Bias Generator Temperature Compensation Circuit
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Solution Overview
Problem
Conventional bias generators for single-ended low noise amplifiers experience variations in drain-to-source voltage with temperature, affecting the gain and reliability of the amplifier due to the temperature dependence of bias voltages.
Innovation Solution
A bias generator is designed with a first switch and a second switch, generating a reference voltage and two bias voltages, where the second bias voltage is based on the reference voltage, and a current mirror circuit with zero-temperature coefficient current sources to maintain a constant voltage across the first switch, independent of temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional bias generators are used with single-ended low noise amplifiers, then the amplifier can operate with standard biasing circuits, but the drain-to-source voltage of the input transistor varies with temperature affecting gain and reliability
Solution Approach 1:
The patent changes the parameter of bias voltage generation by introducing a temperature compensation mechanism. The bias generator uses a bandgap reference voltage and temperature-dependent current sources to adjust the bias voltages in a way that compensates for temperature variations, thereby maintaining stable drain-to-source voltage and gain across temperature ranges.
Solution Approach 2:
The patent introduces an intermediary temperature compensation circuit that mediates between the temperature variations and the bias voltages. This intermediary circuit uses temperature-dependent current sources and resistors to generate compensating signals that stabilize the bias conditions, preventing temperature from directly affecting the amplifier gain.
2Reliability
If temperature-independent bias voltages are implemented, then gain stability over temperature is improved, but device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by designing a bias generator that simultaneously provides temperature compensation and standard biasing functions. The same circuit structure generates both the compensation signals and the actual bias voltages for the amplifier, reducing the need for separate compensation circuits and minimizing overall device complexity.
Solution Approach 2:
The patent merges the temperature compensation function with the bias generation function into a single integrated circuit. The bias generator combines temperature-dependent current sources, bandgap reference, and voltage division networks to simultaneously accomplish temperature sensing, compensation signal generation, and bias voltage output, thereby reducing component count and circuit complexity.
Data Source
AI summary
A bias generator and a method for generating a bias voltage are presented. The bias generator is for use with an electronic circuit comprising a first switch coupled in series with a second switch. The bias generator is adapted to generate a reference voltage, a first bias voltage, and a second bias voltage. The second bias voltage is based on the reference voltage. After applying the first voltage to the first switch and the second voltage to the second switch, the bias generator controls a voltage across the first switch. The bias generator may be adapted to set a value of the reference voltage to control the voltage across the first switch. For instance, the reference voltage may be set to a fix value so that the voltage across the first switch is maintained at a constant value.