Test power supply circuit of SAM laser two-plate tube

This is a basic laser power supply that uses a pair of ICs as regulators to provide a variable voltage within the adjustable current region to meet the safe current adjustable region. This solution is better than forcing the use of a pair of regulators - one for voltage regulation and the other for current limiting.

　　The idea is to be able to safely test a laser diode, or to ensure that the initial current is limited to a safe value to complete the drive, ensuring that the entire circuit is working properly and/or the laser diode operating state can be fully determined. This can replace an expensive laboratory power supply to test low-power laser devices.

　　This circuit is shown in SAM's Laser Diode Test Power Supply I (SC_LTl)r. As shown in the figure, the appropriate laser diode requires a current of approximately 25mA~250

　　By making some changes to some parts of the circuit, the same circuit can be suitable for currents up to 1A or more.

　　More modern lower dropout regulators like the LT1084 can be used instead of the LM317. For continuous load currents exceeding 100 mA, a heat sink is required on the IC regulator.

　　An additional voltmeter placed in the knob position is also acceptable, and a potentiometer with the correct voltage adjustment to correct the voltage to maintain the current limit is of course better.