LED1202 Can we use over 5V for VLED?

[YT_it]

Hello,

LED1202 Can we use over 5V for VLED?

For example, We plan to use  5V power supply. It's maximum voltage is 5.25V.

It is my understanding that we can use maximum VLED voltage is  VCS_MAX plus VF of used LED.

Is that right?

Thanks, 

[Peter BENSCH]

Correct is VCS_MIN + VF.

VCS is the so-called headroom voltage, which is required to control the LED. This is shown again in section 3.4 of the data sheet, which also mentions that two current sinks are implemented per LED channel. For the maximum LED current of 20mA, this results in a minimum headroom voltage of (approx.) 350mV.

In the data sheet, section 6.1. you can also see an example where VIN and VLED can be applied independently. This can even be tailored separately to the respective VF to maximise energy savings, so that VLEDr, VLEDg and VLEDb can be used for RGB LEDs, each with the appropriate voltage.

Does it answer your question?

Regards
/Peter

[YT_it]

Hello,

Thanks for your reply.

I understand that VCS is headroom voltage. VCS isn't allowable voltage value, is it?

Can we use 5.25V-5.5V VLED? When we can't prepare such 2.3V-4V VLED. 

Needless to say it is exept for energy savings or thermal problems.

Thanks, 

[Peter BENSCH]

Can you please upload a data sheet of an LED that has 5.25-5.5V, as I have never seen one except those with a built-in series resistor?

The headroom voltage VCS is at least 0.35V, so that a maximum differential voltage of 5.65V remains up to the maximum LED output voltage VCS0...VCS11 of 6V. As the headroom voltage increases, this differential voltage, which remains for the LED, inevitably decreases. Caution: this is the absolute maximum value because the voltage at the anodes of the LEDs must never exceed 6V.

Regards
/Peter

 

[YT_it]

We don’t plan to use the LED with a built-in series resistor.

I understand that the voltage at the anodes of the LEDs must never exceed 6V.

Thanks,