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@Audioguru
Not sure why you are saying that.
If you read my first post, I am using 2N7002P,215.
Looking at the datasheet, it has Gate-Source threshold 1.75 (2.4V Max)
Am I missing something?
https://assets.nexperia.com/documents/data-sheet/2N7002P.pdf
Thank you everyone for replies.
From what I see, there is a very little brightness difference between 25mA and 30mA.
I will add 7 Ohm resistor plus Rds
That should have about 0.3V drop and limit the current.
I also changed PWM to ~1 KHz and I don't see any difference - thank you for the tip.
Just a sanity check:
If I have an LED that is listed 3.3V x 30mA, can I safely connect it directly (no resistor or MOSFET) to a 3.3V power supply and expect 30mA current draw?
Thanks
Thank you for your patience with me.
Here is what I got:
- 3.3V 30mA backlight,
- Zero Ohm drain resistor
- PWM is set to 0.80 duty cycle, 66 KHz Frequency
Measuring current 29.95 mA (calibrated DMM)
From this point, I can gradually reduce PW and current proportionally going down.
Few...
I am sorry, I did not provide enough information.
Unfortunately I don't know if it can tolerate 3.45V on the backlight side.
Display is off-brand TFT177F254FPC based on ST7735S driver
It's similar to this:
https://www.adafruit.com/product/618
I have few variations from different vendors and...
Hi everybody, need little help.
I have a small 1.77" TFT LCD that uses 3.2V / 20mA backlight that I want to have a variable brightness.
Circuit controlled by PIC18F26K40 and n-channel MOSFET 2N7002 (2N7002P,215 Nexperia) with Rds On = 1.6 Ohm.
Device power is regulated 3.45V (can't be changed)...
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