Electrostatic Protection Circuit With Timed Noise-Resistant Discharge
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Solution Overview
Problem
The increasing integration of semiconductor circuits reduces voltage endurance capability, making chips susceptible to electrostatic discharge (ESD) damage, and existing electrostatic protection circuits are prone to false triggering by noise, affecting chip operation and increasing power consumption.
Innovation Solution
An electrostatic protection circuit with a turning-on circuit and a turning-off circuit controls the discharge transistor's operation through separate control signals, using trigger and processing circuits with tailored time constants and unidirectional conduction devices to prevent false triggering by noise and ensure complete electrostatic discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common electrostatic protection circuit is used, then electrostatic discharge protection is provided, but the circuit is prone to false triggering by noise
Solution Approach 1:
The protection circuit is divided into separate turning-on and turning-off control paths with different time constant configurations. The turning-on circuit uses a first resistor-capacitor circuit with a first time constant, while the turning-off circuit uses a second resistor-capacitor circuit with a second time constant that is greater than the first time constant. This segmentation allows differential response to noise versus genuine ESD events.
Solution Approach 2:
The circuit dynamically adjusts its response characteristics based on the timing and duration of the input signal. By using different time constants for turning-on and turning-off, the circuit adapts its sensitivity threshold, remaining insensitive to short noise pulses while responding to sustained ESD events that exceed the time threshold.
2Measurement precision
If the electrostatic protection circuit is made more sensitive to detect ESD events, then detection capability is improved, but false triggering by noise increases
Solution Approach 1:
The circuit performs preliminary timing analysis before triggering the discharge transistor. The turning-on circuit is configured to initiate discharge only after the input signal persists for a duration exceeding the first time constant, effectively filtering out sub-threshold noise pulses before they can cause false triggering.
Solution Approach 2:
The circuit changes the time constant parameter between the turning-on and turning-off phases. The first time constant controls the sensitivity for detecting ESD events, while the second time constant (greater than the first) controls the discharge duration and turning-off timing, creating a hysteresis effect that prevents noise-induced oscillations.
3Reliability
If the discharge transistor remains on for a longer duration to ensure complete electrostatic discharge, then discharge completeness is improved, but power consumption increases
Solution Approach 1:
The circuit uses a time-constant-based periodic control mechanism where the discharge transistor is activated for a specific duration determined by the second time constant of the turning-off circuit. This time-limited periodic discharge ensures complete ESD dissipation while automatically shutting off after the predetermined interval, preventing continuous power consumption.
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
The solution enhances the anti-interference ability and reliability of the electrostatic protection circuit, preventing false triggers and ensuring effective electrostatic discharge without interfering with normal chip operation.
Implementation Method 1
The trigger circuit may include a first resistor-capacitor circuit including a first resistor and a first capacitor concatenated between the electrostatic terminal and the low voltage terminal
Implementation Method 2
the discharge transistor may be configured to receive the first control signal at a first time, receive the second control signal at a second time, and perform electrostatic discharging between the first time and the second time
Data Source
AI summary
A circuit for electrostatic protection includes a turning-on circuit, a turning-off circuit, and a discharge transistor. The turning-on circuit is coupled to an electrostatic terminal and configured to generate a first control signal based on an electrostatic signal generated by the electrostatic terminal. The turning-off circuit is coupled to the turning-on circuit and configured to generate a second control signal based on the first control signal. The discharge transistor includes a control terminal, a first terminal, and a second terminal. The control terminal is coupled to both the turning-on circuit and the turning-off circuit. The first terminal is coupled to a low voltage terminal. The second terminal is coupled to the electrostatic terminal. The discharge transistor is configured to receive the first control signal at a first time, receive the second control signal at a second time, and perform electrostatic discharging between the first time the second and time.