1 Reply Latest reply on Aug 24, 2016 7:01 AM by user_242978793

    1550E NIR LED Driven with PSoC 5LP

    james.hayek

      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:

         

      https://www.thorlabs.com/drawings/7eb8aa50aa8195-42D7D857-5056-0103-79372B57193D06F2/LED1550E-SpecSheet.pdf

         

       

         

      Code: 

         
          #include <project.h>   
         
          int main()    
      {    
          CyGlobalIntEnable; /* Enable global interrupts. */   
         
              /* Place your initialization/startup code here (e.g. MyInst_Start()) */   
         
              Clock_Start();    
          PWM_NearIR_01_Start();    
          PWM_NearIR_02_Start();    
          PWM_LEDG_Start();    
          PWM_LEDR_Start();    
          PWM_IR_Start();    
          PGA_Start();    
             
             
             
             
             
          
             
             
            
         
              for(;;)    
          {    
              /* 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