Reference Voltage Circuit With Stabilized Output Transistor Bias
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Solution Overview
Problem
Conventional reference voltage circuits are susceptible to variations in power supply voltage, leading to unstable operating points in output transistors and difficulty in maintaining a constant reference voltage.
Innovation Solution
A reference voltage circuit design incorporating an output control circuit with a stabilization transistor, where the gate-source voltage of the stabilization transistor is set to be equal to or greater than the drain-source voltage of the output transistor, ensuring a constant drain-source voltage and stable operating point even with power supply variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the drain of the output transistor is directly connected to the power supply terminal, then the circuit structure is simple, but the operating point of the output transistor becomes susceptible to power supply voltage variation
Solution Approach 1:
A stabilization transistor is introduced as an intermediary element between the power supply terminal and the output transistor. This stabilization transistor acts as a buffer that isolates the output transistor from direct power supply voltage variations, thereby maintaining a stable operating point while preserving circuit simplicity
Solution Approach 2:
The invention changes the voltage parameter at the drain of the output transistor by introducing the stabilization transistor. The stabilization transistor maintains a constant voltage difference between its drain and source, which in turn stabilizes the drain voltage of the output transistor against power supply variations
2Adaptability or versatility
If the output transistor operating point varies with power supply voltage, then the circuit responds to power supply changes, but the reference voltage becomes unstable
Solution Approach 1:
The stabilization transistor provides a feedback mechanism where its gate-source voltage automatically adjusts to maintain a constant drain-source voltage. This feedback action compensates for power supply voltage changes, ensuring the reference voltage remains stable while the circuit remains responsive to legitimate operational changes
Data Source
AI summary
Provided is a reference voltage circuit configured to supply a reference voltage in which a variation in voltage with respect to a variation in power supply voltage is suppressed. The reference voltage circuit includes a reference voltage generation circuit which includes an output line for supplying a generated reference voltage to an output terminal; and an output control circuit which includes an output transistor and a stabilization transistor, and is configured to control the supply of the reference voltage to the output terminal, the output transistor containing a gate to which a control voltage is to be provided, the stabilization transistor containing a gate to be connected to a source of the output transistor, and a source to be connected to a drain of the output transistor, and having a gate-source voltage that is equal to or more than a dram-source voltage in a saturation region of the output transistor.