Single-chip ultra-high-voltage constant-current circuit

Abstract

The invention provides a single-chip ultra-high-voltage constant-current circuit, which comprises a high-voltage N-type DMOS (double diffusion metal oxide semiconductor) tube, a BJT (bipolar junction transistor) triode, a first resistor, a second resistor, a third resistor and a voltage stabilizing diode. Two ends of the first resistor are respectively connected with a grid electrode and a drain electrode of the high-voltage N-type DMOS tube, two ends of the second resistor are respectively connected with a source electrode of the high-voltage N-type DMOS tube and a base electrode of the BJT triode, two ends of the third resistor are respectively connected with the source electrode of the high-voltage N-type DMOS tube and an emitting electrode of the BJT triode, a negative electrode of the voltage stabilizing diode is connected with a collecting electrode of the BJT triode, a positive electrode of the voltage stabilizing diode is connected with the emitting electrode of the BJT triode, and the grid electrode of the high-voltage N-type DMOS tube is connected with the collecting electrode of the BJT triode. The single-chip ultra-high-voltage constant-current circuit is simple in structure, the technology of a hybrid integrated circuit consisting of double electrodes of a single chip, a CMOS (complementary metal oxide semiconductor) and a high-voltage DMOS is adopted, withstood voltage at a constant-current end can reach 700 volts, and requirements of various mains supply application schemes can be completely met.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a single-chip integrated ultra-high voltage constant current circuit based on the fabrication of bipolar, CMOS and DMOS devices on the same chip. Background technique [0002] In the analog circuit, it is necessary to provide a stable reference current for various amplifiers as the basis for ensuring the stable operation of the circuit. This reference current is a DC flow, which has little relationship with the power supply and process parameters, and has constant current characteristics. This constant current circuit with constant current characteristics is often used as a bias circuit and as an active load of an amplifier in an analog circuit. [0003] figure 1 It is a circuit structure diagram of an existing basic constant current circuit. It is characterized in that it uses an integrated op amp with high precision. The output end of the integrated op amp is connected to a...

AI Technical Summary

Problems solved by technology

figure 1 The disadvantages of the constant current circuit shown are: the circuit structure is complex; the withstand voltage value of the constant current terminal VA is subject to the limit value of the bipolar process, and the withstand voltage is less than 100 volts

Due to the factors of process discreteness and circuit structure, an external resistor at the IS terminal is required to adjust the constant current value, which is not conducive to mass production automation

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