Temperature-Compensated Reference Circuit With Low-Power FET Biasing
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Solution Overview
Problem
Existing reference circuits face challenges in providing stable voltage and current under temperature variations while minimizing power consumption and circuit area, with previous solutions either consuming excessive power or introducing noise interferences due to the use of bipolar junction transistors and large resistors.
Innovation Solution
A reference circuit with temperature compensation is designed using a bias generation circuit and a current output circuit, employing field effect transistors to generate reference voltages and currents with adjustable temperature characteristics, allowing for separate adjustment of compensated voltage and current, and utilizing a voltage output circuit with field effect transistors to operate in the saturation region for effective temperature compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bipolar junction transistors are used in the differential voltage reference circuit, then temperature compensation can be achieved, but power consumption increases
Solution Approach 1:
The patent changes the device type parameter from bipolar junction transistors to field effect transistors, maintaining the temperature compensation function while significantly reducing power consumption. The field effect transistors operate in saturation region to generate reference currents with opposite temperature coefficients that compensate for each other.
Solution Approach 2:
The patent creates a copy of the temperature compensation mechanism using field effect transistors that mimics the functionality of bipolar junction transistors. Two sets of field effect transistors generate currents with opposite temperature characteristics, copying the compensation effect achieved by bipolar devices but with lower power consumption.
2Reliability
If an operational amplifier is used in the positive temperature coefficient correction circuit, then temperature compensation can be achieved, but circuit area increases
Solution Approach 1:
The patent extracts and removes the operational amplifier from the circuit, replacing it with a simpler field effect transistor-based configuration. This eliminates the need for the large-area operational amplifier while maintaining the temperature compensation function through the field effect transistor current mirrors and resistors.
Solution Approach 2:
The patent replaces the expensive and large-area operational amplifier with cheaper, smaller field effect transistors and resistors. The field effect transistor-based compensation circuit achieves the same temperature stability function with significantly reduced circuit area and lower component cost.
3Reliability
If a large resistor is directly connected between output voltage and ground, then higher compensated voltage can be output, but circuit area and power consumption increase
Solution Approach 1:
The patent changes the resistor value parameter to a smaller range, using field effect transistors in saturation region to provide the necessary current control. The field effect transistors replace the function of large resistors, enabling voltage output without requiring large resistance values that would increase area and power consumption.
Solution Approach 2:
The patent substitutes the passive resistor-based voltage control mechanism with an active field effect transistor-based control system. The field effect transistors, operating in saturation region, provide dynamic current control that replaces the static function of large resistors, achieving better performance with smaller area and lower power consumption.
4Reliability
If a large resistor is directly connected between output voltage and ground, then higher compensated voltage can be output, but noise interference increases
Solution Approach 1:
The patent substitutes the passive resistor-based voltage generation with an active field effect transistor-based system. The field effect transistors, operating in saturation region, provide low-noise current control that replaces the noisy large resistor configuration, achieving high output voltage without the associated noise interference.
Solution Approach 2:
The patent creates a noise-free copy of the voltage reference function using field effect transistors. Instead of using large resistors that generate thermal noise, the field effect transistor current mirrors replicate the reference voltage function with significantly lower noise levels, maintaining voltage stability without the harmful noise side effects.
Data Source
AI summary
The present invention discloses a reference circuit with temperature compensation, which is characterized in that a current output circuit is designed to receive a reference voltage from a bias voltage generation circuit, generate two reference currents with opposite temperature variation characteristics, and then merge them into a compensated current with temperature compensation. In addition, a voltage output circuit is designed to receive a reference voltage from a bias voltage generation circuit, which includes several field-effect transistors operating in saturation regions, and a precision voltage increases with threshold voltages of the field-effect transistors to compensate for the temperature variation. Resistors can be incorporated or sizes of the field effect transistors can be changed to adjust the output current, output voltage or the temperature variation characteristics.