Vicor Micro Family of DC-DC Converter - Manual (Page 59)

Design Guide & Applications Manual
For Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies
Maxi, Mini, Micro Design Guide Rev 4.9 vicorpower.com
Page 58 of 88
Apps. Eng. 800 927.9474 800 735.6200
12. Output Ripple Attenuator Module (MicroRAM)
Frequency
10 Hz 100 Hz 1.0 KHz 10 KHz 100 KHz 1.0 MHz
... DB(V(VOUT))
-75
-50
-25
-0 Rhr = 260 k (Vheadroom = 90 mV)
250 k (100 mV)
240 k (110 mV)
230 k (122 mV)
220 k (135 mV)
210 k (150 mV)
200 k (160 mV)
190 k (180 mV)
180 k (197 mV)
170 k (217 mV)
160 k (240 mV)
150 k (260 mV)
Vout = 28 V load = 20 A
100 degrees baseplate temperature
Figure 12–4b — Graph of simulated results demonstrating the tradeoff of attenuation vs. headroom setting at 20 A and a equivalent 100°C
baseplate temperature at 28 V.
17 k
18 k
19 k
20 k
21 k
22 k
23 k
24 k
25 k
26 k
27 k
Rhr=28 k
-70
-60
-50
-40
-30
-20
-10
3.0 3.5 4.0 4.5 5.0 5.5 6.0
Watts
500 khz 3 V
1 Mhz 3 V
100 khz 3 V
dB
Figure 12–4c — MicroRAM attenuation vs. power dissipation at 3 V, 20 A
Rhr = 260 k
250 k
240 k
230 k
220 k
210 k
200 k
190 k
180 k
170 k
160 k
150 k
-70
-60
-50
-40
-30
-20
-10
3.0 3.5 4.0 4.5 5.0 5.5 6.0
Watts
dB
100 khz 28 V
500 khz 28 V
1 Mhz 28 V
Figure 12–4d — MicroRAM attenuation vs. power dissipation at 28 V, 20 A
Frequency
10 Hz 100 Hz 1.0 KHz 10 KHz 100 KHz 1.0 MHz
... DB(V(VOUT))
-75
-50
-25
-0
Vout = 3 V load = 20 A
100 degrees baseplate temperature Rhr = 28 k (Vheadroom = 90 mV)
27 k (100 mV)
22 k (160 mV)
23 k (150 mV)
24 k (135 mV)
25 k (122 mV)
26 k (110 mV)
17 k (260 mV)
18 k (240 mV)
19 k (217 mV)
20 k (197 mV)
21 k (180 mV)
Figure 12–4a — Graph of simulated results demonstrating the tradeoff of attenuation vs. headroom setting at 20 A and a equivalent 100°C
baseplate temperature at 3 V.