CMOS Voltage Reference Circuit With Temperature Compensation
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Solution Overview
Problem
Traditional reference voltage (VREF) generation circuits in 3D NAND memory are susceptible to fluctuations due to changing operating temperatures, leading to insufficient voltage headroom and operation in a saturation region, which increases power consumption and affects performance.
Innovation Solution
A voltage generation circuit that includes a first circuit with transistors and resistors, a compensation current to account for temperature variations, and tunable resistors to maintain a stable reference voltage (VREF) across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional reference voltage generation circuits are used, then the circuit structure is simple, but the reference voltage fluctuates with operating temperature
Solution Approach 1:
The voltage generation circuit is divided into multiple independent branches: a first branch with transistors operating in linear region, a second branch with transistors operating in saturation region, and a third branch with resistors. Each branch generates voltage with different temperature coefficients, and their parallel combination achieves temperature compensation while maintaining manageable circuit complexity
Solution Approach 2:
The patent combines different types of circuit elements (transistors in linear region, transistors in saturation region, and resistors) in parallel to create a composite voltage generation circuit. Each element type contributes differently to the overall temperature response, and their combination produces a reference voltage that is stable across temperature variations
2Reliability
If transistors operate in saturation region, then the circuit operation is simplified, but the reference voltage becomes sensitive to temperature changes
Solution Approach 1:
The patent separates the transistor operations into different regions by creating distinct branches: one branch with transistors operating in linear region and another with transistors operating in saturation region. This segmentation allows each branch to contribute different temperature characteristics, achieving overall temperature stability while maintaining clear operational definitions for each component
Solution Approach 2:
The patent changes the operating region parameter of transistors from exclusively saturation region to including linear region operation. By adjusting the operating region parameter and combining it with resistor-based voltage division, the circuit achieves temperature stability without sacrificing operational simplicity
3Use of energy by moving object
If voltage headroom is reduced to lower power consumption, then power efficiency improves, but the reference voltage becomes more sensitive to temperature variations
Solution Approach 1:
The patent employs dynamic temperature compensation by using transistors whose operating characteristics change with temperature. The combination of linear-region transistors, saturation-region transistors, and resistors creates a dynamically balanced system that automatically compensates for temperature effects, maintaining reference voltage stability across the operating temperature range while operating at low voltage headroom
Solution Approach 2:
The patent creates a composite voltage generation system combining multiple circuit elements with different temperature responses. This composite structure allows the circuit to achieve temperature stability without requiring increased voltage headroom, as each element type compensates for the temperature sensitivity of others
Data Source
AI summary
A voltage generation circuit for high performance and high capacity three-dimensional (3D) NAND memory that receives an input control current and outputs a VREF is provided. The voltage generation circuit includes a first circuit including first and second transistors connected in series between a first node receiving the input control current and a supply node, a second circuit including first and second resistors connected in series between the first node and the supply node, wherein the input control current is divided between the first and second circuits, reference node outputs VREF and is connected to the first transistor, a second node located between the first resistor and the second resistor and in electrical communication with the second transistor, and a current supply circuit connected to the second node and providing a compensation current that influences VREF to account for changes in operating temperatures.