Temperature-Compensated Current Mirror Circuit Without External Resistors
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Solution Overview
Problem
Current integrated circuit designs face challenges in generating temperature-independent constant currents without increasing circuit complexity or requiring additional output pins and external resistors, which complicates encapsulation and increases costs.
Innovation Solution
A current generation circuit comprising a temperature sensing circuit, a resistor element, and a current mirror circuit, where the temperature sensing circuit generates a reference voltage corresponding to temperature, and the resistor element determines the reference current based on this voltage, ensuring that both the reference and output currents remain constant regardless of temperature changes, without the need for additional output pins or external resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a feedback system including inductors and transformers is used to generate temperature-independent constant current, then the current stability is improved, but the circuit complexity increases
Solution Approach 1:
The patent extracts the temperature sensing function into a separate temperature sensing circuit that generates a reference voltage with temperature coefficient, and combines it with a resistor element having opposite temperature coefficient. This extraction allows the complex feedback system to be replaced by a simpler configuration that achieves the same temperature compensation effect without requiring inductors and transformers.
Solution Approach 2:
The patent changes the parameter approach by using voltage and resistance with specific temperature coefficients (positive or negative) to achieve temperature-independent current. Instead of using complex feedback control, the invention relies on selecting components with complementary temperature characteristics that naturally compensate for each other, thereby simplifying the circuit while maintaining current stability.
2Adaptability or versatility
If additional output pins are added to provide temperature-independent constant voltages to external resistors, then the current generation capability is improved, but the encapsulation difficulty increases
Solution Approach 1:
The patent merges the voltage output function and current generation function into a single integrated circuit. The temperature sensing circuit, resistor element, and current mirror circuit work together internally to generate both the reference voltage and the final output current without requiring external resistors or additional output pins, thereby simplifying the encapsulation process while maintaining full current generation capability.
Solution Approach 2:
The integrated circuit performs multiple functions within a single device: temperature sensing, reference voltage generation, current mirroring, and output current generation. This multi-functionality eliminates the need for separate external components and additional output pins, allowing the circuit to generate temperature-independent constant currents directly while simplifying manufacturing and encapsulation.
3Manufacturing precision
If external resistors are used to generate temperature-independent constant currents from constant voltages, then the current precision is improved, but the manufacturing cost increases
Solution Approach 1:
The patent implements self-service by incorporating the temperature compensation function directly into the integrated circuit. The temperature sensing circuit automatically detects temperature changes and adjusts the reference voltage accordingly, while the internal resistor element with opposite temperature coefficient provides automatic compensation. This self-regulating mechanism eliminates the need for external resistors, maintaining current precision while reducing manufacturing costs.
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
This solution allows for the generation of temperature-independent constant currents within integrated circuits with simpler circuit structures, reducing complexity and costs by eliminating the need for external components, while maintaining current stability across varying temperatures.
Implementation Method 1
The temperature sensing circuit and the resistor element both have positive temperature coefficients or negative temperature coefficients
Implementation Method 2
The resistor element is coupled with the temperature sensing circuit, and is configured to determine magnitude of a reference current according to the reference voltage and the resistance
Implementation Method 3
The current mirror circuit is coupled with the temperature sensing circuit, and is configured to generate an output current according to the reference current
Data Source
AI summary
A current generation circuit includes a temperature sensing circuit, a resistor element having a resistance, and a current mirror circuit. The temperature sensing circuit is configured to generate a reference voltage having corresponding magnitude according to a temperature of the current generation circuit. The resistor element is coupled with the temperature sensing circuit, and is configured to determine magnitude of a reference current according to the reference voltage and the resistance. The current mirror circuit is coupled with the temperature sensing circuit, and is configured to generate an output current according to the reference current. The temperature sensing circuit and the resistor element both have positive temperature coefficients or negative temperature coefficients.