UM0581

Design details

Doc ID 14961 Rev 1

11/26

Table 1.

Setting up of power supply

Power supply

Description

ATX-SMPS

The board has the option to power from ATX-SMPS. Connect the ATX-PW-ON connector to

SMPS_PW_CONN (J5) indicated on the board. Since ATX-SMPS provides 12 V and 5 V

needed for the external HDD, there is no need for L4960 and L4978 switching regulators. So,

setting the below jumpers isolates the onboard power supply circuit (L4960, L4978) from the

HDD.

Jumper settings are as follows:

– J4: open

– J6: open (not used)

– J8: open

– J9: connect the jumper between pin 1 and 2

12 V DC power (this

should meet the

hard disk current

requirements)

The board has a power-on provision using a 12 V DC adapter. Connect the 12 V DC adapter

to J3 or J7. Since we are using 12 V directly, there is no need for an L4960 switching

regulator.

Jumper settings are as follows:

– J7 or J3: 12 V DC adapter is inserted

– J5: open (not used)

– J4: connect the jumper between pin 2 and 3

– J8: connect the jumper between pin 2 and 3

– J9: connect the jumper between pin 2 and 3

– J6: power on the external hard disk by connecting the hard disk power-on connector

between J6 and the hard disk