PTAT Signal Circuit with Feedback Linearization for Thermal Sensors
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Solution Overview
Problem
The linearity of PTAT signals in thermal sensors and bandgap reference circuits deteriorates in advanced semiconductor technology, necessitating a high linearity PTAT signal for accurate temperature measurement.
Innovation Solution
A signal generating device comprising a first and second circuit with control circuits to adjust currents and voltages, utilizing p-type FETs and BJTs, and differential amplifiers to equalize base signals and generate a PTAT current that is independent of current gains, ensuring improved linearity in response to absolute temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional PTAT circuit is used to generate temperature signals, then the circuit structure is simple, but the linearity of the PTAT signal deteriorates in advanced semiconductor technology
Solution Approach 1:
The patent divides the PTAT signal generation into multiple stages: a conventional PTAT circuit generates an initial signal, which is then processed through additional control circuits that segment the signal correction functions. This allows improved linearity while managing complexity through functional decomposition.
Solution Approach 2:
The patent introduces intermediary control circuits between the conventional PTAT circuit and the final output. These control circuits act as mediators that adjust and correct the PTAT signal, improving linearity without requiring complete redesign of the entire signal generation system.
2Volume of moving object
If advanced semiconductor technology is used to improve integration, then device size is reduced, but the linearity of PTAT signals deteriorates
Solution Approach 1:
The patent changes key circuit parameters including current ratios, voltage levels, and transistor sizing to compensate for process variations in advanced technology nodes. By adjusting these parameters, the circuit maintains high linearity despite the physical scaling inherent in advanced semiconductor manufacturing.
3Measurement precision
If control circuits are added to adjust currents and improve linearity, then PTAT signal accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple control functions into integrated control circuits that perform multiple corrections simultaneously. By combining functions such as current matching, voltage regulation, and linearity correction into unified circuits, the patent improves temperature measurement accuracy while minimizing the increase in overall device complexity.
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 enhances the linearity of PTAT currents and reference voltage signals, reducing temperature errors and maintaining stability across varying temperatures, thereby improving the accuracy of thermal sensors and bandgap reference circuits.
Implementation Method 1
The PTAT circuit uses the electrical characteristics of the voltage difference between two base-emitter voltages, i.e. delta VBE, to generate the PTAT signal
Implementation Method 2
The first control circuit is coupled to the first circuit and the second circuit for generating a first adjusting current and a second adjusting current to the first circuit and the second circuit
Data Source
AI summary
A signal generating device includes: a first circuit arranged to generate a first current to a first bipolar junction transistor therein; a second circuit coupled to the first circuit via an output terminal for generating a second current to a second BJT therein; and a first control circuit coupled to the first circuit and the second circuit, for generating a first adjusting current and a second adjusting current to the first circuit and the second circuit for adjusting the first current and the second current such that the first circuit and the second circuit outputs a temperature-dependent signal on the output terminal.