Low Power LIN Receiver With Single Comparator For Sleep Mode
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Solution Overview
Problem
Current LIN receivers require separate circuitry for silent/active and sleep modes, leading to high current consumption and limited functionality during sleep mode, as they cannot use voltage mode comparators due to excessive voltage ranges, which restricts full receiving capability.
Innovation Solution
A single, low-power LIN receiver structure with a single comparator that detects LIN signaling in both sleep and silent modes, using a current mirror circuit with hysteresis to maintain dominant and recessive levels at half the battery voltage, enabling full receiving capability during sleep mode with current consumption below 10 microamps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate dedicated blocs are used for silent mode and sleep mode functionality, then full receiving capability is available in silent mode, but current consumption exceeds requirements during sleep mode
Solution Approach 1:
The patent merges the silent mode receiver and sleep mode wake-up circuit into a single integrated structure. The same comparator circuit is used for both full receiving capability in silent mode and threshold detection in sleep mode, eliminating the need for separate dedicated blocs and reducing overall current consumption while maintaining full functionality in both modes
Solution Approach 2:
The comparator circuit is designed to serve multiple functions: it operates as a full LIN protocol receiver in silent mode with hysteresis for dominant/recessive level detection, and simultaneously serves as a wake-up detector in sleep mode by comparing LIN bus voltage to a threshold. This multi-functional design allows one circuit to replace what would traditionally require separate dedicated circuits
2Reliability
If voltage mode window comparator is used for LIN signaling detection, then full receiving capability is achieved, but overhead circuitry increases current consumption during sleep mode
Solution Approach 1:
The circuit dynamically adapts its operation mode based on the power state. In silent mode, the comparator operates with hysteresis for full LIN protocol reception. In sleep mode, the same circuit operates without hysteresis for simple wake-up detection. The circuit transitions between these operational states based on control signals, optimizing power consumption while maintaining receiving capability when needed
3Use of energy by moving object
If wake circuit comparator uses fixed detection level at 3.5-4V, then low power operation is achieved, but standard LIN levels at half battery voltage cannot be detected
Solution Approach 1:
The detection threshold parameter is changed based on operational mode. In sleep mode, a fixed low threshold (3.5-4V) is used for wake-up detection. In silent mode, the threshold dynamically adapts to half the battery voltage (Vbat/2) to properly detect standard LIN signaling levels. This parameter adaptation allows the same circuit to achieve both low power consumption and proper LIN signal detection across different operating states
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
The solution allows for low-power operation in both sleep and silent modes with full LIN receiving capability, reducing current consumption and eliminating the need for separate circuitry, thus enhancing power efficiency and cost-effectiveness.
Implementation Method 1
using a current mirror circuit with hysteresis to maintain dominant and recessive levels at half the battery voltage
Data Source
Figure 1~2A
Figure 2B
Figure 2C
AI summary
A LIN receiver includes a single, low power structure for both sleep and silent modes, with a single comparator for detecting LIN signaling during both sleep and silent modes as well as during active mode. In some embodiments, full receiving capability is implemented with a current as low as 5 microamps. In particular, dominant and recessive levels for the wakeup bloc are identical to those of standard LIN levels, fixed at about 3.5 V. Consequently, full LIN receiving capability is available during sleep mode.