Single-Wire Interface Protocol for PMIC State Synchronization
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Solution Overview
Problem
Modern semiconductor devices with multiple power domains face challenges in synchronizing device states across multiple power management integrated circuits (PMICs), particularly in power-up sequences, fault detection, and wake-up events, due to the complexity of managing multiple PMICs.
Innovation Solution
The implementation of a single-wire interface protocol using state synchronization circuitry in PMICs allows for the synchronization of device states between multiple devices. This protocol utilizes a single pin footprint for circuit design and supports any number of protocol commands for state transitions, including a heartbeat for fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multiple PMICs are used to manage multiple power domains, then thermal, circuit/layout and cost benefits are achieved, but device state synchronization complexity increases
Solution Approach 1:
The system divides the power management function into multiple independent PMICs, each managing specific power domains. This segmentation allows distributed thermal management and reduces the complexity of a single PMIC while maintaining synchronization through the single-wire interface protocol across all PMICs.
Solution Approach 2:
A single-wire interface protocol acts as an intermediary mechanism between multiple PMICs, enabling state synchronization without requiring complex multi-point communication infrastructure. The protocol uses simple pull-to-logic-value signaling with duration-based command encoding to coordinate operations across distributed PMICs.
2Device complexity
If a single-wire interface protocol is used for synchronization, then device complexity and circuit layout are simplified, but communication reliability must be maintained
Solution Approach 1:
The single-wire interface protocol serves multiple functions: state synchronization, command communication, and fault detection/heartbeat monitoring. By encoding different commands as distinct signal durations on a single wire, the system achieves reliable multi-purpose communication without requiring separate dedicated lines for each function.
Solution Approach 2:
The protocol incorporates heartbeat signals that allow PMICs to monitor each other's operational status and detect faults. This feedback mechanism ensures reliability by enabling devices to verify synchronization state and respond to failures, maintaining trust in the simplified single-wire communication channel.
3Productivity
If multiple protocol commands with different signal durations are used, then command encoding efficiency is improved, but timing precision requirements increase
Solution Approach 1:
The protocol uses periodic heartbeat signals and structured command sequences where signal durations are repeated or varied in predictable patterns. This periodic structure allows receivers to distinguish commands based on duration variations while maintaining timing robustness through expected periodic behavior, reducing the stringency of absolute timing precision requirements.
Data Source
AI summary
Example systems, apparatus, articles of manufacture, and methods are disclosed to implement a single-wire interface protocol to synchronize device states between multiple devices. Example logic circuitry disclosed herein for a first device includes transmit circuitry configured to pull a terminal of the first device to a first logic value for a first duration corresponding to a first command to be communicated via the terminal, wherein the first duration is one of a plurality of at least three possible durations corresponding respectively to a plurality of possible commands including the first command, and the plurality of possible commands is associated with device operation states synchronized between the first device and a second device coupled to the terminal. The example logic circuitry also includes receive circuitry configured to monitor the terminal.