Bias Current Generation Circuit

Abstract

The present invention provides a bias current generation circuit, which includes a current steering DAC circuit and a current buffer circuit that buffers the current output by the current steering DAC circuit and outputs the bias current, and also includes an auxiliary circuit, the auxiliary The input of the circuit is connected to the two outputs of the current steering DAC circuit and is configured such that the voltages at the two outputs are approximately equal, the output of the auxiliary circuit is connected to one of the current buffer circuits Voltage bias terminal. The invention utilizes the auxiliary circuit to dynamically change the bias of the current buffer, thereby increasing the speed of establishing the output current of the current steering DAC circuit.

Description

technical field [0001] The invention relates to electronic circuits, in particular to a single-end output current steering DAC circuit. Background technique [0002] The current steering DAC circuit is often used to generate single-ended adjustable current as the bias of other circuit modules. In some applications, such as the laser tube driving circuit of the optical communication circuit, not only the adjustable current generated by the current steering DAC circuit is required as a bias, but also the adjustable current generated by it is required as a modulation signal. This requires the current generated by the DAC to be able to change rapidly over time. Due to the requirements of matching, the area of ​​the current-generating tube in the DAC is relatively large, and the influence of its parasitic capacitance is more obvious, which limits the rapid establishment of the DAC output signal. This phenomenon is particularly serious in the current steering DAC circuit compose...

AI Technical Summary

Problems solved by technology

[0003] In order to solve the technical problem that the output current of the current steering DAC circuit in the prior art cannot be quickly established, the present invention provides a bias current generating circuit, including a current steering DAC circuit and buffering the current output by the current steering DAC circuit and outputting the current buffer circuit of the bias current, further comprising an auxiliary circuit, the input end of the auxiliary circuit is connected to the two output ends of the current steering DAC circuit, and is configured such that the two output ends at the voltages are approximately equal, the output of the auxiliary circuit is connected to a voltage bias terminal of the current buffer circuit

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