Fail-Safe Laser Diode Driver

Manufacturer:
MFG Part #:

IC-NZQFN28

Part #:
IC-NZQFN28
Availability:
In Stock
RoHS Status:
Unit Price:$6.53
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Minumum Qty: 1
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Product Information

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Three-channel laser diode pulse regulator iC-NZ enables the continuous wave operation of laser diodes and spike-free switching with defined current pulses in a frequency range of up to 155 MHz. The three channels can be accumulatively pulsed via inputs LENL, LENM and LENH. The peak optical power of the laser diodes is regulated separately for high, middle and low levels and adjusted using the three external resistors RMH, RMM and RML. The iC is activated via pin EN which triggers a selftest of the device. The system is enabled if no errors are detected. Any errors are signaled at pin NERR. The (average) current monitor can be set using external resistor RSI. Overcurrent is signalled at NERR, causing the iC to be shut down. To ensure that the selected laser class is maintained a second monitor input SMD (safety monitor diode) is needed. This optional photo diode monitors the laser power. Exceeding the monitor window, set-up by RSMD, triggers a permanent reset. This is reported at output NERR and can be deleted when the system is restarted at EN. For high pulse frequencies the device can be switched into controlled burst mode at input REGEN. A previously settled operating point is maintained throughout the burst phase. When the iC is switched on all safety-relevant signals pertinent to the current monitor, SMD and control unit are checked. These units are in turn monitored for the following: overcurrent, short circuits, open pins and whether the laser is switched off in terms of output power. With the exception of the latter these checks are carried out intermittently during operation. So that the device is single-failureproof various safety check routines are also implemented. To this end a second SMD (safety monitor diode) monitoring the laser power is required. The laser power must stay within a defined range during operation (thus maintaining the laser class). If this range is left, the system is shut down and an error message is generated.
 

Features

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Adjustable laser current monitor
All current LD types can be used (M/P/N configurations)
Autonomous safety circuit for a second photo diode monitoring the laser power
Error signal output at shutdown
Peak value controlled three level laser switch for operation from CW up to 155 MHz
Safety shutdown with overcurrent, overtemperature and undervoltage
Separate setting of laser power for each channel via external resistors
Single-failure-proof
Spike-free switching of laser currents of ca. 100 mA per channel (320 mA total) from 3.5 to 5 V supply voltage
Strong suppression of transients with very small external capacitors
System-enable with self test
 

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Fail-Safe Laser Diode Driver
Part #: IC-NZQFN28
Fail-Safe Laser Diode Driver