ESD Protection Circuit with Diode Chain and Control Voltage Generator
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Solution Overview
Problem
Conventional electrostatic discharge protection circuits fail to effectively protect semiconductor integrated circuits from power noise, which can cause damage due to prolonged exposure to high voltage and current, and may malfunction when the number of diodes is reduced to protect against power noise, leading to inadequate protection during typical operation voltages.
Innovation Solution
An electrostatic discharge protection circuit that includes a diode chain coupled between a power supply voltage end and a control node, a control voltage generator to generate a control voltage based on current flowing through the diode chain, and a discharger to discharge current from the power supply voltage end to a ground voltage end, featuring P-well regions and resistors between diodes, enhancing sensitivity and discharge capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the number of diodes in the diode chain is reduced to respond to power noise, then the response speed improves, but the protection capability during typical operation voltages deteriorates
Solution Approach 1:
The protection circuit is segmented into multiple functional blocks: diode chain for voltage detection, control voltage generator for signal processing, and discharger for current discharge. This segmentation allows each block to be optimized independently - the diode chain uses fewer diodes for fast response while the control voltage generator compensates to maintain protection capability.
Solution Approach 2:
The patent changes the operating parameters by using a control voltage generator that amplifies the control voltage based on current flowing through the diode chain. This parameter change allows the circuit to maintain high protection capability even with fewer diodes, resolving the contradiction between response speed and protection capability.
2Reliability
If conventional electrostatic discharge protection circuits are used, then protection against electrostatic discharge is provided, but protection against power noise is insufficient
Solution Approach 1:
The protection circuit is designed with multi-functionality to handle both electrostatic discharge and power noise. The diode chain detects voltage abnormalities, the control voltage generator processes the detection signal, and the discharger responds to both types of threats, making the circuit universally protective against different voltage anomalies.
Solution Approach 2:
The circuit implements feedback through the control voltage generator that continuously monitors the current flowing through the diode chain and adjusts the control voltage accordingly. This feedback mechanism enables the circuit to adaptively respond to both electrostatic discharge and power noise conditions.
3Stability of the object's composition
If the diode chain uses more diodes for better voltage threshold control, then the voltage stability improves, but the sensitivity to slight voltage changes deteriorates
Solution Approach 1:
The control voltage generator acts as an intermediary between the diode chain and the discharger. It amplifies the control voltage based on the current through the diode chain, which compensates for the reduced sensitivity from using fewer diodes while maintaining voltage stability through controlled discharge.
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 circuit operates sensitively to slight changes in power supply voltage, effectively discharging current and stabilizing voltage within the integrated circuit's operation range, providing enhanced protection against both electrostatic discharge and power noise.
Implementation Method 1
When the diode 111 become conductive (i.e., conduct electric current) in response to approximately 0.7V applied therebetween, the diode chain 110 of FIG. 1 does not conduct electric current until the power supply voltage VDD exceeds a voltage equal to approximately 2.8V since four diodes 111 are serially coupled.
Implementation Method 2
The current flowing through the diodes 111 flows into the control resistor 120. Thus, voltage drop occurs between both ends of the control resistor 120 and accordingly, the voltage of the control node A is raised.
Implementation Method 3
when the voltages of the control node A increase to be higher than the ground voltage end 102 by a threshold voltage of the discharge transistor 130, the discharge transistor 130 is turned on.
Data Source
AI summary
An electrostatic discharge protection circuit includes a diode chain coupled between a power supply voltage end and a control node, a control voltage generator configured to generate a control voltage in response to a first current flowing through the diode chain, and a discharger configured to discharge a second current from the power supply voltage end to a ground voltage end in response to the control voltage, wherein the diode chain includes a plurality of P-well regions formed in an N-well region, diodes formed in the respective P-well regions, and a resistor coupled between the diodes.