Reference Voltage Circuit for Cascode MOS Withstand Limits
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Solution Overview
Problem
Existing solutions for generating a reference voltage for cascode structures in integrated circuits face challenges such as voltage variations, temperature instability, and compatibility with MOS transistors' voltage withstand limits, leading to performance degradation and inefficiencies.
Innovation Solution
A circuit comprising a first voltage divider bridge, MOS transistors, and buffer circuits is designed to generate reference voltages that adapt to supply voltage variations, ensuring transistors operate within safe voltage limits and maintaining performance across different operating modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional circuits are used to generate a DC reference voltage from a supply voltage, then the reference voltage is independent of supply voltage variations, but the circuit is particularly prone to variations in the manufacturing process and requires the generated voltage to take on a single fixed value
Solution Approach 1:
The patent applies dynamics by making the reference voltage adjustable through a control signal that switches between different voltage generation paths. The circuit transitions from a fixed conventional DC generation approach to a dynamic system where the reference voltage can be adjusted based on operational requirements, resolving the contradiction between stability and manufacturing variations.
Solution Approach 2:
The patent segments the voltage generation into multiple paths: one path generates a first reference voltage when the supply voltage is within acceptable ranges, while another path generates a second reference voltage when the supply voltage exceeds the withstand limit. This segmentation allows the system to handle different operating conditions separately, avoiding the manufacturing precision issues of conventional single-path circuits.
2Temperature
If the generated reference voltage is set to achieve good temperature stability, then the voltage can only take on a single value determined by the generating circuit, but this voltage may be too low or too high for cascode structures operating at different supply voltage levels
Solution Approach 1:
The patent makes the reference voltage dynamic by introducing a control signal that selects between different voltage generation modes. When the supply voltage is normal, one reference voltage is generated; when the supply voltage exceeds the withstand limit, a different reference voltage is generated. This dynamic adjustment maintains temperature stability while adapting to different operating modes.
Solution Approach 2:
The patent creates a universal reference voltage generation system that can serve multiple functions: generating appropriate reference voltages for both normal operation and overvoltage protection modes. The single circuit architecture handles both cascode structure protection and temperature compensation requirements through multi-functional design.
3Power
If the difference between the generated reference voltage and the first supply voltage is high, then the generated voltage may be too low to be used as reference voltage for cascode structures, but if the generated voltage is high, then it may be too high when the first voltage is at lower values corresponding to low-power operating modes
Solution Approach 1:
The patent implements dynamic reference voltage adjustment based on the supply voltage level. A detection circuit monitors the supply voltage and controls the reference voltage generation accordingly: generating a first reference voltage for normal power modes and a second reference voltage for low-power modes. This dynamic behavior ensures reference voltage compatibility across different power consumption levels.
Solution Approach 2:
The patent uses feedback by having the control circuit continuously monitor the supply voltage level and adjust the reference voltage generation accordingly. The detection of supply voltage conditions feeds back to the reference voltage generation circuit, ensuring that the reference voltage remains compatible with the current operating mode of the cascode structures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively generates reference voltages that are stable, adaptable, and compatible with MOS transistors, enhancing the performance and reliability of cascode structures by reducing voltage-related issues and temperature dependencies.
Implementation Method 1
a first voltage divider bridge connected between a first supply node configured to receive a first supply voltage, and a second supply node configured to receive a reference potential
Implementation Method 2
a first MOS transistor and a second resistive voltage divider bridge connected in series between the first and second supply nodes, the first transistor having its gate connected to an intermediate node of the first bridge
Implementation Method 3
a first buffer circuit configured to be supplied with the first voltage, and comprising an input connected to a first intermediate node of the second bridge, and an output configured to deliver a first reference voltage
Data Source
AI summary
The present disclosure relates to a device (REFGEN) comprising: a first divider bridge (200) between a first node (202) at a supply voltage (VDDE) and a second node (204) at a reference potential (GND); a first transistor (Ten) and a second divider bridge (208) in series between the first and second nodes, the first transistor having its gate at the first bridge; a buffer circuit (BUFFa1) having an input (220) connected to a node (214) of the second bridge, and an output (218) delivering a reference voltage (VrefL); and a second transistor (To1) having its drain connected to the output of the buffer circuit, and its source connected to one of the first and second nodes. The first transistor (Ten) is OFF if the supply voltage (VDDE) is less than a threshold. The second transistor is ON if the first transistor is OFF, and vice versa.