower than the power voltage for the signal processing circuit, using an open collector type operational amplifier and resistance elements to divide and amplify the output voltage, ensuring the output ranges from 0 V to the power voltage, and incorporates Zener diodes and resistance type physical quantity detection elements to improve noise immunity and ratiometric characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the drive voltage of the signal processing circuit is reduced to prevent heat generation, then the circuit can be operated at lower voltage (improving thermal performance), but the output signal amplitude cannot reach the required range up to the power voltage supplied from the control device
Solution Approach 1:
The patent introduces a regulator circuit as an intermediary component between the power voltage supply and the signal processing circuit. The regulator converts the higher power voltage (e.g., 5V or 12V) to a lower operating voltage (e.g., 3.3V or 1.8V) suitable for the microfabricated signal processing circuit, while maintaining the circuit's ability to output signals across the full required voltage range through subsequent amplification stages.
Solution Approach 2:
The patent changes the voltage parameter through multiple stages: first reducing the power voltage from the control device to a lower level for the signal processing circuit via a regulator, then amplifying the output signal back to the required voltage range. This parameter transformation allows the circuit to operate at low voltage while maintaining high output signal amplitude capability.
2Reliability
If a microfabrication process is applied to the signal processing circuit to improve performance, then the circuit achieves higher performance, but the drive voltage must be reduced which creates difficulty in maintaining output within the required voltage range
Solution Approach 1:
The regulator circuit serves as a mediator that decouples the microfabricated signal processing circuit from the control device's power voltage supply. This intermediary allows the circuit to be manufactured with microfabrication processes requiring specific low voltages while still being compatible with standard control device power supplies.
3Power
If the power voltage from the control device is used directly without change, then the circuit can operate with sufficient voltage, but heat generation increases and microfabrication process benefits are reduced
Solution Approach 1:
The regulator circuit changes the voltage parameter from the higher power voltage to a lower operating voltage for the signal processing circuit. This parameter change reduces the power consumption and heat generation of the circuit while maintaining adequate operating voltage through subsequent signal amplification.
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 solution allows for the miniaturization and high-performance operation of the sensor device with reduced noise interference, enabling complex functions in a small area and improving measurement accuracy while maintaining output within the required voltage range.
Implementation Method 1
a regulator 3 in which a power voltage supplied via the power source terminal 7 is received and a voltage lower than the power voltage is generated
Implementation Method 2
an operational amplifier 4 that is operated with the low voltage supplied from the regulator 3 and amplifies the sensor output voltage
Implementation Method 3
resistance elements 5 and 6 constituting a voltage divider that divides the voltage of the sensor output terminal 8
Implementation Method 4
incorporates Zener diodes and resistance type physical quantity detection elements to improve noise immunity
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
In a sensor device 1 according to the present invention, power is supplied from a control device 10 to a power supply terminal 7 and a ground terminal 9 of the sensor device 1 via a power supply line Vcc and a ground line Gnd, respectively, and a sensor output voltage is sent from a sensor output terminal 8 to the control device 10 via a sensor output line Vout. The control device 10 has disposed therein a constant voltage source 11 that supplies a constant voltage to the sensor device 1, and a pull-up resistor 12 connected between the sensor output line Vout and the constant voltage source 11. The sensor device 1 comprises: a physical quantity detection unit 2 that varies a voltage Vsen in accordance with a measured physical quantity; a regulator 3 that generates a low voltage from a power supply voltage supplied from the power supply terminal 7; an open-collector operational amplifier 4 that operates with the low voltage supplied from the regulator 3 to control a voltage for the sensor output terminal 8; and resistor elements 5, 6 that together form a voltage divider circuit for subjecting the voltage for the sensor output terminal 8 to voltage division.