NFC Power Reception Circuit Low Voltage Charging
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Solution Overview
Problem
Conventional power supply systems using NFC for non-contact charging face challenges in charging batteries from extremely low voltage states due to the operational limitations of microprocessors and require additional CPUs, increasing cost and chip size, while also resulting in prolonged charging times when using minimal communication protocols.
Innovation Solution
A power supply system that includes a power reception device with a power reception coil, a communication circuit for determining battery voltage and setting status and request parameters, and a switching circuit to connect between communication and power reception circuits, allowing for efficient power transfer and charging even at low voltage levels without relying on CPU operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a microprocessor is used to control non-contact charging, then complex communication protocols can be implemented, but charging cannot be performed when battery voltage is extremely low
Solution Approach 1:
A voltage threshold detection circuit is introduced as an intermediary between the battery and the microprocessor. This circuit detects when battery voltage falls below a threshold and automatically switches to a simplified communication mode, enabling the system to operate at low voltages without requiring microprocessor intervention for protocol selection.
Solution Approach 2:
The communication protocol is made dynamic by automatically switching between full-featured protocols (when voltage is sufficient) and simplified protocols (when voltage is low). This dynamic adaptation allows the system to maintain functionality across varying battery conditions without requiring multiple fixed configurations.
2Reliability
If an additional CPU is provided to enable charging at low voltage, then charging from 0% battery is possible, but device cost and chip size increase
Solution Approach 1:
The control functionality is segmented into two paths: a simplified control path that operates at low voltages using basic communication protocols, and a full-featured path that operates at normal voltages using the microprocessor. This segmentation allows the system to use minimal resources when needed without requiring a complete second processing unit.
Solution Approach 2:
The system performs self-service by automatically detecting voltage conditions and selecting appropriate communication modes without external intervention or additional processing power. The voltage detection circuit and switching logic enable the system to adapt its own operation based on battery state.
3Device complexity
If minimum communication protocols are used for charging, then device complexity is reduced, but charging time increases
Solution Approach 1:
The communication protocol complexity is made dynamic rather than static. The system uses simplified protocols only when necessary (at low voltages) and switches to full-featured protocols when voltage conditions permit, thereby optimizing charging speed without permanently increasing device complexity.
Solution Approach 2:
The system changes operational parameters (communication protocol selection) based on battery voltage conditions. When voltage is sufficient, parameters are adjusted to enable faster charging with full communication capabilities; when voltage is low, parameters are adjusted to maintain functionality with simpler protocols.
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
Enables rapid battery charging from extremely low voltage states without increasing device size, by switching between communication and power reception modes and using fixed parameters when the battery voltage is low, thus overcoming the limitations of conventional systems.
Implementation Method 1
a power transmission coil TC, and a power reception coil RC
Data Source
AI summary
A power reception device includes a communication circuit for transmitting an information packet that includes a status parameter indicating the status of the battery and a request parameter indicating the amount of transmission power and a transmission time; a power reception circuit for receiving power and charging the battery; and a switching circuit for switching between the communication circuit and the power reception circuit, to connect a power reception coil to one of the communication circuit and the power reception circuit. The communication circuit includes determination circuit for determining the voltage of the battery; and a power reception control circuit for setting values corresponding to the voltage of the battery as the status parameter and the request parameter when the voltage of the battery is equal to or higher than a voltage threshold, and for setting fixed values as the parameters when the voltage of the battery is lower than the threshold.