ELM185xB Laser Diode Driver
■Application circuit example 1 (continuous drive circuit)
Circuit that laser diode is driven by constant output continuously. LDM, which is the combination of laser
diode (LD) and monitor diode (MD), is commonly used.
Based on various ways of handling poles and common pins, there are many different types of internal wire
of anode and cathode of LDM. Examples which LDM can be easily connected to ELM185xB are shown as
following three application circuits.
The fittest value of circuit constants will be different according to the used laser diode. Table 2 shows the
example when the forward current of laser diode is 35mA and monitor diode light current is 0.1μA.
circuit (1)
D2
MD
D1
LD
C2
LDM
V1
VCC
KLD
CMP
ILM
C1
R2
ELM185xB
AMD
GND
VR1
R1
circuit (2)
C2
D2
D1
LD
MD
V1
LDM
VCC
KLD
CMP
ILM
C1
R2
ELM185xB
AMD
GND
VR1
R1
circuit (3)
Tr1
Tr2
C2
D2
D1
LD
MD
V1
VCC
LDM
KLD
CMP
C1
ELM185xB
AMD
ILM
GND
VR1
R1
R2
10 - 5
ELM-TECH [ ELM Technology Corporation ]
