Transmitter Self-Testing via Phase Interpolation
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Solution Overview
Problem
Existing data communication transmitter circuits require a receiver for built-in-self testing, which is inefficient and resource-intensive, especially when testing is needed before coupling with a receiver, and involves the use of clock data recovery (CDR) and loop-back receivers.
Innovation Solution
Implementing a transmitter testing method using interpolation, where a pre-defined data pattern is generated and sampled at different interpolation phase positions without the need for a receiver, utilizing a phase interpolator to create an interpolated clock signal and a pattern checker to verify data transmission accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a receiver is used for built-in-self testing of the transmitter, then the transmitter can be tested, but the testing becomes resource-intensive and requires additional circuit components
Solution Approach 1:
The patent extracts the essential testing function from the receiver and implements it independently using a phase interpolator and pattern checker. The receiver is completely removed from the testing process, and only the necessary minimal components (phase interpolator, pattern checker, and associated logic) are retained to perform the testing function, thereby reducing device complexity while maintaining testing capability.
Solution Approach 2:
The patent creates a simplified copy of the receiver's testing function through the phase interpolator and pattern checker combination. Instead of using the full receiver, a functional equivalent is constructed using available transmitter resources, allowing the transmitter to test itself without external equipment or additional receiver components.
2Productivity
If clock data recovery (CDR) and loop-back receivers are used for testing, then the transmitter can be tested at normal data rates, but power consumption and area requirements increase
Solution Approach 1:
The transmitter uses its own internal resources (phase interpolator, pattern checker, and existing data paths) to perform self-testing without requiring external CDR circuits or loop-back receivers. The testing is accomplished using the transmitter's own operational data flow, eliminating the need for separate power-intensive testing subsystems while maintaining the ability to test at normal data rates.
3Reliability
If a full receiver is used for testing the transmitter, then comprehensive testing can be performed, but the area requirements and resource usage increase
Solution Approach 1:
The patent extracts only the essential testing functionality from the receiver and implements it using minimal circuit elements. The phase interpolator and pattern checker together provide comprehensive transmitter testing without requiring the full receiver architecture, thereby significantly reducing the circuit area occupied by testing components while maintaining testing effectiveness.
Data Source
AI summary
Various embodiments provide for testing a transmitter with interpolation, which can be used with a circuit for data communications, such as serializer/deserializer (SerDes) communications. In particular, some embodiments provide for data transmission test of a transmitter by: generating and outputting a pre-determined data pattern through a serializer of the transmitter; sampling a serialized data output of the serializer over a plurality of different interpolation phase positions of a phase interpolator; and using a pattern checker to error check the sampled data over the plurality of different interpolation phase positions to determine whether the data transmission test passes.