LDPC Diode Driver
The LDPC series laser diode drivers offer the laser de- signer a compact low cost power supply for a variety of medical and industrial applications. In order to take full advantage of this unique product, care must be taken during the design process to ensure long term reliabilty. This data sheet includes answers to many commonly asked questions about the various configurations avail- able and includes critial cooling and electrical informa-tion.
Maximum Output Power:
Maximum Output Current:
0.2% at maximum output current
0.5% at maximum output current
<1% of maximum output current
Limited to Maximum power with Fold Back Circuit
Rise / Fall Time:
3-20µs. Depending upon output voltage
Inhibit / Enable:
5V to 15V to enable output
0 to 10V = 0 to full current
0 to 10V = 0 to full current
0 to 10V = 0 to full voltage1
Power supply Protection:
Reverse Input voltage, input overvoltage, over temp
Laser Diode Protection:
Control rise / fall times, no overshoot
68.75mm x 150mm x 45mm high
0 to 40 ° C, 90% RH non condensing
See page 3 for fan size and mounting instructions
1. If maximum compliance voltage is less than 10V, Vout Monitor will read output voltage directly. If maximum compliance voltage is greater than 10V, then Vout Monitor will be scaled such that 0-10V = 0-Voutmax.
2. Proper cooling is required for reliable operation. See page 3 for correct fan placement and other cooling recommentations.
Maximum Output Ratings
The LDPC laser diode drivers are available in two power levels. Mod- els to ~ 100watts (50amps) can be operated from 12 or 15 volts while power levels up to 225 watts require 24VDC input. The table to the right details typical input voltages and currents when the units are run at maximum output current for their particular power rating. The LDPC power supplies can be ordered with any output voltage and current as long as you do not exceed the maxi- mum parameters listed.
OutputV @ Max current
2V @ 50A
4V @ 40A
6V @ 37A
10V @ 22.5A
16V @ 14A
12VDC / 15VDC input
2.38V @ 50A
11.6A / 15Vin
2.38V @ 50A
14.9A / 12Vin
Part Number Example: LDPC-10-6-12 = 10amps, 6 volts output, 12VDC input
2) scale for various output The LDPC interface is a simplified version of the LDD series controls utilizing the same analog 10 volt programming. The connector is a 6 pin right angle board mounted Molex # 22-05-3061. Their are several options for the mating connector (not included) but a suitable part number is the 22-01-2067. Note Vmon. (pin 2) scale for various output voltages.
5 to 15V = Enable Output, Default OFF
1 to 1 for Vout ≤ 10V
0 to 10V = 0 to full scale for V> 10V
TTL High = ON, Default = High
0 to 10V = 0 to Full scale
N / A
0 to 10V = 0 to Full Scale
1. Input Connector: .25 ”male Quick Connects.
Note: Input current cannot exceed 15 amps.
2. Interface Connector: Molex # 22-05-3061.
3. Fan Output: J1 (Molex # 26-60-4020) output is
equal to the input voltage for 12 or 24 volts input.
For 15 VDC input J1 = 12 V.
4. Output Connectors: 6 x 32 Screws. See outline
drawing below for location.
≥30cfm, 60mm x 60mm fan Recommended Fan: ≥30cfm, 60mm x 60mm fan
Larger dimentional fans of equal output will not concentrate the airflow to adaquately cool this product. Note: Larger dimentional fans of equal output will not concentrate the airflow to adaquately cool this product.
Proper cooling of the LDPC board is critical to the operation and reliability of the product. The diagram above shows the fan position and required airflow for safe operation. The fan must be positioned as shown in diagram above. Mount fan .25 ”from board for proper cooling. Note: Failure to properly cool the board using the correct size and position of the fans may result in thermal shutdown and potential catastrophic damage to the power supply. Damage to the board from inadequate cooling is not covered under warranty.
The LDPC supplies are primarily designed for CW operation but have a very short rise / fall time and are easily pulsed using pulse pin (# 3) on the inter face connector. Figure is a scope trace of a 50 amp 2 volt pulse with a rise / fall time of 2.2µs. The chart below shows typical compliance voltage / rise time values.
Rise / fall time
If you are using this product for the first time please read and follow the following procedures:
1. Unpack module and position the device on a flat surface with the heat sinks up. The LDPC module will not cool properly when mounted upside down (heatsinks down). Locate proper size fan as outlined on page 3. (Consult customer service for proper vertical mounting and cooling).
2. To protect you laser diode from damage it is recommended that you apply a dummy load to the output of the LDPC module during tests. A standard “fast recovery” diode or series string of these diodes that approximately matches the voltage drop of your laser diode should be used for testing.
3. Connect your current monitoring device to the current monitor output pin 6 on the interface connector. A digital voltage meter set to 0 to 10V for CW operation or a scope for puled operation. Connect a 0 to 10V program voltage to the current program input pin 4. Optional: you can monitor compliance voltage at the voltage monitor output pin 2. Install jumper JPI for pulsed opeation or a TTL pulse source for QCW.
4. Apply DC input voltage, apply a signal to enable pin 1 and adjust current program voltage to desired output current. Moni- tor output current with monitoring device. See interface description, page 2 for input and output voltages.
5. For pulsed operation connect pulse pin 3 to a pulse signal.
Note: Grounding the negative output of the module may cause ground loops and excessive noise.