Semiconductor Current Limit Circuit Using Multi-Function I/O Pins
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Solution Overview
Problem
Current limit circuits in semiconductor components increase the size and cost by utilizing additional input/output pins, which reduces performance and functionality.
Innovation Solution
A current limit circuit incorporating an integrated comparator and control portion connected to high and low side N-channel field effect transistors through control resistors, allowing current limiting without increasing the input/output pin count by using existing pins for multiple functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current limit circuit is included in a semiconductor component, then the semiconductor component is protected during over-current conditions, but the number of input/output pins increases
Solution Approach 1:
The patent applies multi-functionality by enabling existing input/output pins to serve dual purposes: normal signal transmission and current limiting function. The current limit circuit utilizes voltage drops across existing pins during over-current conditions to trigger protection without requiring additional dedicated pins, thus resolving the contradiction between reliability and device complexity
2Reliability
If a current limit circuit is included in a semiconductor component, then the semiconductor component is protected during over-current conditions, but the size of the semiconductor component increases
Solution Approach 1:
The current limit circuit is integrated into the existing semiconductor structure by utilizing voltage drops across existing pins and internal circuit elements. This approach allows the protection function to be embedded within the existing footprint without requiring additional external components or increasing the overall device size, thus resolving the contradiction between reliability and area
3Reliability
If a current limit circuit is included in a semiconductor component, then the semiconductor component is protected during over-current conditions, but the cost of the semiconductor component increases
Solution Approach 1:
The patent reduces manufacturing cost by eliminating the need for additional dedicated current limit pins and external components. The current limiting function is achieved through intelligent utilization of existing pins and internal voltage drops, reducing bill of materials costs and simplifying the manufacturing process while maintaining over-current protection capability
Data Source
AI summary
A semiconductor component that includes a current limit circuit and a method for limiting current in the semiconductor component. An input/output pin is connected to the gate of a transistor and a control resistor is connected between the gate of the transistor and its source. One terminal of the control resistor is connected to the input/output pin and the other terminal is connected to another input/output pin. A current source is connected to the input/output pin. A reference voltage is generated between the two input/output pins and compared with a drain-source voltage that is between one of the two input/output pins and another input/output pin. A control voltage is set in accordance with the comparison. The control voltage then controls the voltage on another of the pins that is not common to the reference voltage and to the drain-source voltage.