Output Transistor Shutdown for Power-Line Disconnection Protection
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Solution Overview
Problem
Existing semiconductor devices fail to detect disconnections in power supply and ground lines, leading to abnormal currents due to current paths formed by transistor body diodes during disconnection, which can cause excessive current consumption and chip destruction.
Innovation Solution
A semiconductor device with a disconnection detection circuit that identifies disconnections in power supply and ground lines, using output transistor control circuits to interrupt current paths and transition to a power-off state, preventing abnormal currents by turning off output transistors when disconnections are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the semiconductor device uses output transistors with body diodes for normal operation, then the device can drive output terminals effectively, but abnormal current paths are formed when power supply or ground lines are disconnected
Solution Approach 1:
The disconnection detection circuit continuously monitors power supply and ground lines before abnormal current can cause damage. When disconnection is detected, the control circuit proactively turns off the output transistors to prevent abnormal current flow, rather than waiting for the harmful effect to manifest
Solution Approach 2:
The control circuit acts as an intermediary between the disconnection detection circuit and the output transistors. It receives detection signals and translates them into control signals that turn off the output transistors, mediating the response to prevent abnormal current while maintaining normal operation during healthy conditions
2Device complexity
If the device operates without disconnection detection capability, then the device structure remains simple, but the device cannot detect power supply or ground line disconnections leading to potential chip destruction
Solution Approach 1:
The disconnection detection circuit serves multiple functions: it detects both power supply line disconnections and ground line disconnections, controls both first and second output transistors, and provides fail-safe protection for the entire semiconductor device. This multi-functionality justifies the added complexity by delivering comprehensive protection
3Ease of operation
If no control mechanism is provided for output transistors during disconnection, then the device operates freely without control overhead, but excessive current consumption occurs due to body diode current paths
Solution Approach 1:
The disconnection detection circuit provides continuous feedback about the health of power supply and ground lines to the control circuit. This feedback loop enables the control circuit to adjust the state of output transistors accordingly - maintaining normal operation when healthy and turning off when disconnection is detected, thus preventing excessive current consumption
Data Source
AI summary
A first output transistor is connected between an output node connected to an output terminal and a ground terminal, and a second output transistor is connected between a power supply terminal and the output node. When disconnection of the ground terminal occurs, at least the first output transistor is turned off in response to a disconnection detection signal from a disconnection detection circuit, and a signal input to each circuit changes, causing a semiconductor device to transition to a power-off state.