diff --git a/README.md b/README.md index 6127126..654dc64 100644 --- a/README.md +++ b/README.md @@ -82,10 +82,26 @@ through a MAX3232. The [desk case](case/README.md) is made for that board. ### Power -The display takes 5–24 V. At 5 V it draws about 0.8 A typical and 1.2 A -maximum, and the inrush current at power-on can be up to five times that. A -dev-board regulator can't supply this, so give the display its own supply, -for example 12 V at 1 A, and connect the grounds together. +The display takes 4.5–26 V. Its supply current with all dots lit (datasheet +section 4.6): + +| Supply | Typical | Maximum | Inrush at power-on (5 × max) | +|--------|---------|---------|------------------------------| +| 5 V | 0.8 A | 1.2 A | up to 6 A | +| 12 V | 0.35 A | 0.55 A | up to 2.75 A | +| 24 V | 0.2 A | 0.3 A | up to 1.5 A | + +The inrush current sets the size of the supply, not the running current. A +12 V 1 A adapter is **not enough**: it current-limits at power-on and the +display browns out during start-up. A dev-board regulator can't supply this +either, so give the display its own supply and connect the grounds together: + +- **12 V, 3 A or more** (recommended). The D1 R1 can share it through its + barrel jack, which accepts up to 12 V. +- **12 V, 2 A plus a bulk capacitor** of 2200 µF / 25 V or more across VCC and + GND at the display connector, so the capacitor supplies the inrush peak. +- **24 V, 2 A.** This has the lowest current, but don't feed it to the D1 R1's + barrel jack: power the board separately, e.g. over USB. ### Signal levels