Shared PLL/FLL Switching for Contactless CE-to-P2P Mode Change
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Solution Overview
Problem
Conventional contactless communication devices require a supplemental phase locked loop to switch from card emulation (CE) mode to peer to peer (P2P) mode, leading to increased power consumption, larger device area, and additional time for switching, as well as potential interference between phase locked loops.
Innovation Solution
A contactless communication device configured with a phase locked loop and a frequency locked loop sharing a common controlled oscillator, where the phase locked loop is deactivated in P2P mode, allowing the frequency locked loop to quickly lock onto the reader carrier frequency, eliminating the need for a supplemental phase locked loop and reducing switching time to less than 56 microseconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a supplemental phase locked loop is used to switch from CE mode to P2P mode, then switching capability is improved, but power consumption increases
Solution Approach 1:
The patent combines the CE mode phase locked loop and P2P mode phase locked loop into a single shared phase locked loop structure. The same phase locked loop is configured to operate in different modes by switching its reference clock source and control parameters, eliminating the need for a supplemental phase locked loop and reducing power consumption while maintaining mode switching capability
Solution Approach 2:
The phase locked loop is designed with multi-functionality to serve both CE mode and P2P mode operations. By configuring the same hardware structure with different reference clocks and control parameters, it performs the functions of both mode-specific loops, reducing overall system complexity and power usage
2Adaptability or versatility
If a supplemental phase locked loop is added for mode switching, then mode transition capability is improved, but device area increases
Solution Approach 1:
The patent merges the CE mode phase locked loop and P2P mode phase locked loop into a single shared structure, eliminating duplicate hardware components. This consolidation reduces the overall device area while maintaining the ability to switch between modes through configuration changes rather than hardware additions
3Speed
If a supplemental phase locked loop is used for mode switching, then switching speed is improved, but switching time increases
Solution Approach 1:
The patent performs preliminary configuration of the phase locked loop during CE mode operation, maintaining readiness for P2P mode switching. The shared phase locked loop is kept in a state where it can quickly transition to P2P mode by switching reference clocks and control parameters, avoiding the need to initialize a supplemental loop and reducing switching time
4Adaptability or versatility
If multiple phase locked loops are used for mode switching, then mode flexibility is improved, but interference between loops occurs
Solution Approach 1:
The patent eliminates the source of interference by merging multiple phase locked loops into a single shared structure. This removes the harmful interactions between separate loops while maintaining mode flexibility through configurable reference clocks and control parameters that allow the same hardware to operate in different modes without interference
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 reduces power consumption, minimizes device area, and enhances switching speed and robustness, while avoiding interference between loops, providing a more efficient transition from CE to P2P mode.
Implementation Method 1
a phase locked loop and a frequency locked loop having in common the same controlled oscillator
Implementation Method 2
operating the frequency locked loop with a reference clock signal and a frequency set point depending on the reader carrier frequency
Implementation Method 3
the controlled oscillator is controlled for outputting an output oscillator signal having a frequency equal to the reader carrier frequency or to a multiple of the reader carrier frequency
Data Source
AI summary
An embodiment device comprises a phase locked loop and a frequency locked loop having in common the same controlled oscillator. The device is firstly placed in the card emulation mode at the beginning of a communication between the contactless communication device and a contactless reader, the firstly placing comprising synchronizing within the contactless device, an ALM carrier frequency with a reader carrier frequency by operating at least the phase locked loop, and upon reception by the contactless communication device of an indication sent by the reader indicating a further communication in a peer to peer mode with the reader, the device is secondly placed in the peer to peer mode, the secondly placing including deactivating the phase locked loop and operating the frequency locked loop with a reference clock signal and a frequency set point depending on the reader carrier frequency and the frequency of the reference clock signal.