Hardware Setup
6
SNVU495 – March 2016
Copyright © 2016, Texas Instruments Incorporated
LP8580 Evaluation Board
3
Hardware Setup
shows how to set up LP8580EVM. An external 2.9-V to 5-V power source must be connected to
VDD input connector, and boost input voltage between 2.7 V to 27 V must be connected to the VIN
connector. If an onboard microcontroller is used, the LP8580EVM must be connected to a Windows
®
PC
with a USB cable.
Figure 2. LP8580EVM Hardware Setup
3.1
LED Connectors
An external LED load board must be connected to LED connectors. Use of six strings of white LEDs with
3 to 13 LEDs in each string is recommended. The sum of LED forward voltages of the LED strings must
be between 10 V to 40 V. Either connector (J121 or J111) can be used to connect the LEDs. Connector
J111 has series resistors on the LED outputs and boost output, while the connector J121 connects
straight to LED output pins (see
for connection details). LED anodes must be connected to
BOOST pin and the cathodes to LEDx pins. The GND pin is provided for measurement purposes only and
does not need to be connected to the LEDs.
If LEDs are connected to connector J111, connector J122 can be used to measure the individual LED
currents and boost converter output current. LEDx– and LEDx OUT pins connect to the different sides of
the current sense resistors and LED current can be measured by connecting a voltage meter on these
pins. BOOST and BOOST OUT pins connect to the different sides of the boost output current sense
resistor. Boost output has a 1-
Ω
current sense resistor while LED outputs have 10-
Ω
current sense
resistors.
3.2
VCC and VDD Jumpers
The VDD jumper selects the VDD input voltage source for the LP8580 IC. If the VDD jumper is set to the
EXT side the LP8580 is powered from a external voltage source that is connected to the external VDD
supply connector (J101). If the VDD jumper is set to the VUSB side, the LP8580 IC is powered from a
USB ports 5-V input voltage. Note that boost converter input voltage always comes from the VIN input
connectors.
