Temperature-Compensated Oscillator Circuit for Stable Clock Cycles
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Solution Overview
Problem
Existing oscillators in semiconductor memory devices and IC chips are significantly influenced by changes in external voltage and temperature, causing instability in the clock signal cycle, which affects system synchronization.
Innovation Solution
An oscillator design that utilizes a reference voltage generator, shared by switch circuits and comparators, to compensate for changes in external voltage and temperature, incorporating NMOS and PMOS transistors, capacitors, and resistors to generate stable clock signals through an SR latch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common oscillator circuit is used, then the device complexity is low, but the clock signal cycle changes significantly with external voltage and temperature
Solution Approach 1:
The patent changes the operating parameters of the oscillator by introducing a reference voltage that varies with temperature and external voltage. This reference voltage is used to control the discharge time of capacitors in the oscillation circuit, thereby compensating for parameter changes due to environmental factors and maintaining stable clock signal cycle
Solution Approach 2:
The patent implements a feedback mechanism where the reference voltage generator continuously monitors temperature and external voltage changes, and adjusts the discharge time of the oscillation circuit accordingly. This feedback loop ensures that the clock signal cycle remains stable despite environmental variations
2Reliability
If RC delay effect circuits are used to stabilize clock signal, then the cycle stability improves, but the device complexity increases
Solution Approach 1:
The reference voltage generated by the reference voltage generator is shared by multiple components including switch circuits and comparators. This multi-functional use of a single reference voltage source provides comprehensive compensation across different circuit stages without proportionally increasing device complexity
Solution Approach 2:
The patent divides the oscillation circuit into distinct functional modules: a reference voltage generator, switch circuits controlled by the reference voltage, and comparators. This segmentation allows each module to be optimized independently while working together to achieve stable clock signal generation
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 oscillator maintains a constant clock signal frequency despite variations in external voltage and temperature, enhancing the reliability of internal clock generation in semiconductor devices.
Implementation Method 1
The reference voltage generator may include a first resistor and a diode which are coupled in series between an external voltage terminal having the external voltage and a ground terminal
Implementation Method 2
a first capacitor configured to delay the discharge time of the first node, a third switch configured to control discharging of the first node according to the level of the reference voltage
Data Source
AI summary
An oscillator includes a reference voltage generator configured to generate a reference voltage varying according a change in temperature and an external voltage, a first comparison voltage generator configured to output a first comparison voltage to a first node in response to the reference voltage, a second comparison voltage generator configured to output a second comparison voltage to a second node in response to the reference voltage, a first comparison circuit configured to compare the reference voltage and the first comparison voltage and to generate a first input voltage as a result of the comparison, a second comparison circuit configured to compare the reference voltage and the second comparison voltage and to generate a second input voltage as a result of the comparison, and a clock generator configured to output a clock signal that oscillates in response to the first and second input voltages.