Analysis and Design of the High-power Laser Diode Drive circuit Based on MAX797

摘要

According to the principle of the laser diode (LD) power supply, this paper uses the chip-MAX797 as a stabilized driven-current source to design the circuit. And the output current of the source can reach 4 A, its output voltage can be adjustable between 2.5V and 6V. The efficiency of the drive circuit is up to 96%, and the shutdown current is only 1 μA . Then make the necessary analysis about the design of the circuit. The whole circuit diagram is made up of three parts which there are an invariable driven-current source, a programmable soft-start circuit and a protection circuit of the over current and the restrained ripple. The adapter supplies the input voltage which is between 4.5V and 30V. And it adds a resistance to limit the current of the LD at last. The theory of this circuit's design is simple, and the function is as much as the conventional, but its size is smaller than the conventional driven-current source. Then summarize the advantages and disadvantages of the soft-start circuit between this paper and the traditional, and corresponding to analysis of the components selecting, it used the preferred components in the design of the circuit. Finally, there is a summary and expectation in high-power laser diode power supply design in the future.