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1550E NIR LED Driven with PSoC 5LP | Cypress Semiconductor

1550E NIR LED Driven with PSoC 5LP

Summary: 1 Reply, Latest post by bobgoar on 24 Aug 2016 07:01 AM PDT
Verified Answers: 0
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jameshayek's picture
3 posts

Hello all,

First time poster, first time project using a Cypress device. We would like to drive the 1550E LED from Thor Labs using the 5LP. We have sussessfully light up a Red LED using the following TopDesign: Please see the topDesign.JPG image attached. As well as code, please see code block below.

The data sheet for the 1550E LED is as follows:



#include <project.h>
int main()
    CyGlobalIntEnable; /* Enable global interrupts. */
    /* Place your initialization/startup code here (e.g. MyInst_Start()) */


        /* Place your application code here. */
/* [] END OF FILE */


Using the same code and topDesign we were able to light up the LED using a period of 100 and a CMP value of whatever we chose, in this case it was 15. We are using an 8 bit resolution and a UDB implementation with a 500 kHz clock cycle. The regular LED lights up just fine.

However, the Near Infrared LED doesn't seem to light up. Yes, we are aware the LED is not visible to the naked eye in that spectral range. However, we belived it was possible to check via a phone camera since it sees Infrared light. 

We were able to see the pulse we set in PSoC Creator via an oscilloscope but were unsuccessful in observing the current. We did observe the voltage on the input of the diode, so we know it was at least powered. In addition, the regular LED light up just fine.

The question:

Do we need a specific clock cycle, period and compare value to get a signal (light) to come out of this device that wasn't needed for the regular LED Diode?


Thanks in advance for your help,

James Hayek




user_242978793's picture
961 posts

"You are going to need an external transistor to drive this LED. As the current is 100 ma that exceeds the drive of the Psoc 5lp chip,

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