Semiconductor IC Reverse Mounting Protection
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Solution Overview
Problem
Conventional semiconductor integrated circuit devices struggle to prevent breakage when reversely mounted due to unintended external conductor connections, especially when the number of external terminals is minimized, as in compact devices like polygon mirror motor driver ICs, where redundant terminals are avoided.
Innovation Solution
Incorporating a semiconductor integrated circuit device configuration with specific terminal connections and protective components, including an electrostatic protection diode and current control resistor, to divert excessive current and voltage away from critical terminals when reversely mounted, preventing breakage without additional redundant terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional protection methods (additional terminals or identification marks) are used, then reverse mounting protection is achieved, but the number of external terminals increases and mounting space increases
Solution Approach 1:
The patent combines reverse mounting protection functionality with existing necessary external terminals. Instead of adding redundant terminals, the invention makes existing terminals serve dual purposes: their primary function and reverse mounting protection function. This is achieved through internal circuit design where terminals are configured to provide protection when the device is incorrectly mounted, eliminating the need for additional protective terminals.
Solution Approach 2:
The invention makes existing external terminals multi-functional. Each terminal not only performs its designated signal or power function but also contributes to reverse mounting protection. The internal circuitry is designed so that when terminals are connected in the wrong orientation during reverse mounting, they automatically provide protection against damage, thus making the terminals universal in their functionality.
2Area of stationary object
If the number of external terminals is reduced, then mounting space is reduced, but reverse mounting protection becomes difficult to implement
Solution Approach 1:
The invention changes the electrical parameters (impedance, voltage levels, current paths) of existing terminals based on mounting orientation. When the device is correctly mounted, terminals operate with their normal parameters. When reversely mounted, the internal circuit configuration changes the electrical parameters automatically, causing terminals to enter a protection mode that prevents damage while maintaining the same physical terminal count.
Solution Approach 2:
The patent introduces internal circuit elements as intermediaries between the external terminals and the internal circuitry. These intermediary elements (such as protection circuits, impedance matching networks, or detection circuits) monitor the mounting orientation and activate protection mechanisms without requiring additional external terminals. The intermediaries enable the system to distinguish between correct and incorrect mounting orientations.
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
This configuration effectively prevents breakage during reverse mounting by managing current and voltage through the use of a Zener diode and current control resistor, ensuring the semiconductor integrated circuit device operates safely without redundant external terminals.
Implementation Method 1
an electrostatic protection diode an anode of which is connected to the third external terminal and a cathode of which is connected to the fourth external terminal
Implementation Method 2
a Zener diode an anode of which is connected to the third external terminal and a cathode of which is connected to another end of the current control resistor
Data Source
AI summary
A semiconductor integrated circuit device comprises a first terminal (denoted by VCC) connected to a power supply in a normally mounted state, a second terminal (denoted by SB) connected to a signal line in the normally mounted state and to a power supply in a reversely mounted state, a third terminal (denoted by SGND) connected to the ground in the normally mounted state, fourth terminals (denoted by HU−, HW−) connected to the signal line in the normally mounted state and to the ground in the reversely mounted state, electrostatic protective diodes (denoted by D1, D6) having anodes connected to the third terminal and cathodes connected to the fourth terminals and serving as means for protecting the fourth terminal in the normally mounted state, a current control resistor (R1) having one end connected to the second terminal and serving as means for preventing the second terminal from being broken in the reversely mounted state, a Zener diode (ZD) having an anode connected to the third terminal and a cathode connected to the other end of the current control resistor (R1). With this, destruction of the semiconductor integrated circuit device when it is reversely mounted onto a board or into a slot is prevented without providing any redundant external terminal.