ESD Protection Circuit With Bulk-Diode Path for Compact Layout
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Solution Overview
Problem
Conventional electrostatic discharge protection circuits require additional circuit elements and wasteful layout area to effectively manage voltage pulse states during electrostatic discharge events, limiting their protection capability.
Innovation Solution
An electrostatic discharge protection circuit comprising a first transistor, a second transistor, a capacitor, a voltage dividing circuit, and a diode, where the diode is formed between the bulk of the second transistor and a capacitor-resistor network, providing a bias voltage to the control terminal of the second transistor, allowing for efficient dissipation of electrostatic discharge current without additional layout requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional circuit elements are disposed to provide current dissipating path for different voltage pulse states, then electrostatic discharge protection capability is improved, but circuit layout area increases
Solution Approach 1:
The patent merges the functions of multiple circuit elements by forming a diode between the bulk of the second transistor and the capacitor-resistor network. This integrated structure provides both positive and negative voltage pulse protection pathways without requiring separate discrete components, thereby reducing layout area while maintaining comprehensive electrostatic discharge protection capability
Solution Approach 2:
The bulk of the second transistor serves multiple functions: it acts as the diode cathode for negative pulse protection, connects to the control terminal of the first transistor for current dissipation, and interfaces with the capacitor-resistor network for voltage division. This multi-functionality eliminates the need for additional dedicated components for different voltage pulse states
2Reliability
If circuit elements are disposed to respond to different voltage pulse states, then protection action is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple protection mechanisms into a unified circuit structure where the bulk of the second transistor integrates the diode function with the transistor control architecture. This merging reduces device complexity by eliminating redundant components while maintaining the ability to respond to both positive and negative voltage pulse states through the coordinated operation of the first and second transistors
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 enhances electrostatic discharge protection capability by providing a quick dissipating path for both positive and negative voltage pulses, reducing the circuit layout area and improving the reliability of integrated circuits.
Implementation Method 1
the diode may be formed through materials of a resistor (N-type) and a substrate (P-type) in an integrated circuit, and no additional layout arrangement is required
Data Source
AI summary
An electrostatic discharge (ESD) protection circuit includes a first transistor, a second transistor, a capacitor, a voltage dividing circuit, and a first diode. The first transistor is coupled between a first power rail and a second power rail. The second transistor is coupled between the first power rail and the second power rail. A bulk of the second transistor is coupled to a control terminal of the first transistor. The capacitor is coupled between the first power rail and a control terminal of the second transistor. The voltage dividing circuit is coupled between the control terminal of the second transistor and the second power rail, and has a divided voltage output terminal coupled to the bulk of the second transistor. The first diode is coupled between the divided voltage output terminal and the second power rail.