Bootstrapped CMOS Line Protector for ESD and Miswiring Faults
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Solution Overview
Problem
Integrated circuits (ICs) are vulnerable to damage from excessive voltage due to electrostatic discharge (ESD) or miswiring, which existing protection methods fail to adequately address.
Innovation Solution
A line protector switch circuit comprising an external side switch, an internal side switch, a high supply circuit node, a low supply circuit node, and switch control circuitry that deactivates the internal side switch and diverts a small bias current to the low supply node when external voltage exceeds the high supply voltage, along with a bypass switch for quick recovery from transient faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing protection methods are used, then some protection from excessive voltage is provided, but adequate protection against ESD and miswiring is not achieved
Solution Approach 1:
The protection circuit is divided into two separate switches: an external side switch and an internal side switch. The external side switch handles voltage protection from external sources, while the internal side switch protects internal circuits. This segmentation allows each switch to be optimized for its specific protection role, achieving comprehensive protection against ESD and miswiring that single existing protection methods cannot provide.
2Stability of the object's composition
If the internal side switch remains active during excessive voltage, then circuit connection is maintained, but damage to internal circuits occurs
Solution Approach 1:
The switch control circuitry continuously monitors the external voltage and provides feedback control. When excessive voltage is detected, the control circuitry deactivates the internal side switch to prevent damage to internal circuits. This feedback mechanism ensures the internal side switch remains active during normal operation maintaining circuit connection stability, but automatically deactivates when harmful voltage levels are detected, preventing internal circuit damage.
3Device complexity
If a simple switch is used, then device complexity is reduced, but rapid recovery from transient faults cannot be achieved
Solution Approach 1:
The protection circuit uses dynamic control of the internal side switch through dedicated control circuitry. During transient fault events, the control circuitry rapidly deactivates the internal side switch to prevent damage, then quickly Reactivates it after the transient event passes. This dynamic on/off control provides rapid recovery from transient faults while maintaining a relatively simple overall device structure compared to more complex protection architectures.
Data Source
AI summary
A line protector circuit comprises an external side switch circuit coupled to an external circuit node of the line protector circuit, an internal side switch circuit coupled in series to the external side switch circuit and an internal circuit node of the line protector circuit, a high supply circuit node and a low supply circuit node, and switch control circuitry configured to deactivate the internal side switch circuit and divert a bias current from the external side switch to the low supply circuit node when the external voltage exceeds a high supply voltage of the high supply circuit node.