Adaptive Cascode Reference Voltage Circuit for PVT Stability
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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 mismatches in current generation 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
1Measurement precision
If a reference voltage generator circuit is used to generate a uniform reference voltage, then the accuracy of the reference voltage improves, but the circuit becomes sensitive to temperature variations causing current mismatch
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the bias voltage applied to the cascode transistors based on temperature. The adaptive cascode circuit modifies the voltage parameter to compensate for temperature-induced variations in transistor characteristics, thereby maintaining accurate current matching and reference voltage stability across different temperature conditions.
Solution Approach 2:
The patent implements feedback through the adaptive cascode circuit that monitors temperature conditions and adjusts the bias voltage accordingly. This feedback mechanism allows the circuit to automatically compensate for temperature drift, maintaining the accuracy of the reference voltage generator by correcting current mismatch caused by thermal effects.
2Use of energy by moving object
If the power supply voltage is decreased to reduce power consumption, then energy efficiency improves, but the accuracy of the reference voltage generator circuit deteriorates
Solution Approach 1:
The patent applies dynamics by making the bias voltage adaptive rather than fixed. The adaptive cascode circuit dynamically adjusts the bias voltage based on operating conditions, allowing the reference voltage generator to maintain accuracy across a wide range of power supply voltages. This dynamic adjustment compensates for the reduced voltage headroom in low-power operation, preserving circuit performance while enabling lower power consumption.
3Productivity
If transistors are used in the reference voltage generator circuit, then the circuit can generate reference voltage, but the turn-on voltage of transistors varies with temperature causing current mismatch
Solution Approach 1:
The patent applies parameter changes by adjusting the bias voltage parameter of the cascode transistors in response to temperature variations. This dynamic parameter adjustment compensates for the changing turn-on voltage of the transistors, maintaining stable current matching and ensuring reliable reference voltage generation across different temperature conditions.
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.