Voltage Reference Trimming With Local Heating and Thermal Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing voltage reference generation circuits face challenges in achieving precise, temperature-insensitive reference voltages due to variability in device parameters, requiring time-consuming calibration processes that can damage components and are inefficient with non-uniform thermal profiles.
Innovation Solution
A voltage reference generator with a local heater for continuous temperature control, temperature-compensated resistances, current mirrors, digital modulators, and a DAC to generate a constant reference current, using pulse width or density modulation to trim resistances for precise temperature compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wafer heating is used for calibration, then temperature drift reduction is achieved, but production time increases due to large heating time constant
Solution Approach 1:
The invention divides the heating function into two distinct components: a global wafer heater for overall temperature control and local on-chip heaters for targeted calibration. This segmentation allows simultaneous operation at different temperature points, reducing total calibration time while maintaining temperature drift reduction accuracy.
Solution Approach 2:
The invention performs preliminary calibration actions by heating the wafer to elevated temperatures before final device operation. This preliminary heating allows calibration to occur in advance, and the system maintains temperature compensation across the operating range based on these preliminary measurements, reducing actual production cycle time.
2Loss of time
If on-chip heating elements are used, then heating time constant is reduced, but non-uniform thermal profile and unknown die temperature occur
Solution Approach 1:
The invention introduces temperature sensors as intermediaries between the heating elements and the reference circuit. These sensors provide real-time feedback on actual die temperature, enabling precise temperature control and uniform thermal profiling despite the use of localized heating elements.
Solution Approach 2:
The system implements feedback control by continuously monitoring die temperature with sensors and adjusting heater power accordingly. This closed-loop control ensures uniform thermal profile and known die temperature, resolving the non-uniformity issue while maintaining fast heating response.
3Productivity
If excessive heating is applied, then calibration speed increases, but permanent damage to die components occurs
Solution Approach 1:
The invention uses dynamic, adaptive heating control where the heating power is continuously adjusted based on real-time temperature feedback. This allows rapid heating when needed while automatically reducing power as target temperatures are approached, preventing overheating and component damage while maintaining calibration speed.
Solution Approach 2:
The system incorporates protective measures by setting predetermined temperature thresholds and maximum power limits before calibration begins. The feedback control system acts as a cushion against excessive heating, preventing permanent damage while still enabling fast calibration through controlled thermal ramps.
4Reliability
If multiple temperature points are calibrated, then temperature drift accuracy improves, but calibration time becomes impractical
Solution Approach 1:
The invention segments the calibration process into parallel operations using multiple local heaters that can be activated simultaneously at different temperature points. This allows multiple temperature calibrations to occur concurrently rather than sequentially, maintaining high accuracy while reducing total calibration time to practical levels.
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
Enables precise, temperature-insensitive reference voltages by achieving continuous thermal profiles and minimizing voltage drift, reducing production time and equipment needs while ensuring component safety.
Implementation Method 1
MOS MN1, generating heat by thermal effect from ohmic loss of current flowing through the drain to source terminals of MOS MN1
Data Source
AI summary
Embodiments of the present disclosure may relate to a voltage reference generator comprising: a local heater structured to generate continuous controlled temperature and uniform thermal profile, at multiple points further comprising a Bipolar Junction, Transistors, and a heating element. Embodiments may additionally include temperature compensated resistances adopted to generate constant temperature compensated voltage reference current using an operational amplifier, a transistor, and two or more resistors, positive and negative. The embodiments may further include, current mirrors comprising a plurality of MOS transistors configured to mirror current flowing in the PMOS transistor. Further embodiments may include, digital modulators structured to generate modulated control signals, the control signals being structured to control a temperature by trimming change in the voltage reference, and a Digital to Analog Converter configured to generate output current proportional to a current reference mirrored in one or more of the plurality of transistors.