Electrostatic discharge self-protection circuit

Abstract

The invention discloses an electrostatic discharge self-protection circuit comprising a diode, a capacitor, a resistor, an OR gate circuit and an N-type driving tube. The OR gate circuit comprises at least two input ends and one output end. The anode of the diode is connected with an output welding pad, and the cathode of the diode is connected with a power supply. One end of the capacitor is connected with the power supply, and the other end is connected with one end of the resistor or one input end of the OR gate circuit. The other end of the resistor is grounded. The other input end of the OR gate circuit is connected with an internal circuit. The output end of the OR gate circuit is connected with the grid electrode of the N-type driving tube. According to the electrostatic discharge self-protection circuit, when an ESD current flows from the output end (IO) to a ground end (GND), the circuit always outputs a high electric potential to the grid electrode of the N-type driving tube. The N-type driving tube is started, and the ESD current is discharged via conduction of the N-type driving tube so that an effect of protecting the N-type driving tube is realized.

Description

technical field [0001] The invention relates to a semiconductor integrated circuit structure, in particular to an electrostatic discharge self-protection circuit. Background technique [0002] Such as figure 1 As shown, it is an electrostatic discharge (ESD) protection circuit commonly used as the protection of the output pad (IO) 13 at present. In the figure, a gate (gate) A of an NMOS (N_Driver, N-type drive transistor) 11 serving as a driving transistor is generally directly connected to an internal circuit 14 , and its potential is controlled by the internal circuit. Usually, an ESD NMOS 12 is connected in parallel with the N-type drive tube 11 for electrostatic protection. Generally, the trigger voltage of the N-type drive transistor 11 is required to be higher than the turn-on voltage of the ESDNMOS12, so that the ESD can be discharged through the ESD NMOS12 when ESD comes. This protection circuit has two disadvantages: one is that the potential at the gate A of the...

AI Technical Summary

Problems solved by technology

This protection circuit has two disadvantages: one is that the potential at the gate A of the N-type drive tube 11 is controlled by the internal circuit 14, and it may be at a high potential when the ESD current comes, which may cause the trigger voltage of the N-type drive tube 11 to lower than the turn-on voltage of the ESD NMOS12, figure 1 However, the protection circuit cannot play an ESD protection effect, and finally the N-type drive tube 11 is damaged before the ESD NMOS12; the second is that in some applications, the N-type drive tube 11 requires high operating voltage and low on-state resistance (Ron), which will reduce The breakdown voltage (BV) of the N-type drive tube 11 reduces the trigger voltage of the N-type drive tube 11 and reduces the design window of the ESD NMOS12

Images