Dual-Mode Analog Front End for Isolated Two-Wire Metering
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Solution Overview
Problem
Current analog front end devices for poly-phase shunt power/energy metering require expensive isolators and separate communication protocols for isolated and non-isolated applications, increasing costs and complexity.
Innovation Solution
An analog front end device with a programmable ADC and a serial interface that can operate in both bidirectional and unidirectional two-wire modes, using a single clock and data output signal line, with internal clock generation and gain amplification, allowing for reduced pin count and flexible communication protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate front-ends are used for isolated and non-isolated applications, then device functionality is maintained, but cost and complexity increase
Solution Approach 1:
The patent implements a universal front-end device that can operate in both isolated and non-isolated applications through a single unified architecture. The device incorporates a dual-mode serial interface that can function as either a bidirectional interface (for non-isolated applications) or a unidirectional two-wire interface (for isolated applications), eliminating the need for separate front-end devices and reducing overall system complexity and cost.
Solution Approach 2:
The serial interface is designed with dynamic reconfigurability, allowing it to switch between bidirectional and unidirectional operating modes. This dynamic capability enables the same hardware to adapt to different application requirements (isolated vs. non-isolated), providing versatility without requiring multiple static device configurations.
2Adaptability or versatility
If bidirectional serial interface is used, then communication flexibility is maintained, but number of digital isolators increases
Solution Approach 1:
For isolated applications, the patent extracts the bidirectional communication requirement and implements only the essential unidirectional data transmission path. By removing the unnecessary bidirectional capability in isolated mode, the device reduces the number of digital isolators required from multiple isolators (for full bidirectional communication) to just one isolator for the unidirectional two-wire interface.
3Device complexity
If unidirectional two-wire interface is used, then cost is reduced, but programming capability is limited
Solution Approach 1:
The device incorporates preliminary configuration capabilities where programming can be performed during an initialization phase before the device enters its operational unidirectional two-wire mode. Configuration pins and registers allow the device to be programmed with operating parameters, gain settings, and other configuration data during setup, after which the device operates in the cost-effective unidirectional mode without requiring ongoing bidirectional communication for programming.
Data Source
AI summary
An analog front end (AFE) device has at least one programmable analog-to-digital converter (ADC) and a serial interface switchable to operate in a bidirectional serial interface mode and in a unidirectional two wire serial interface mode, wherein the unidirectional two wire serial interface mode only uses a clock input and a data output signal line, wherein the ADC operates in the unidirectional two wire serial interface mode synchronous with a clock supplied to the clock input.