IC-HTP Datasheet, PDF (14/51 Pages) IC-Haus GmbH – DUAL CW P-TYPE LASER DIODE DRIVER

iC-HTP
DUAL CW P-TYPE
LASER
DIODE
DRIVER
preliminary
ADFNS2
0
1
Addr. 0x1A; bit 6
R/W 0
ADC measurement PLR2 after level shifting (sense)
ADC measurement MDK2 pad (force)
Table 11: ADC channel 2 force/sense selection
10 Bit
D
A
EACC1
8 Bit
D
A
+
-
CI
OVC
DCO
ECIE1
VBL1
CIH1
CI1
LDA1
ACC
VDD
MRH1
VB
CI1
..10 nF..
I LDA1
EM C
8 Bit
DISP1
R
0
255
10 Bit
A
D
LDA1
VBL1
VB
A DM DK 1
LASER CHANNEL 1 ^ADFNS1
x1
x2
Signal Level Converter
APC
MDK1
RM1
P
Rev B1, Page 14/51
Two different control modes can be configured indepen-
dent for each channel: automatic power control (APC)
and automatic current control (ACC). In both modes
a 10 bit logarithmic D/A converter sets the reference
voltage and an 8 bit programmable D/A converter con-
figures the overcurrent threshold.
Figure 5: Channel 1 schematic
APC mode
In APC mode the laser power is controlled. The monitor
diode current (Imon) is used as feedback in the laser
power control loop. APC mode is selected by setting
EACCx register bit to 0.
EACC1
0
1
Addr. 0x10; bit 0
R/W 0
APC mode enabled for channel 1 (light power
regulation)
ACC mode enabled for channel 1 (laser current
regulation)
Table 12: Enable APC/ACC channel 1
8 Bit
D
A
10 Bit
D
A
+
-
CI
EM C
8 Bit
DISP1
R
0
255
x1
DCO
ECIE1
VBL1
CIH1
CI1
LDA1
VDD
MRH1
VB
CI1
..10 nF..
I LDA1
APC
MDK1
P
LASER CHANNEL 1
x2
Signal Level Converter
EACC2
0
1
Addr. 0x15; bit 0
R/W 0
APC mode enabled for channel 2 (light power
regulation)
ACC mode enabled for channel 2 (laser current
regulation)
Figure 6: APC mode simplified
Table 13: Enable APC/ACC channel 2
An example of APC with default configuration is shown
in figure 6.
An internal 8 bit programmable logarithmic monitor re-
sistor (PLR) can be used in APC mode. In APC mode
it is also possible to use an external monitor resistor
connected to pin MDKx. If the register bit DISPx is 0,
the PLR is present. If DISPx is 1, the PLR is disabled
and an external monitor resistor must be used.