Source electrode follower based on PMOS transistor

Abstract

The invention provides a source electrode follower based on a PMOS transistor and belongs to the technical field of source electrode followers. The source electrode follower comprises a current source and the PMOS transistor used as an input component. A body end of the PMOS transistor is connected with an input end (Vin) of the source electrode follower, so that the voltage (Vsb) between a source electrode and a body end of an N trap NMOS transistor is basically kept stable under the condition that an input signal changes. The source electrode follower is small in distortion, good in linearity and especially suitable for being used in a high-speed heavy-load place.

Description

technical field [0001] The invention belongs to the technical field of source followers, and relates to source followers based on PMOS transistors. Background technique [0002] Source followers based on MOS devices (that is, MOSFETs, that is, MOS transistors) are widely used in various functional circuits. For example, the source follower can usually be used as a high-speed input buffer, its circuit structure is simple, the source follower can provide high input impedance, low output impedance and wide signal bandwidth; compared with the operational amplifier based on closed-loop drive, the source follower There are no stability issues with the device. Therefore, source followers are well suited for buffer and driver circuits. [0003] Figure 1 is a schematic diagram of a traditional PMOS transistor, where (a) is a schematic cross-sectional structure diagram, and (b) is a schematic diagram of an equivalent circuit. FIG. 2 is a schematic circuit diagram of a conventional ...

AI Technical Summary

Problems solved by technology

Since the PMOS transistors have gain Gain The characteristic that changes with the voltage of the output signal, that is, there is a voltage dependence. Therefore, the existing source follower based on the PMOS transistor is prone to large distortion when the input signal swing is large, so it is easy to linear distortion , poor linearity

[0007] And, since C sb 、C db and C b The existence of three parasitic capacitances can easily affect the high-frequency performance of the source follower based on the PMOS transistor. Therefore, when the source follower of the existing PMOS transistor is used in high-frequency or high-speed applications, it is easy to generate dynamic distortion

Images