Measurement of 4-Wire Voltage Sense on the LDC-3916 Laser Diode Controller
This technical note presents the results of voltage measurements on a typical laser diode control system, and highlights the advantage of the 4-wire voltage sense capability in the LDC-3916 and LDC-3700B Series Laser Diode Controllers.The measurement setup is shown in Figure 1. Typical cables were connected from the current source of an LDC-3916 Laser Diode Controller to a resistive load. A special adapter was made for the 9-pin connector on the LDC-3916, so voltages could be measured directly at the connector. The current source was set to drive a constant current through the load. Voltages were measured across the current source (V source), resistive load (V load), and voltage sense connections on the LDC-3916 connector (V sense). Cable lengths, resistor values, and current source setpoints were changed to measure different conditions.