ESD Protection Circuit with Sustaining Control for Complete Discharge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrostatic discharge (ESD) protection circuits fail to completely discharge electrostatic signals within the required time interval, leading to increased voltages at terminals that can affect the normal operation of integrated devices.
Innovation Solution
The proposed ESD protection circuit comprises a transient detecting circuit, a level adjusting circuit, a discharging circuit, and a sustaining circuit, which work together to detect input signals, adjust output voltages, and control the discharging process to ensure complete discharge of electrostatic signals to a second pad, with the sustaining circuit prolonging the enablement of the discharging circuit to maintain low voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the discharging circuit uses a simple resistor-capacitor low pass filter configuration, then the circuit complexity is reduced, but the discharge time is insufficient and voltage cannot be completely discharged within the required time interval
Solution Approach 1:
The patent implements dynamic control of the discharging circuit by using a sustaining circuit that extends the discharge time based on detected voltage conditions. The circuit transitions from a static RC filter to a dynamically controlled system that adjusts discharge duration according to real-time voltage levels, ensuring complete discharge while maintaining reasonable circuit complexity.
Solution Approach 2:
The patent employs a feedback mechanism where the transient detecting circuit monitors the voltage at the first pad and provides feedback to the sustaining circuit. This feedback loop allows the system to detect when voltage discharge is incomplete and extend the discharge time accordingly, resolving the contradiction between simple circuit design and sufficient discharge duration.
2Productivity
If the NMOS transistor Mnb turns off after time interval Δt′, then the circuit returns to normal operation, but the voltage at terminal N1 increases greatly and electrostatic charge is not completely discharged
Solution Approach 1:
The patent implements preliminary action by having the transient detecting circuit continuously monitor voltage conditions and the sustaining circuit proactively extend the discharge time before the transistor turns off. This prevents incomplete discharge from occurring in the first place, ensuring reliability without sacrificing operation speed.
Solution Approach 2:
The sustaining circuit ensures continuity of the discharging action by extending the enablement of the discharging circuit beyond the original time interval Δt′. This maintains the useful discharge action until voltage is completely removed, preventing voltage spikes that would compromise reliability while allowing quick return to normal operation.
3Device complexity
If the voltage at terminal N1 increases after transistor Mnb turns off, then the circuit structure remains simple, but the normal operation of the integrated device is affected
Solution Approach 1:
The patent introduces a transient detecting circuit and sustaining circuit as intermediary elements between the simple RC filter and the discharging transistor. These intermediaries monitor voltage conditions and control the discharge timing, preventing harmful voltage increases while adding minimal complexity to the overall circuit structure.
Solution Approach 2:
The circuit implements self-service through the transient detecting circuit that automatically detects voltage conditions and triggers the sustaining circuit to extend discharge time when needed. This self-regulating mechanism prevents harmful voltage effects without requiring complex external control circuits.
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 solution effectively discharges electrostatic signals to acceptable low voltages, preventing voltage increases that could harm integrated devices by ensuring the discharging process is completed before the transistors turn off, thus maintaining normal device operation.
Implementation Method 1
a transient detecting circuit, coupled to a first pad for detecting an input signal at the first pad to generate a transient signal
Implementation Method 2
a discharging circuit, coupled to the first pad and the output terminal of the level adjusting circuit for discharging the input signal of the first pad to a second pad
Data Source
AI summary
An Electrostatic Discharge protection circuit, the circuit includes a transient detecting circuit, a level adjusting circuit, a discharging circuit, and a sustaining circuit. The transient detecting circuit is coupled to a first pad for detecting an input signal at the first pad to generate a transient signal; the level adjusting circuit is coupled to the transient detecting circuit for adjusting an output voltage at an output terminal of the level adjusting circuit; the discharging circuit is coupled to the first pad and the output terminal of the level adjusting circuit for discharging the input signal of the first pad to a second pad when enabled by the output voltage; and the sustaining circuit is coupled between the level adjusting circuit and the transient detecting circuit, for selectively controlling the level adjusting circuit to sustain an enablement of the discharging circuit according to the transient signal.