External Device Calibration for IC Analog Parameter Accuracy
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Solution Overview
Problem
Existing methods for calibrating integrated circuit (IC) parameters, such as RC oscillation frequency, face inaccuracies due to increased costs associated with hardware calibration and limitations of non-volatile memory programming, particularly with low-cost EPROMs that can only be programmed once, while high-cost EEPROMs or flash ROMs offer re-programmability but at a higher expense.
Innovation Solution
A method involving an external device that alternates between a testing mode and a calibrating mode to input initial values into a latch register, detect output values, and adjust them to predetermined ranges, with calibrated values being written into non-volatile memory, utilizing a programmer or testing machine to optimize oscillation frequencies and supply voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hardware fuse pads are added to calibrate output parameters, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The calibration function is extracted from the IC itself and performed by an external device. The external device reads the output parameter, compares it with the target range, and writes calibration data back to the IC's non-volatile memory, eliminating the need for complex internal calibration hardware.
Solution Approach 2:
An external device acts as an intermediary between the IC and the calibration process. This intermediary performs the calibration measurements and data writing, simplifying the IC's internal structure while maintaining calibration capability.
2Ease of manufacture
If EPROM is used for non-volatile memory, then cost is reduced, but adaptability decreases due to single programming capability
Solution Approach 1:
The calibration process is performed in advance during manufacturing or testing, and the calibration data is written to the EPROM before the product is shipped. Since EPROM can be programmed once with high precision, the preliminary calibration action ensures the device operates within specifications without needing re-programmability.
3Adaptability or versatility
If EEPROM or flash ROM is used for non-volatile memory, then adaptability is improved through re-programmability, but cost increases
Solution Approach 1:
The patent uses EPROM, a cheaper memory type that can be programmed once with high precision. The calibration is performed once during manufacturing, making the re-programmability feature unnecessary. This approach sacrifices adaptability for cost efficiency, which is acceptable for mass-produced devices where calibration is done upfront.
4Device complexity
If calibration is performed outside the IC, then device complexity is reduced, but measurement precision may be affected by external factors
Solution Approach 1:
An external device serves as an intermediary that performs the measurement and calibration functions. This external device can be a precision instrument or testing equipment that provides accurate measurements without requiring complex internal calibration circuits in the IC.
Data Source
AI summary
A method for calibrating a parameter of an IC, using an external device so as to calibrate an analog control parameter of an internal analog circuit in the IC. The external device is used in a detecting mode so as to detect whether the analog control parameter is beyond a pre-determined range. If the analog control parameter is beyond the pre-determined range, the external device is used in a calibrating mode so as to obtain a calibrated value and the calibrated value is then written into the internal analog circuit in the IC. The external device is used for detection and calibration repeatedly until the analog control parameter is within the pre-determined range. When the analog control parameter is within the pre-determined range, the calibrated value is written into a non-volatile memory in the IC.