Power Node Communication for Secure Device Authentication
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Solution Overview
Problem
Existing electronic device systems face challenges in securely delivering power to load devices without risking damage from unauthorized or defective connections, particularly in applications where regulatory safety limits, such as low leakage current, must be maintained.
Innovation Solution
The implementation of power node communication (PNC) using direct current (DC) power input terminals to facilitate device authentication and control, where a load device can modulate the DC output voltage to signal the source device, allowing for current limiting and authentication verification without separate communication interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the source device delivers full available operating energy to the load device upon physical connection without communication, then power delivery speed is improved, but device safety and authentication reliability deteriorate
Solution Approach 1:
The source device performs preliminary authentication and device detection before delivering full power. The source control circuit monitors the DC output node for authentication signals from the load device, and only after successful authentication does it enable the switch to provide full operating current. This preliminary verification ensures device safety while maintaining efficient power delivery.
2Reliability
If a separate communication interface is used for device authentication, then authentication reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the communication function with the power delivery interface. The load device communicates authentication signals by modulating the DC power node voltage, and the source device detects these signals through its existing power management circuitry. This eliminates the need for separate communication terminals and circuitry, reducing device complexity while maintaining authentication reliability.
Solution Approach 2:
The DC power interface serves dual functions: delivering operating energy and transmitting authentication signals. The same physical connection and control circuits handle both power delivery and device detection/communication, making the system more universal and reducing component count.
3Reliability
If current limiting is applied during authentication, then device safety is improved, but power delivery efficiency decreases
Solution Approach 1:
The current limiting is dynamic rather than static. During authentication, the source control circuit limits current to safe levels while monitoring for authentication signals. Upon successful authentication, the control circuit dynamically adjusts the current limit to allow full operating current flow. This dynamic adaptation ensures safety during the vulnerable authentication phase while maximizing power delivery efficiency afterward.
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 approach enables secure authentication and power delivery, ensuring that only authorized load devices receive full operating current while maintaining safety by limiting current to safe levels, thus preventing damage and adhering to regulatory safety standards.
Implementation Method 1
The load device can include a low-power communication circuit configured to signal the source device such as by pulling down a DC power node (e.g., shunting the node to cause a detectable change in the node voltage or the source current)
Data Source
AI summary
Apparatus and techniques described herein can include a load circuit comprising a direct current (DC) input terminal, and a source circuit comprising a direct current (DC) output terminal coupled to the DC input terminal of the load circuit. The source circuit can include a source control circuit configured to provide a current-limited DC output voltage and monitor the current-limited DC output voltage to detect an authentication signal provided at the DC output terminal by the load circuit, the load circuit configured to modulate the voltage at the DC output terminal using a pull-down circuit. The load circuit can be configured to compare the supply voltage at the DC input terminal to a reference voltage and, in response, energize other portions of the load circuit when the input current provided the DC input terminal is sufficient as indicated at least in part by the comparison.