IC-HTP Datasheet, PDF (19/51 Pages) IC-Haus GmbH – DUAL CW P-TYPE LASER DIODE DRIVER

iC-HTP
DUAL CW P-TYPE
LASER
DIODE
DRIVER
preliminary
Rev B1, Page 19/51
Vref₀ is the minimum value (typically 0.1 V), ∆ Vref (%)
is the step value (typically 0.235 %) and n is the value
of REFx register in decimal.
Rsensex is 2kΩ when RACCx = 0 or 16kΩ when
RACCx = 1
current control through the 10 bit A/D converter. Reg-
ister bit ADFNSx must be set to 0 in order to measure
the internal sense node. An external monitor resistor
can be used to measure the optical power, achieved by
setting DISPx to 1. Therefore register bit ADFNSx must
be set to 1 in order to measure directly at pin MDKx.
MFACTx depends on several parameters as stated in
the following table:
ACC mirror factor
MERGE CRNGx
0
00
0
01
0
10
0
11
1
00
1
01
1
10
1
11
Mirror factor
Mirror Factor set to 2500
Mirror Factor set to 333
Mirror Factor set to 83
Mirror Factor set to 30
Mirror Factor set to 5000
Mirror Factor set to 666
Mirror Factor set to 166
Mirror Factor set to 60
Table 33: Mirror factor
10 Bit
D
A
8 Bit
D
A
+
-
CI
OVC
ECIE1
DCO
VBL1
CIH1
CI1
LDA1
ACC
VDD
MRH1
VB
CI1
..10 nF..
I LDA1
EM C
8 Bit
DISP1
R
0
255
APC
MDK1
x1
LDA1
P
10 Bit
A
D
VBL1
VB
A DM DK 1
x2
LASER CHANNEL 1 ^ADFNS1
Signal Level Converter
Table 34 shows some typical current settings. For de-
tailed limits, please refer to Electrical Characteristics
No. 114
Figure 8: ACC with monitor photodiode
ACC typical current settings
CRNG(1:0) REFx
RACCx=0 RACCx=1
00
0x000
125.3 mA 15.66 mA
00
0x001
125.6 mA 15.70 mA
00
0x010
125.9 mA 15.73 mA
...
...
...
00
0x200
416.6 mA 52.08 mA
00
0x201
417.6 mA 52.20 mA
00
0x202
418.6 mA 52.33 mA
...
...
...
00
0x3FD 1376.1 mA 172.01 mA
00
0x3FE 1379.3 mA 172.41 mA
00
0x3FF 1382.6 mA 172.82 mA
Table 34: ACC typical current settings
In ACC mode, the MDKx pin can be monitored through
a 10 bit A/D converter from 0 V up to 1.1 V. This can be
used for measuring the laser light power, if a photodi-
ode is connected to pin MDKx, as it is shown in figure 8.
This allows adjusting the voltage reference in order to
set the laser current and obtain the desired laser light
power.
The internal programmable logarithmic monitor Resistor
(PLR), if enabled (DISPx = 0), gives feedback for the
ACC mode permits combining both channels in one
iC-HTP (see chapter COMBINING BOTH CHANNELS)
and several iC-HTP in parallel. When both channels
are combined the programmable overcurrent shutdown
is carried out per each channel. If both channels are
configured in ACC mode, LDA1 and LDA2 can be con-
nected together. Each channel can be configured with
a different current range, yielding different granularity
in steps regulation for each channel.
The Regulator
In MCU mode the control can be carried out without
the need of external capacitor. This allows a fast re-
sponse of the regulator. The speed of the regulator’s
response and stability can be configured using three
bits (COMPx), providing a current compensation factor.
COMP1
000
...
111
Addr. 0x13; bit 6:4
R/W 011
Minimum compensation current for the channel 1
regulator, slower response
Maximum compensation current for the channel 1
regulator, faster response
Table 35: Current compensation channel 1