High-swing programmable current source

Abstract

The invention discloses a high-swing programmable current source which comprises a reference circuit, a mirror image circuit and a protection circuit, wherein the reference circuit is composed of a first low-voltage PMOS (P-channel Metal Oxide Semiconductor) pipe and a first high-voltage PMOS pipe and a second high-voltage PMOS pipe; the mirror image circuit comprises a second low-voltage PMOS pipe, a third high-voltage PMOS pipe, a fourth high-voltage PMOS pipe, a fifth high-voltage PMOS pipe, a sixth high-voltage PMOS pipe and a seventh high-voltage PMOS pipe; and the protection circuit comprises an eighth high-voltage PMOS pipe and a ninth high-voltage PMOS pipe. The high-swing programmable current source provided by the invention has the advantages as follows: under the same mismatching and output impedance requirements, VdsBIAS drops greatly; secondly, the voltage Vdsswitch occupied by a switch originally can be saved; and thirdly, the high-voltage MOS pipe is used for protecting a low-voltage pipe at the voltages of Vds and Vgs of a clamping low-voltage current telescope. Therefore, the output swing of the current source is enhanced.

Description

technical field [0001] The invention belongs to a current source, and in particular relates to a high-swing amplitude programmable current source. Background technique [0002] In the field of high-voltage power supply, when a current source with adjustable current size and constant output current is required, the general implementation method is as follows: figure 1 Programmable current source circuit shown. First, a reference reference current is generated, and then through the current mirror, multiple mirror currents proportional to the reference reference current are generated. Through switch control, one or more mirror currents are selected to generate the required current. [0003] figure 2 It is a circuit diagram of the reference circuit 100 and the mirror circuit 101 of the existing programmable current source. The reference circuit 100 is composed of high-voltage PMOS transistors M1 and M2. The reference reference current IREF flows through the reference circui...

AI Technical Summary

Problems solved by technology

Analysis of the reasons: first, the threshold voltage of the high-voltage tube is larger than that of the low-voltage tube, and the saturation voltage drop Vds required by the high-voltage tube is larger when the same current accuracy and yield are satisfied; On the road, the voltage drop to consume

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