Reference Voltage Generator With Adaptive Cascode PVT Compensation
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Solution Overview
Problem
Reference voltage generator circuits in electronic devices face accuracy issues due to variations in process, voltage, and temperature, leading to mismatched currents and potential abnormal device operation.
Innovation Solution
An electronic device incorporating a reference voltage generator circuit with an adaptive cascode circuit that generates a bias voltage to compensate for temperature changes, ensuring the reference voltage remains uniform by adjusting the emitter-base voltage of transistors, thereby maintaining accuracy across PVT variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reference voltage generator circuit is used to generate a uniform reference voltage, then the performance of other components is improved, but the accuracy decreases due to PVT variations and temperature changes
Solution Approach 1:
The adaptive cascode circuit dynamically adjusts the bias voltage applied to the gate of the first transistor based on temperature variations. By changing the bias voltage parameter, the circuit compensates for temperature-induced shifts in transistor turn-on voltage, thereby maintaining current matching accuracy and reference voltage precision across different temperature conditions.
Solution Approach 2:
The adaptive cascode circuit implements a feedback mechanism where the bias voltage is adjusted based on the temperature condition. The circuit monitors temperature changes and automatically modifies the bias voltage to compensate for their effect on transistor characteristics, ensuring that the reference voltage maintains its accuracy despite environmental variations.
2Device complexity
If the turn-on voltage of transistors varies with temperature, then the reference voltage generator circuit becomes simpler, but current mismatch occurs decreasing accuracy
Solution Approach 1:
The adaptive cascode circuit changes the bias voltage parameter in response to temperature variations. This dynamic parameter adjustment compensates for temperature-induced changes in transistor turn-on voltage, maintaining current matching accuracy without requiring complex circuit topologies or additional temperature sensing components.
3Use of energy by moving object
If power supply voltage is decreased to reduce power consumption, then energy efficiency is improved, but reference voltage accuracy deteriorates
Solution Approach 1:
The adaptive cascode circuit adjusts the bias voltage parameter to compensate for the reduced power supply voltage. By optimizing the bias conditions, the circuit maintains proper transistor operation and current matching even at lower power supply voltages, thereby preserving reference voltage accuracy while enabling reduced power consumption operation.
Data Source
AI summary
An electronic device including: a reference voltage generator circuit to generate a reference voltage based on a first and second voltage, the reference voltage generator circuit including: a first current source to supply a first current to each of a first and second node; an amplifier to amplify a difference between the first voltage of the first node and the second voltage of the second node and to output a difference voltage corresponding to the amplified difference; a first bipolar junction transistor (BJT) connected to the first node; a first resistor connected to the second node; a second BJT connected between the first resistor and ground; a second resistor connected between the second node and ground; and a first transistor to be supplied with a second current from the first current source; and an adaptive cascode circuit to generate a bias voltage applied to a gate of the first transistor.