Segmented Output Transistors for Fault Detection
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Solution Overview
Problem
Existing circuit apparatuses driving objects like motors lack an effective fault detection method, particularly for transistors with large channel widths, where crystal defects can cause faulty operations, and existing methods struggle to accurately detect such faults due to variability in transistor performance.
Innovation Solution
The circuit apparatus includes high-side and low-side transistors connected in parallel, with dedicated pads for each transistor to detect faults by measuring drain voltages, using a fault detection circuit that compares voltage differences between transistors, and employs a comparator with offset to enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If transistors with large channel width are used in the output circuit to provide sufficient drive capability, then the drive capability is improved, but the layout area increases and the risk of crystal defects increases
Solution Approach 1:
The patent divides the output circuit into multiple independent transistor units (first transistor, second transistor, third transistor, fourth transistor) instead of using a single large transistor. This segmentation allows the circuit to maintain sufficient drive capability through parallel operation while reducing the channel width of each individual transistor, thereby lowering the probability of crystal defects in each unit.
2Power
If transistors with large channel width are used to provide sufficient drive capability, then the drive capability is improved, but the layout area increases
Solution Approach 1:
The patent segments the output circuit into multiple smaller transistor units that can be arranged in a more compact configuration. By using multiple transistors with smaller individual channel widths rather than one large transistor, the layout area is optimized while maintaining the required drive capability through parallel operation.
Solution Approach 2:
The patent combines multiple transistor units (first, second, third, and fourth transistors) to work together in parallel, achieving the cumulative drive capability of a large transistor while using smaller individual components that occupy less total layout area and can be more efficiently packaged.
3Reliability
If existing fault detection methods are used, then fault detection is attempted, but the detection accuracy is insufficient for transistors with large channel widths
Solution Approach 1:
The patent segments the fault detection process by providing separate detection circuits and terminals for each transistor unit. The first detection circuit detects faults in the first and second transistors, while the second detection circuit detects faults in the third and fourth transistors. This segmented detection approach improves measurement precision by isolating individual transistor faults rather than attempting to detect faults in a single large transistor.
Solution Approach 2:
The patent introduces intermediate detection terminals (first detection terminal, second detection terminal, third detection terminal, fourth detection terminal) that serve as intermediaries between the transistor units and the detection circuits. These terminals enable precise measurement of each transistor's state, improving detection accuracy through dedicated measurement points.
Data Source
AI summary
An output transistor of an output circuit that outputs a large current may have a partial fault, but such a partial fault may not be detected because the transistor is very large. To address this, the invention provides an output circuit in which one output transistor is divided into a plurality of transistors, and a plurality of pads that are connected correspondingly to the transistors are provided. Fault detection can be performed on the plurality of transistors by using each pad. At least some of the pads are connected to one same output terminal of the substrate or the like.