Riverdi STM32 Evaluation Board User Manual Rev. 1.4
© 2021 Riverdi
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7.2.2
External
All the 10.1” (and rarely certain 7.0” displays) require external power supply for backlight, as the
backlight voltage exceeds 5V and power consumption is over the USB standard. To provide adequate
backlight power, set the jumper in P4 to lower position (it connects BL to EXT) – it must be placed in
lower position and connect the external DC voltage source to neighboring connector (“BL PWR”).
Refer to the picture and below.
Caution!
There is no reverse polarity protection on EXT_BL_PWR, incorrect connection will
damage the backlight permanently. Proceed carefully.
EVE4 BT817Q TFT series backlight power requirement summary:
Display size
Internal (from USB)
External
3.5”
OK
3.3V-6.0V (optional)
4.3”
OK
3.3V-6.0V (optional)
5.0”
OK
3.3V-6.0V (optional)
7.0”
Ok, if USB has 700mA min. efficiency
3.3V-6.0V (optional)
10.1”
External Power Only
5.0-14.0V (necessary)
