NFC Circuit Powering SIM Card at Low Battery
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Solution Overview
Problem
Existing NFC telecommunications systems face challenges in maintaining NFC support when the battery level is low or the device is switched off, as initial solutions either require external components that introduce voltage drops or have limited autonomy and complex software requirements.
Innovation Solution
A method that measures the battery level and switches to powering the SIM card through the NFC circuit when the battery is low, allowing NFC transactions even with very low battery voltage, without the need for external modules and with minimal software configuration, thereby enabling extended NFC transaction capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the SIM card is powered through the chipset when battery level is low, then the SIM card can be powered, but the voltage level becomes insufficient for NFC transactions
Solution Approach 1:
The NFC circuit acts as an intermediary power source between the battery and the SIM card. When the battery voltage drops below the threshold, the NFC circuit takes over the power supply function through its dedicated power contact, ensuring the SIM card receives sufficient voltage for NFC transactions even when the main chipset is powered down.
Solution Approach 2:
The system dynamically switches the power source for the SIM card based on battery level conditions. When battery voltage is sufficient, the chipset powers the SIM card; when voltage drops below the threshold, the system transitions to NFC circuit power supply, enabling adaptive operation across varying battery conditions.
2Adaptability or versatility
If an external switch component is added to enable SIM card powering in both ON and OFF modes, then card emulation support is improved, but voltage drop occurs on the VSIM contact
Solution Approach 1:
The external switch component is removed from the system. Instead of adding a DUAL P-Channel switch between the chipset and NFC circuit, the invention uses the existing NFC circuit power contact to directly power the SIM card when needed, eliminating the source of voltage drop while maintaining dual-mode operation capability.
3Duration of action of stationary object
If the system enters simulated OFF mode to maintain SIM card power, then NFC transactions can continue, but software complexity increases and autonomy is limited
Solution Approach 1:
The power management is segmented into two independent pathways: one through the chipset for normal operation, and another through the NFC circuit for low-battery operation. This segmentation allows the system to maintain SIM card power without requiring complex simulated OFF mode software, as the NFC circuit provides a dedicated alternative power path that can be activated independently.
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 allows NFC transactions to be performed even when the battery is very low, with extended autonomy and reduced software complexity, ensuring consistent voltage levels and maintaining SIM card certification standards.
Implementation Method 1
An NFC reader (such as an NFC interface of a Point of Sales terminal, a.k.a POS, at a bakery), with which the user wishes to interact, may actively generate a radio frequency field that can power a passive target. The passive target may be a SIM card connected to an antenna embedded in a cell phone.
Data Source
AI summary
There is described a method for establishing an NFC connection between a subscriber identity module (SIM) and an NFC device (RDR). The subscriber identity module (SIM) is connected to a telecommunications system (CELL_P) through contacts (VCC, RST, CLK, D+, GND, SWP, IO, D−) of the telecommunications system (CELL_P). The telecommunications system (CELL_P) comprises a chipset (CHP) and an NFC circuit (NFCC). The method comprises measuring the level of charge of a battery (BATT) powering the telecommunications system (CELL_P) with a battery gauge. Based on the measurement, the method selects the source for supplying power to the subscriber identity module (SIM) and configures the wiring of the subscriber identity module (SIM). The disclosure also relates, in particular, to a telecommunications system, to a computer program, and to a storage medium.