Koheron DRV200S User Manual

DRV200S - User Guide

Terminal block connections

VSI: Internal supply. Connect this pin to a 5V supply. Maximum current draw is 80 mA.

VSL: Laser supply. VSL can be set between 3 V and 19 V depending on the required compliance voltage.

Maximum current draw is equal to the laser current plus 20 mA. The laser supply is internally regulated with a
linear regulator where the output voltage V

SET

is defined by the VSET trimmer (see Adjusting the compliance

voltage section). The voltage drop in the linear regulator VSL - V

SET

must be kept above 0.5 V to ensure proper

voltage regulation and below 2 V to limit power consumption.

EN: Laser Enable pin. Apply a voltage between 2.2 V and 4.5 V to enable the laser current.

ISET: Laser current setpoint input. Apply a voltage at this pin to set the laser current. The input has 2 kΩ

impedance and is filtered by a second-order low-pass filter with 10 Hz cutoff frequency. Gain is 20 mA/V for the
DRV200S-A-40, 100 mA/V for the DRV200S-A-200 and 200 mA/V for the DRV200S-A-400.

IMON: Laser current monitoring pin. The voltage at this pin is proportional to the laser current. Gain is 50
mV/mA for the DRV200S-A-40, 10 mV/mA for the DRV200S-A-200 and 5 mV/mA for the DRV200S-A-400.
Output impedance is 1 kΩ.

LD+: Laser anode pin. Connect this pin to the laser anode.

LD-: Laser cathode pin. Connect this pin to the laser cathode.

RS: Do not connect.

Adjusting the compliance voltage

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The voltage V

SET

at the test point VSET must be set according to the laser operating voltage and current:

DRV200S-A-40 safe operating area

DRV200S-A-200 safe operating area

DRV200S-A-400 safe operating area

V

SET

can be adjusted between 2.4 V and 18 V with the VSET trimmer. When the board is powered off, adjust the

voltage V

SET

by using the formula V

SET

= R

SET

× I

SET

, where R

SET

is the resistance between GND and the VSET

testpoint and I

SET

= 100 µA for the DRV200-A-40 and the DRV200-A-200 and 200 µA for the DRV200-A-400.

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