IC-HK_1 Datasheet, PDF (2/13 Pages) IC-Haus GmbH – 155MHz LASER SWITCH

iC-HK
155MHz LASER SWITCH
Example 2: Switching between 50mA and 250mA
1. More than two current levels | both channels
are required
2. The lower DC current level of 50mA is
provided by channel 1 and the remaining
200mA pulse current by channel 2
3. As shown in Figure 4 (cf. data sheet, Figure
3), an RK2 value is selected for I(LDK) =
200mA and the corresponding voltage V(CI)
then determined - e.g. RK2 = 2S und V(CI) =
2.75V
4. Again as shown in Figure 4, the appropriate
value of RK1 is determined for I(LDK) =
50mA and V(CI) = 2.75V as RK1 = 20S
Rev 21.11.01, Page 2/13
Fig. 4: Determining V(Cl) for Example 2 and 3
Fig. 5: Signal patterns for Example 2
With the circuit shown in Figure 6, a voltage of 2.75V
at pin CI, RK1 = 20S, RK2 = 2S and EN1 = VDD the
laser current can be switched between typically 50mA
and 250mA by applying an appropriate pulse pattern
to EN2.
Fig. 6: Circuit with iC-HK for Example 2