Bandgap Reference PTAT Circuit for Improved Temperature Linearity
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Solution Overview
Problem
Advanced semiconductor technology leads to a deterioration in the linearity of PTAT signals used in thermal sensors and bandgap reference circuits, necessitating a solution for improved linearity in temperature-dependent signals.
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 maintain linearity of PTAT signals by equalizing base signals and currents, independent of current gains, thereby improving temperature response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If advanced semiconductor technology is used, then device integration and miniaturization are improved, but the linearity of PTAT signals deteriorates
Solution Approach 1:
The patent introduces control circuits as intermediary components between the PTAT signal generation stage and the output stage. These control circuits actively compensate for the non-linearity introduced by advanced semiconductor technology, mediating the signal to restore linearity without requiring a complete redesign of the underlying semiconductor process
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting circuit parameters (such as current ratios, voltage levels, or transistor operating points) through control circuits to compensate for the deterioration in PTAT signal linearity. This allows the system to adapt to the specific characteristics of advanced semiconductor technology while maintaining signal integrity
2Manufacturing precision
If control circuits are added to adjust currents and voltages, then linearity of PTAT signals is improved, but device complexity increases
Solution Approach 1:
The patent divides the control function into separate control circuits that can be independently designed and optimized. By segmenting the complexity into modular control blocks, each handling specific aspects of signal adjustment, the overall system becomes more manageable and the complexity is distributed rather than concentrated in a single complex unit
Solution Approach 2:
The control circuits are designed to perform multiple functions simultaneously - adjusting currents, regulating voltages, and compensating for non-linearities all within the same circuit blocks. This multi-functionality reduces the total number of separate components needed, thereby limiting the increase in device complexity while achieving the desired linearity improvement
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 voltages in response to absolute temperature, reducing temperature errors and maintaining stability of reference voltages, achieving improved performance in 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
Data Source
AI summary
A signal generating device including a first circuit coupled between a first reference voltage and a second reference voltage and arranged to generate a first current to a first BJT; a first control circuit connected to the first BJT and arranged to adjust the first current. The first circuit outputs a part of a temperature-dependent signal on an output terminal, and includes: a first active device having a first and a second connecting terminal coupled to the first BJT; a second active device having a first connecting terminal coupled to the first BJT, and a second connecting terminal coupled to a second reference voltage; a first amplifier having an input terminal coupled to the first BJT, and an output terminal coupled to the control terminal of the first active device; and a second control circuit coupled to the first circuit for controlling the temperature-dependent signal according to the first current.