Hot plug structure based on NMOS pull-up driver

Abstract

The invention discloses a hot plug structure based on an NMOS pull-up driver, and belongs to the field of integrated circuit I / O ports. An input end A is connected with an input end of a phase inverter INV1, and an output end of the phase inverter INV1 is simultaneously connected with a drain end of an NMOS transistor N1 and a gate end of an NMOS transistor N3; the drain end of the NMOS tube N3 is connected with a power supply VCC, and the source end of the NMOS tube N3 is connected with the drain end and the output end Y of the NMOS tube N4; the input end A is connected with the drain end of the NMOS tube N2 and the gate end of the NMOS tube N4, and the drain end of the NMOS tube N4 is connected with the source end and the output end Y of the NMOS tube N3; the output end Y is connected with one end of the resistor R1, the other end of the resistor R1 is connected with the drain end of the NMOS tube N5, the source end of the NMOS tube N5 is connected with the drain end of the NMOS tube N6 and the drain end of the NMOS tube N7 at the same time, and the drain ends of the NMOS tube N6 and the NMOS tube N7 serve as the substrate potential B of the NMOS tube N3. According to the invention, the isolation NMOS tube is used as the pull-up tube of the output stage, the port hot plug requirement of the driving stage can be realized through the substrate floating structure design of the NMOS, the pull-down driving capability of the output stage is enhanced, and in addition, the substrate bias effect of the pull-up NMOS tube is eliminated.

Description

technical field [0001] The invention relates to the technical field of integrated circuit I / O ports, in particular to a hot-swap structure based on an NMOS pull-up driver. Background technique [0002] With the rapid development of modern integrated circuit technology, more and more electronic products have entered our lives. In system-level application circuits, the buffer circuit connected to the bus is widely used, and the buffer circuit is often used as a function of level conversion or enhancing signal driving capability. In practical applications of large-scale communication circuit systems, these buffer circuits often choose to enter a sleep or power-off mode in consideration of actual work requirements. In another special case, when the buffer circuit is damaged and needs to be replaced, the system circuit is often not allowed to be powered off. This requires the buffer circuit to be plug-and-play. Therefore, the buffer circuit is required to have a hot-swappable ...

AI Technical Summary

Problems solved by technology

However, when the NMOS tube of this connection method is used as the output stage pull-up tube of the buffer circuit, the hot swap function of the circuit cannot be satisfied.

When the output port has a high-level pulse, the output port will flow back to the power supply through the integrated PN junction of the pull-up NMOS transistor substrate, thereby affecting the signal on the bus, and even the generated surge current will burn out the buffer circuit.

Images