FreeCalypso > hg > freecalypso-docs
changeset 74:e4eebf9ffce3
FC-handset-spec: Vf=2.9 V on both HaoRan and Formike LCD modules
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Thu, 16 Sep 2021 06:26:35 +0000 |
| parents | eb68975e1b81 |
| children | c458b7159fbd |
| files | FC-handset-spec |
| diffstat | 1 files changed, 3 insertions(+), 3 deletions(-) [+] |
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--- a/FC-handset-spec Thu Sep 16 00:08:00 2021 +0000 +++ b/FC-handset-spec Thu Sep 16 06:26:35 2021 +0000 @@ -208,9 +208,9 @@ LCD module where the 3 LEDs are joined at the anode, with the 3 cathodes brought out separately. LCD module datasheets call for 15 mA current through each LED at maximum intensity, for 45 mA total, and the LED forward drop voltage (Vf) at -this rated current seems to range between 2.9 V (what I actually measured on one -candidate LCD module) to 3.2 V (what the datasheets list as typical) to perhaps -as high as 3.4 V (what one datasheet lists as the maximum). +this rated current seems to range between 2.9 V (what I actually measured on +both Formike and HaoRan LCD modules) to 3.2 V (what the datasheets list as +typical) to perhaps as high as 3.4 V (what one datasheet lists as the maximum). Given the parallel (as opposed to series) wiring of the 3 LEDs and the relatively low Vf, there is no need to use any kind of boost converter as part