Digital adjustable constant current drive circuit

Abstract

The invention relates to a digital adjustable constant-current driving circuit comprising a reference current source module, a constant-current adjusting module, a buffer, a constant-current output stage module, a current control bit module, first reference voltage, second reference voltage, and an external resistor. The reference current source module is connected with the first reference voltage, the constant-current adjusting module, and the external resistor. The constant-current adjusting module is connected with the buffer and the second reference voltage. The buffer is connected with the constant-current output stage module. The constant-current output stage module is connected with the current control bit module and comprises a plurality of same constant-current output channels. The second power tubes in the constant-current output channels are divided into a plurality of groups. The connection and disconnection of each group is controlled by a current bit. The number of connected power tubes is changed by an external write current control bit and thus the mirror image proportion of a current mirror formed by a first power tube and a second power tube is adjusted. As a result, a purpose of adjusting a constant-current output value is achieved.

Description

technical field [0001] The invention relates to an electronic circuit, in particular to a digital adjustable constant current drive circuit. Background technique [0002] With the rapid development of the economy, the demand for information display planes in modern life is increasing day by day. In particular, the use of LED display screens has increased dramatically due to their advantages such as low cost, high brightness, and wide viewing angles. The use of the LED display is inseparable from the driver chip it needs. The controllable current can be obtained through the driver chip to realize the display of LED with different brightness and meet various application occasions. However, people have higher and higher performance requirements for LED displays, which requires LED driver chips with better performance to achieve better performance. [0003] The traditional LED driver chip adopts a 16-channel constant current output structure, and the constant current output va...

AI Technical Summary

Problems solved by technology

[0005] The present invention is designed for the disadvantage that the traditional LED constant current drive chip is not easy to adjust the output current value, and adopts the following technical scheme: a digitally adjustable constant current drive circuit, including a reference current source module, a constant current adjustment module, a buffer, a constant Current output stage module, current control bit module, first reference voltage, second reference voltage and external resistor; the reference current source module is connected to the first reference voltage, constant current adjustment module and external resistor, and the constant current adjustment module is connected to the buffer and the second Two reference voltages, the buffer is connected to the constant current output stage module, and the constant current output stage module is connected to the current control bit module

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