Datasheet

Channel B
20 LOG
Channel A
æ ö
´
ç ÷
è ø
0 2 4 6 8 10
I -LoadCurrent- A
L
50
55
60
65
70
75
80
85
90
95
h -Efficiency-%
8V
12V
14V
V =8V-14V,
V =1.8V,
I =0-10 A
IN
OUT
OUT
TPS40305EVM-488 Test Data www.ti.com
2. Connect a 1-kHz – 1-MHz isolation transformer to TP5 and TP7 as shown in Figure 4
3. Connect input signal amplitude measurement probe (channel A) to TP7 as shown in Figure 4
4. Connect output signal amplitude measurement probe (channel B) to TP5 as shown in Figure 4
5. Connect ground lead of channel A and channel B to TP6 and TP8 as shown in Figure 4
6. Inject 30mV or less signal across R3 through isolation transformer
7. Sweep frequency from 1kHz to 1MHz with 10-Hz or lower post filter
8. Control loop gain can be measured by
9. Control loop phase can be measured by the phase difference between channel A and channel B
10. Control to output response (power stage transfer function) can be measured by connecting channel A
probe to TP10 (COMP) and channel B probe to TP5 (CHB)
11. Output to control response (compensated error amplifier transfer function) can be measured by
connecting channel A probe to TP7 (CHA) and channel B probe to TP10 (COMP)
12. Follow section 5.3 Start-Up / Shut-Down Procedure steps 6 and 7 to power down
5.6 Equipment Shutdown
1. Shut down oscilloscope
2. Shut down LOAD1
3. Shut down VIN
4. Shut down fan
6 TPS40305EVM-488 Test Data
Figure 5 through Figure 11 present typical performance curves for the TPS40305EVM-488. Since actual
performance data can be affected by measurement techniques and environmental variables, these curves
are presented for reference and may differ from actual field measurements.
6.1 Efficiency
V
IN
= 8.0V – 14V, V
OUT
= 1.8V, I
OUT
= 0A – 10A
Figure 5. TPS40305EVM-488 Efficiency vs Load Current
10
TPS40305EVM-488 SLUU406–February 2010
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