Evaluating The Adp1071-1Evalz Board; Startup; Cross Regulation - Analog Devices ADP1071-1EVALZ User Manual

ADP1071-1EVALZ

EVALUATING THE ADP1071-1EVALZ BOARD

Test points on the evaluation board allow the user to monitor
output signals. The following sections provide descriptions of
the typical results when evaluating the device in a multiflyback
topology. The user can modify the operation of the device
according to the ADP1071-1/ADP1071-2

STARTUP

When the supply voltage is on, the output voltages ramp up
smoothly. For details about two-stage soft start, refer to the
ADP1071-1/ADP1071-2 data sheet. Figure 4 shows the startup
under a no load condition, and Figure 5 shows the startup of a
full load condition.
1
CH1 10.0V B CH2 10.0V
W
B
CH3 10.0V
W
Figure 4. Startup at No Load
1
B
CH1 10.0V CH2 10.0V
W
B
CH3 10.0V
W
Figure 5. Startup at Full Load
To experiment with different soft start timings, see more details
in the soft start section in the
sheet.

CROSS REGULATION

On the secondary side, the output voltage information of the
5.5 V rail and the 24 V rail are sensed by a voltage divider
network and sent to the FB pin. These two voltages (5.5 V and
24 V) are partially regulated by a weightage ratio of 6:4. The
−15 V rail is left quasi regulated due to its relatively low load
current rating. The user can adjust the feedback weightage ratio
User Guide
data sheet as needed.
+24V
+5.5V
–15V
B M40.0ms A CH1 9.60V
W
T 9.0000ms
+24V
+5.5V
–15V
B
M40.0ms A CH1 9.60V
W
T 9.0000ms
ADP1071-1/ADP1071-2 data
according to the regulation requirement and load rating to
achieve the most optimal cross regulation among the three
outputs. Figure 6 through Figure 9 show the cross regulation
performance under different load conditions.
1
4
+24V
AT FULL
LOAD
3
CH1 500mA
CH3 5.00V
Figure 6. Cross Regulation with Load Step at a +5.5 V Rail When +24 V and
1
4
+24V
3
CH1 500mA CH2 1.00V
CH3 5.00V
Figure 7. Cross Regulation with Load Step at a +24 V Rail When +5.5 V and
1
4
+24V
AT NO
LOAD
3
CH1 500mA
CH3 5.00V
Figure 8. Cross Regulation with Load Step at a +5.5 V Rail When +24 V and
Rev. 0 | Page 5 of 13
5.5V LOAD STEP
0mA TO 500mA
AT FULL
+5.5V
CH2 1.00V A CH1
CH4 5.00V
−15 V Rails at Full Load
5.5V LOAD STEP
0mA TO 500mA
AT FULL
+5.5V
AT FULL
LOAD
A CH1
CH4 5.00V
−15 V Rails at Full Load
5.5V LOAD STEP
0mA TO 500mA
AT NO
+5.5V
LOAD
CH2 1.00V A CH1
CH4 5.00V
−15 V Rails at No Load
UG-1384
–15V
LOAD
270mA
–15V
LOAD
135mA
–15V
270mA