PTAT Sensor Dynamic Switching for Mismatch Compensation
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Solution Overview
Problem
Conventional PTAT sensing circuits experience sensing errors due to mismatches in circuit components during the IC manufacturing process, which affect the accuracy of temperature detection.
Innovation Solution
A PTAT sensor design that includes a control unit, a sensing unit with switchable connection configurations, and a calculation unit to generate a PTAT voltage value by interchanging the connections of circuit components with matching relationships, thereby reducing sensing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional PTAT sensing circuit uses fixed circuit components (transistors, resistors), then the circuit structure is simple, but component mismatches during IC manufacturing cause sensing errors
Solution Approach 1:
The patent implements dynamic switching between multiple connection configurations for circuit components. The switch unit can change the connection relationship between transistors and resistors based on control signals, allowing the circuit to adapt between different configurations. This dynamic structure enables the system to compensate for component mismatches by selecting optimal configurations, thereby improving temperature sensing accuracy without being limited to a single fixed circuit arrangement.
Solution Approach 2:
The patent changes the connection parameters of circuit components by switching between different connection configurations. Through the switch unit, the circuit can alter the topological parameters of component connections, such as changing which transistors are connected in series or parallel, and which resistors are activated. This parameter variation allows the circuit to compensate for manufacturing variations in component values, maintaining high sensing accuracy despite component mismatches.
2Measurement precision
If the PTAT sensing circuit uses interchangeable connection configurations to reduce mismatch errors, then sensing accuracy improves, but the circuit complexity and control requirements increase
Solution Approach 1:
The patent segments the circuit into modular functional units with dedicated switch units for each component pair. Each switch unit independently controls the connection configuration of specific transistors and resistors, allowing flexible recombination of circuit segments. This segmentation enables the system to generate multiple connection configurations by selectively activating different component combinations, improving sensing accuracy while maintaining manageable circuit complexity through modular design.
Solution Approach 2:
The patent designs the circuit components and switch units to serve multiple functions across different connection configurations. The same transistors and resistors can be used in various configurations depending on the control signals, making the circuit universally adaptable to different sensing conditions. This multi-functionality reduces the need for separate dedicated components for each configuration, thereby improving sensing accuracy without proportionally increasing overall circuit complexity.
3Measurement precision
If the circuit uses switch units to change connection configurations, then component mismatch impact is reduced, but the device requires additional control signals and switching components
Solution Approach 1:
The patent employs periodic or sequential activation of different connection configurations through control signals. The switch units can be activated in a systematic sequence to cycle through different circuit configurations, allowing the sensing circuit to sample multiple states. This periodic action enables the system to compensate for component mismatches by sequentially testing different configurations, improving sensing accuracy while using efficient control signal sequences that minimize overall 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 design significantly reduces sensing errors caused by component mismatches, improving the accuracy of temperature detection by averaging voltage values obtained from different connection configurations.
Implementation Method 1
a PTAT sensing circuit applies a pair of bipolar junction transistors (BJTs) to sense the temperature. When collector current densities of transistors Q4 and Q5 are different, a collector voltage difference (ΔVEB) between the transistors Q4 and Q5 satisfies Formula 1: ΔVEB=VT ln [(IC4/A4)/(IC5/A5)]
Data Source
AI summary
A proportional to absolute temperature (PTAT) sensor is capable of reducing a sensing error resulted from a mismatch between circuit components. The PTAT sensor includes a control unit, a sensing unit and a calculation unit. The control unit generates a control signal. The sensing unit, comprising at least a pair of circuit components having a matching relationship, senses an absolute temperature under the first connection configuration and the second connection configuration respectively to generate a first voltage value and a second voltage value, wherein the first connection configuration and the second connection configuration are decided by interchanging the circuit connections of the pair of circuit components according to the control signal. And the calculation unit, coupled to the sensing unit, calculates a PTAT voltage value according to the first voltage value and the second voltage values.