DRAM Temperature Measurement Circuit for Low-Voltage Resolution
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Solution Overview
Problem
Existing temperature measurement systems in integrated circuits face limitations in resolution, power consumption, and require band-gap type tuning, and fail to ensure adequate operation at low voltages, particularly in dynamic random access memory (DRAM) devices.
Innovation Solution
A temperature measurement system utilizing a comparator with a switch and integrator, employing currents proportional and complementary to absolute temperature (IPTAT and ICTAT) and voltage complementary to absolute temperature (VCTAT) to enhance resolution and operate effectively at lower voltages without precision analog components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precision analog components are used in the reference circuit to produce temperature independent current and voltage, then the reference signals are stable and accurate, but the device complexity and manufacturing cost increase, and band-gap type tuning is required
Solution Approach 1:
The patent extracts the temperature dependency from the reference circuit by using PTAT currents and CTAT voltages that inherently track temperature changes, eliminating the need for complex precision analog components and band-gap tuning circuits while maintaining reference signal stability
Solution Approach 2:
The patent creates simplified copies of temperature reference functions using current mirrors and voltage replication techniques with PTAT/CTAT characteristics, achieving temperature independent references without copying complex band-gap circuitry
2Measurement precision
If traditional sigma-delta converter design is used, then the conversion function is achieved, but the resolution is insufficient and adequate operation at low voltages (1.2V and below) cannot be ensured
Solution Approach 1:
The patent changes the operating parameters of the sigma-delta converter by using PTAT currents and CTAT voltages with optimized ratios, enabling high-resolution temperature measurement at low voltages while controlling power consumption through parameter optimization rather than increasing circuit complexity
3Manufacturing precision
If band-gap type tuning is implemented to achieve temperature independent references, then the reference accuracy is improved, but the manufacturing process becomes more complex and costly
Solution Approach 1:
The patent implements self-service temperature compensation where the PTAT current and CTAT voltage automatically track and compensate for temperature changes without external tuning, eliminating the need for complex band-gap tuning processes while maintaining reference accuracy
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 system achieves improved resolution and operational efficiency at lower voltages, eliminating the need for costly precision analog components and ensuring adequate performance across a wider temperature range.
Implementation Method 1
an integrator which generates a voltage signal proportional to an absolute temperature by integrating a temperature dependent current
Data Source
AI summary
A converter comprising a comparator having a first input operable to receive a first signal, a second input operable to receive a second signal, and an output, a switch for sinking a portion of the first signal, wherein the switch is responsive to the output, and an integrator connected to the first input, wherein the first signal is a voltage developed by the integrator when a current proportional to the absolute temperature is applied thereto. A method for measuring temperature of a device using a comparator and converting the bitstream of the comparator to a digital output is also given. Because of the rules governing abstracts, this abstract should not be used to construe the claims.