Hi team,
I have a question about the TLC5926 operation at low currents. I have to propose a solution that have to smoothly and slowly start up multiple channels of WLEDs. Linearity and accuracy on low currents(<10mA) is not a problem but the system have to start smoothly.
This device have the lowest current gain 1/12. This means that for a system with Imax = 120mA, the lowest current possible is approx. 10mA. So, our starting point will be 10mA.
To reduce starting current I want to propose to parallel 2 outputs to a one LED string. In this case we start with 5mA than we increase the cusrrent up to 60mA, and reduce the global gain to 30mA and in the same time enable second channel (30*2 - 60mA), and continue to increase current up to 120mA.
First question: is it allowed to parallel channels of TLC5926?
The second solution is to control the reference resistance by this schematic:
The idea is to startup with the only R5 as the reference and in a some moment connect add R4 in parallel to R5 by MOSFET. This will increase a reference current and as consequence LED current. In the moment time the current gain will be recalculated and updated by digital interface.
Second question: is it allowed to change the reference resistor of TLC5926 "on the fly"?
