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TPS92630-Q1: dimming in/out issue

Part Number: TPS92630-Q1

hello, i have one  question about the TPS92630 ic,  i would like to achieve the LED dimming in/out , i think i need to apply the PWM control ,  I will adjust the PWM duty cycle from 0 to 100% to achieve LED breathing effect,Different time periods correspond to different duty cycles , Can I use it this way? Will there be any issues? My project is currently in the testing phase and I am concerned about any issues that may arise,so please help check this .

thank you 

best regards 

  • Hello Qinlei, 

    What you are describing is a good use of this device. You would be using the PWM dimming to vary the brightness of the LEDs. The following schematic in the datasheet is a good starting point: 

    This way you can control each channel independently. I can't guarantee if your design will function without taking a look at the schematic first. 

    Best,

    Pedro Arango Ramirez. 

  • hello I think there will be some issue,I heard that when the pwm duty is low,maybe led short been decteced,could you help explain this?

  • Hello Qinlei, 

    As I said in my previous response, I can't guarantee the function unless I can see the schematic of the whole design and the parameters at which you want to run the system at. 

    • Duty Cycle Range
    • Duty Cycle Frequency
    • Input Voltage
    • Output Voltage
    • Number of LEDs
    • Desired output current

    Please provide me with more information as I can not assist without it. 


    Best,

    Pedro Arango Ramirez

  • Hello,i am sorry that i am late , please refer to the above picture

    and i provide the following information :

    • Duty Cycle Range :0-100%
    • Duty Cycle Frequency 500KHZ
    • Input Voltage :8.5V
    • Output Voltage : 5.2V-6.8V
    • Number of LEDs: Per channel 3*10  (LED Matrix )
    • Desired output current :Per channel 60mA

    i need to achieve the animation :dimming in/out ,so the PWM duty will change from 0-100%  to achieve LED breathing,please help check this.

    Thank you 

    Best regards 

  • Hello Qinlei, 

    Allow me to look over this. Expect a response in the next 48 hours. 

    Best,


    Pedro Arango Ramirez

  • Hello Qinlei,

    Thank you for sharing your schematics. 

    Overall I believe that the design should work, though I would like to note some caveats

    • As it stands you are not using the current regulation feature, if you want to set a maximum current allowable this should be done. 
    • Make sure to look at the timing diagrams of the PWM cycles, if the frequency is higher than the slew rate, then cycles might not be detected and you might have some false alarms. 
    • Make sure that your input voltage is enough to sustain the device dropout at the desired current level as well as the LED voltage drop. 

    Best,

    Pedro Arango Ramirez