User manual

LPC3250 Developer’s Kit v2 - User’s Guide

Page 38

4.23 SP13: Power Supply

The power supply on the board is straight forward. There are three powering sources:

1. +5V DC via 2.1mm power jack (J24). Center pin positive. There is also an alternative

connector (J23) for this powering option.

2. USB powering via the USB-to-UART Bridge connector (J25).

3. +5V DC power form the PoE (Power-over-Ethernet) connector (J12).

In all cases, a stable +5V DC voltage powers the board. Current consumption depends on USB Host

usage. If USB Host is not used (or used with very low external current consumption), a 1 Amp power

supply (5W) is all what is needed. If USB Host is used with high external current consumption a 2-2.5

Amp power supply (10-12.5W) is needed.

The second powering option, via the USB-to-UART connector will work in most cases. Note however

that not all PC:s and laptops can provide this amount of current. An external USB Hub can be used in

that case or an external power supply.

U21 is a 1.5A +3.3V linear regulator. LED36 signals presence of regulated +3.3V. Three voltage

measurement pads exist for verifying correct voltage levels on the board. See picture below for

locating relevant components. The table below lists signal connections.

Figure 22 – Power Supply

Voltage Measuring Pads

Left-to-right:

GND, +5V, +3.3V

Power Supply Input

J24

Power Supply Input

J23

+3.3V LED

LED36

USB mini-B Connector

J25

PoE Connector

J12, pin 1 leftmost