Cross-Coupled Differential Input Circuit for Below-Ground Bus Signals
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Solution Overview
Problem
Current engine control unit circuits are unable to accurately detect bus input signals with common mode voltages below ground without the use of bulky and complicated charge pumps or supply voltage converters.
Innovation Solution
A differential integrated input circuit using n-type and p-type semiconductor devices, where p-type devices are cross-coupled with n-type devices to maintain constant input current and handle both positive and negative common mode signals with a single supply voltage, eliminating the need for resistor dividers and external power supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a charge pump or supply voltage converter is used to handle common mode voltages below ground, then the circuit can detect bus input signals with voltages below ground, but the circuit becomes bulky and complicated
Solution Approach 1:
The patent extracts the charge pump or supply voltage converter from the circuit, eliminating the need for these bulky components. The differential integrated input circuit directly handles common mode voltages below ground through its differential amplifier architecture, removing the external power supply requirement and simplifying the overall circuit design.
Solution Approach 2:
The differential integrated input circuit is designed to universally handle both above-ground and below-ground common mode voltages within a single circuit architecture. The circuit can detect bus input signals across the full range of -10V to 15V without requiring different circuit configurations or additional power supplies, making it a multi-functional solution.
2Adaptability or versatility
If resistor dividers and external power supplies are used to handle below ground signals, then the circuit can process a wider voltage range, but the circuit area increases
Solution Approach 1:
The patent merges the functions of resistor dividers and external power supplies into the differential amplifier circuit itself. The differential amplifier directly processes differential voltage inputs and converts them to single-ended outputs within a single integrated circuit, eliminating the need for separate resistor divider networks and external power supply components, thereby reducing overall circuit area.
Solution Approach 2:
The differential integrated input circuit provides universal voltage range handling (-10V to 15V) through its inherent differential amplifier architecture, which can process both positive and negative common mode voltages without requiring additional components. This multi-functional design achieves wide voltage range capability while maintaining compact circuit area.
Data Source
AI summary
An apparatus, system, and method are provided for a differential integrated input circuit. The apparatus includes n-type semiconductor devices and p-type semiconductor devices. The p-type semiconductor devices are cross-coupled with the n-type semiconductor devices. Each of the p-type semiconductor devices biases a corresponding n-type semiconductor device.