IC-HG_13 Datasheet, PDF (10/20 Pages) IC-Haus GmbH – 3 A LASER SWITCH

iC-HG
3 A LASER SWITCH
LASER OUTPUTS LDK1...6
Rev B1, Page 10/20
LDK1...6 are the current outputs for the laser diode
cathode. For high speed operation, connect the laser
diode as close as possible to this pins to minimize the
inductance. To ensure a high switching speed, it is
important to minimise the inductance of the whole cur-
rent loop (cf. Figure 7, marked red) consisting of iC-
HG (pins LDKx and AGNDx), the laser diode (anode
and cathode), the backup capacitors as well as the en-
closed area. It may still be necessary though to use an
R/C snubber network for damping L/C oscillations.
Depending on the residual inductance in the laser
current path and the actual laser current, fast free-
wheeling diodes from LDKx to VLDA may be required
(cf. Figure 8, diode D1) to protect the outputs. The an-
ode of the free-wheeling diode should be close to the
to be protected LDKx output and the cathode close to
the backup capacitors at VLDA for the free-wheeling
current to be dumped into, when switching the respec-
tive channel off.
..12V
CLDA1
100μF
CLDA2
10μF
CLDA3
100nF
CLDA4
10nF
CLDA1
100μF
CLDA2
10μF
CLDA3
100nF
CLDA4
10nF
3..5.5V
CVDD2
100nF
iC-HG
VDD
CVDD3
10nF
CVDD1
10μF
CVDD2
100nF
LD1
iC-HG
VDD
LDK1
CVDD3
10nF
D1
LD1
LDK1
CI1
CI1
CI1
EN1
+
-
CI2
EN2
ENTTL1
&
AGND1
LDK2
CI2
Figure 7: Current loop
ENTTL2
&
AGND2
EN1
LD2
CI2
EN2
+
-
LD3
&
AGND1
LDK2
Figure 8: Free-wheeling diode
&
AGND2
LD2
LD3
CI3
EN3
CI4
EN4
CI5
EN5
CI6
EN6
6
F
ELVDS
CI3
PULSED _EO_NTTP_L3ERATION
LDK3
AGND3
CI3
EN3
LD4
LDK3
AGND3
LDK4
CI4
CI4
LDK4
AGND4
EN4
The curren^ENt^TTf^Lo⁴ r pulsed operation may be higher than
for CW operCaI5tion. Therefore th^Le^DK5RMS current of^CIt⁵he
AGND4
With I_CWmax ^Lf^Dr⁵om Electrical Characteristics No. 101 and
pulses < 10 µs. So for a single c^LDh^K5annel operated with
pulse train has ENTTL5 to be considered^A.^GND5
EN5
a 50% duty cycle^L,^D6the max. laser^AGc^NDu⁵ rrent becomes
LDK6
CI6
CI6
LDK6
VDD
80%
ENTTL6
CI1
CI2
I = I · ^10nF
10nF
pulsemax
CWmax
AGND6
RNER
repetition time(T ) ^CI3
10nF
CI4
N¹⁰EⁿR^F
CI5 ^10K CI6
10nF
10nF
pulse time(t ) ^NERROR
EN6
(1) ^VDD
80%
AGND6
√ NER
I_pulsemax = 500 mA · 2 = 707 mA
RNER
10K
NERROR
60%
ELVDS
60%
40%
Power &
ANALOG
20%
GROUND^TMS^emonpiteA_orratuG^re ND1...6
40%
20%
Power &
Temperature
Monitor
GND
GND
AGND1...6 are the ground pins for the channels. It is
recommended to connect all AGND1...6 pins to GND.
ERROR OUTPUT NER
The open drain pin NER is a low-active error output.
Signalled errors are ELVDS open or at 50% VDD, VDD
undervoltage and thermal shutdown.