Current Generator Temperature Compensation Single Thermistor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current systems for sensing output current in multiphase power supplies face errors due to temperature-dependent resistance in output inductors, leading to costly solutions that require multiple thermistors for temperature compensation, which increase costs and complexity.
Innovation Solution
A novel current generator architecture that compensates for temperature differences using a single NTC thermistor by comparing voltage drops across the thermistor and a reference resistor, generating a compensation current that can be replicated for various applications without knowing the thermistor's temperature characteristic, utilizing a current mirror and feedback circuit to produce a proportional output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple thermistors are used for temperature compensation of each phase current, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple temperature compensation functions into a single thermistor by summing the phase currents through current mirrors before applying temperature compensation. Instead of using separate thermistors for each phase, one thermistor compensates the aggregated current signal, reducing component count while maintaining compensation accuracy.
Solution Approach 2:
The single thermistor serves multiple compensation purposes simultaneously - it compensates the summed current from all phases and provides a universal temperature reference that can be applied to multiple current sensing channels, making one component perform the work of several.
2Device complexity
If a single thermistor is used for average temperature compensation, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent performs preliminary current summation through current mirrors before temperature compensation is applied. By aggregating the phase currents first and then applying the single thermistor's compensation to the summed signal, the system achieves accurate compensation without needing multiple thermistors.
Solution Approach 2:
The system uses feedback through current mirrors to replicate and sum the phase currents, creating an aggregated signal that reflects the total system current. The single thermistor then provides temperature compensation feedback to this summed signal, ensuring accurate temperature compensation across all phases.
3Measurement precision
If temperature compensation is implemented, then measurement precision is improved, but device complexity increases due to additional components
Solution Approach 1:
The patent merges the temperature compensation function into the existing feedback network by integrating the thermistor with the ZFB resistance. This combination approach incorporates temperature compensation without adding a completely separate compensation network, reducing overall system complexity.
Solution Approach 2:
The compensation network using a single thermistor serves multiple functions - it provides temperature compensation for current sensing and can be integrated with the existing feedback mechanism, making the compensation structure multi-functional rather than a separate additive 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
This solution allows for accurate temperature compensation of output currents without additional thermistors, reducing costs and maintaining thermal stability during load transients, enabling efficient current sharing and monitoring across phases.
Implementation Method 1
A current generator for temperature compensation receives as input current to be compensated a function of a difference between a temperature of an environment and a reference temperature
Implementation Method 2
a current mirror adapted to generate a replica current of the input current to be compensated
Implementation Method 3
at least a feedback circuit adapted to generate the output compensation current proportional to the difference between the voltages on the reference resistor and on the thermistor
Data Source
AI summary
A current generator includes a thermistor configured to receive an input current, a reference resistor having a resistance substantially corresponding to a resistance of said thermistor at a reference temperature, a current mirror configured to generate a mirrored current proportional to said input current, a feedback circuit configured to generate an output compensation current proportional to a difference between voltages on said reference resistor and on said thermistor, and a first adder configured to force through said reference resistor a difference current between said mirrored replica current and said output compensation current.