This paper attempts to describe a laser diode driver circuit using the depletion mode gallium nitride high electron mobility transistor (D-mode GaN HEMT) to generate nanosecond pulses at a repetition rate up to 10 MHz from the vertical-cavity surface-emitting laser (VCSEL). ROHM offers laser diodes (LDs) for Light Detection and Ranging (LiDAR). This application note will introduce ROHM's LD line-up and show how to design the drive circuits of ROHM LDs. With the popularity of near infrared (IR) wavelength. Gallium nitride (GaN) power FETs and ICs have demonstrated order-of-magnitude improvements in performance figures-of-merit over silicon MOSFETs while achieving cost parity to silicon on an equal voltage and RDS(on) basis. The key improvements are increased switching speed and decreased size. This article demonstrates basic circuits for pulsing infrared LEDs and low power visible semiconductor lasers using components which are inexpensive and fairly readily available.
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