USB-231-OEM User's Guide
Functional Details
17
To use the LED signal to monitor the device state, refer to the circuit in Figure 9.
Figure 9. Circuit to monitor device state with LED signal
+VO power source
Figure 10 shows the
+VO
power source circuitry of the USB-231-OEM.
Figure 10. +VO power source circuitry
The main blocks featured in the
+VO
power source circuitry are as follows:
+5 V Source
—Regulated 5 V supply.
+5 V Protection
—Circuit for overvoltage, over current, and short circuit protection.
The +5 V source is limited at 200 mA typically. In case of hard short circuit to ground, this limit is further
reduced to avoid excessive power dissipation.
Connecting the load
The return connector for the +5 V source is the
GND
connector. The +5 V load should be connected between
the
+VO
connector and
GND
. The current delivered by the USB-231-OEM at the
+VO
connector is sourced
from the USB connector. To meet the USB specifications, a maximum of 150 mA can be used from the
+VO
connector.