Other Parts Discussed in Thread: TPS92640
Tool/software:
Hi TI expert team,
I have used the TPS92641 to develop a 6A LED driver with a shunt dimming function, and it works well. However, I have one question:
Should I use the TPS92640 or TPS92641 if I want to use an external gate driver for the shunt MOSFET?
Based on my experiment results, the integrated gate driver inside the TPS92641 for the shunt MOSFET has a longer delay time. To address this, I have used an external gate driver for the shunt MOSFET.
However, I noticed that if I send the shunt dimming control signal only to the external gate driver and not to the SDIM pin, the shunt dimming performance degrades, with some low-frequency noise.
On the other hand, when I send the shunt dimming control signal to both the SDIM pin and the external gate driver, the shunt dimming performance is perfect.
This leads me to believe that the internal circuit of the TPS92641 provides some compensation to the control circuit. I am concerned that if I use the TPS92640 for an LED driver with a shunt dimming function, the shunt dimming performance may be affected.
Thanks for your time. Any suggestion and opinions are appreciate.
Sean
