LO Buffer Reuse for Low-Power Loop-Back Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current loop-back test designs for communication systems, such as RADAR systems, are costly and power-intensive due to the need for a separate testing tone generator and extensive circuit enablement during low-power scan modes.
Innovation Solution
The design reuses a local oscillator (LO) buffer for both loop-back test and transmission functions, utilizing an auxiliary path to enable or disable loop-back paths, thereby eliminating the need for a separate testing tone generator and reducing power consumption by disabling unnecessary circuit components during low-power operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate testing tone generator (TTG) is implemented in the vicinity of RX chains to provide testing tone for testing each of RX chains, then loop-back test functionality is achieved, but chip area consumption increases and cost effectiveness decreases
Solution Approach 1:
The LO buffer is designed to perform multiple functions: it serves as the local oscillator buffer for normal RX operation and simultaneously functions as a testing tone generator for loop-back tests. By configuring the LO buffer to generate and provide test tones to the RX chain during test modes, the patent eliminates the need for a separate TTG circuit, thereby reducing chip area while maintaining test functionality.
2Adaptability or versatility
If the normal TX chain is enabled under low-power scan mode to provide transmission capability, then transmission functionality is achieved, but power consumption increases due to too many blocks being enabled
Solution Approach 1:
The patent extracts the essential transmission capability from the full TX chain and implements it using only the necessary minimum components. Specifically, the LO buffer is configured to generate RF signals for scanning operations without requiring the full TX chain blocks (such as power amplifiers, modulators, etc.) to be enabled. This selective extraction of only the essential LO buffering and signal generation functions enables transmission capability while keeping power consumption low by leaving other TX chain blocks disabled.
3Area of stationary object
If the LO buffer is reused for both loop-back test and transmission functions, then cost and chip area are reduced, but circuit complexity increases due to multiple function sharing
Solution Approach 1:
The patent implements dynamic reconfiguration of the LO buffer to adapt its function based on operational mode. During normal RX operation, the LO buffer performs its standard function of buffering local oscillator signals for down-conversion. During loop-back test modes, the same LO buffer is dynamically reconfigured to generate and output test tones. This dynamic switching between functions is controlled through mode-select signals that reconfigure the LO buffer's internal circuitry, allowing one circuit to perform multiple functions without requiring separate dedicated circuits for each function.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A semiconductor chip includes a first wireless communication circuit, a local oscillator (LO) buffer, and an auxiliary path. The first wireless communication circuit has a signal path, wherein the signal path has a mixer input port and a signal node distinct from the mixer input port. The auxiliary path is used to electrically connect the LO buffer to the signal node of the signal path. The LO buffer is reused for a loop-back test function through the auxiliary path.