TPS92630-Q1: dimming in/out issue

qinlei

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

over 2 years ago

0 Pedro Arango Ramirez over 2 years ago

TI__Expert 4970 points

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.

0 qinlei over 2 years ago in reply to Pedro Arango Ramirez

Intellectual 430 points

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?

0 Pedro Arango Ramirez over 2 years ago in reply to qinlei

TI__Expert 4970 points

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

0 qinlei over 2 years ago in reply to Pedro Arango Ramirez

Intellectual 430 points

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

0 Pedro Arango Ramirez over 2 years ago in reply to qinlei

TI__Expert 4970 points

Hello Qinlei,

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

Best,

Pedro Arango Ramirez

0 Pedro Arango Ramirez over 2 years ago in reply to Pedro Arango Ramirez

TI__Expert 4970 points

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

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TPS92630-Q1: dimming in/out issue