Datasheet

Power Up/Down Procedure www.ti.com
6 Power Up/Down Procedure
1. Working at an ESD workstation, make sure that any wrist straps, bootstraps or mats are connected
referencing the user to earth ground before power is applied to the unit. electrostatic smock and safety
glasses should also be worn.
2. Prior to connecting the DC input source, V
IN
, it is advisable to limit the source current from V
IN
to 3.5 A
maximum. Make sure V
IN
is initially set to 0 V and connected to J1 as shown in Figure 2.
3. Connect the ammeter A1 (0 A to 10 A range) between V
IN
and J1 as shown in Figure 2.
4. Connect voltmeter (can optionally use voltmeter from V
IN
source if available), V1 across V
IN
as shown
in Figure 2.
5. Connect LOAD1 to J8 as shown in Figure 2. Set LOAD1 to constant current mode to sink 0 A
DC
before
V
IN
is applied.
6. Connect voltmeter, V2 across J9 and J10 as shown in Figure 2.
7. Increase V
IN
from 0 V to 36 V
DC
.
8. Observe that V
OUT
is regulating when V
IN
is at 36 V.
9. Increase V
IN
to 48 V.
10. Increase LOAD1 from 0 A to 15 A
DC
.
11. Turn on fan making sure to blow air directly on the unit.
12. Increase LOAD1 from 15 A
DC
to 30 A
DC
.
13. Decrease LOAD1 to 0 A.
14. Decrease V
IN
from 48 V
DC
to 0 V.
15. Shut down V
IN
8
48-V to 3.3-V Forward Converter with Active Clamp Reset —Using the SLUU357–November 2009
UCC2897A Active Clamp Current Mode —PWM Controller
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