HCPL-7710-000E Datasheet, PDF (15/18 Pages) AVAGO TECHNOLOGIES LIMITED – 40 ns Propagation Delay, CMOS Optocoupler

Isolated Node Providing Power to the Network
Figure 21 shows a node providing power to the
network. The AC line powers a regulator which provides
five (5) volts locally. The AC line also powers a 24 volt
isolated supply, which powers the network, and another
five-volt regulator, which, in turn, powers the transceiv-
er and isolated (network) side of the two optocouplers.
This method is recommended when there are a limited
number of devices on the network that don’t require
much power, thus eliminating the need for separate
power supplies.
More importantly, the unique “dual-inverting” design
of the HCPL-x710 ensure the network will not “lock-up”
if either AC line power to the node is lost or the node
powered-off. Specifically, when input power (V_DD1) to
the HCPL-x710 located in the transmit path is eliminat-
ed, a RECESSIVE bus state is ensured as the HCPL‑x710
output voltage (V_O) go HIGH.
DEVICENET NODE
NODE/APP SPECIFIC
uP/CAN
HCPL
0710
HCPL
0710
TRANSCEIVER
DRAIN/SHIELD
SIGNAL
POWER
Figure 21. Isolated node providing power to the network.
AC LINE
5 V REG.
5 V REG.
ISOLATED
SWITCHING
POWER
SUPPLY
GALVANIC
ISOLATION
BOUNDARY
V+ (SIGNAL)
V– (SIGNAL)
V+ (POWER)
V– (POWER)
HCPL-0710 fig 20
15