ISL6551EVAL1 Intersil, ISL6551EVAL1 Datasheet - Page 42

• Manufacturer Part Number: ISL6551EVAL1
• Description: EVALUATION BOARD ISL6551
• Manufacturer: Intersil

Specifications of ISL6551EVAL1

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Isolated
• Voltage - Output: 3.3V
• Current - Output: 60A
• Voltage - Input: 36 ~ 75V
• Regulator Topology: Buck
• Frequency - Switching: 470kHz
• Board Type: Fully Populated
• Utilized Ic / Part: ISL6551
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -

FIGURE 106. V
FIGURE 104. V
FIGURE 105. V
WITH 1000UF ALUMINUM CAPACITOR. CHANNEL 1:
OUTPUT VOLTAGE; CHANNEL 2: SYNCHRONOUS
FET GATE SIGNAL; CHANNEL 4: OUTPUT CURRENT
LOAD WITH NO ADDITIONAL CAP. CHANNEL 1:
OUTPUT VOLTAGE; CHANNEL 2: SYNCHRONOUS
FET GATE SIGNAL; CHANNEL 4: OUTPUT
CURRENT
LOAD WITH NO ADDITIONAL CAP. CHANNEL 1:
OUTPUT VOLTAGE; CHANNEL 2: SYNCHRONOUS
FET GATE SIGNAL; CHANNEL 4: OUTPUT
CURRENT
IN
IN
IN
=48V, V
=48V, V
=48V, V
OUT
OUT
OUT
=3.3V, I
=3.3V, I
=3.3V, I
42
OUT
OUT
OUT
=60A ELECTRONIC LOAD
=60A PURE RESISTIVE
=60A PURE RESISTIVE
Application Note 1002
As shown in Figure 105, the output voltage and the output
current are in phase since the load is resistive (two DALE
NH-25 25W 0.1W in parallel, they operate for only a short
period due to their power ratings). The negative spike is
much smaller than that of the previous case because the
load helps dissipate some of the residual energy. When the
synchronous FETs are turned off at the shutdown of the
converter, the body diodes of the synchronous FETs help
dissipate a large portion of the energy and block any
negative current through the output inductors resulting in
zero negative spike, as shown in
Figure 106. In this case, no extra capacitor is required.
Equipment List
Schematics Description
There are six pages of schematics. On the first page is the
secondary side power train including the output filter and the
synchronous rectifiers with their drivers. Additional circuits
are used to turn off the synchronous FETs during the start
up and to clamp the ringings across the FETs on the leading
edge. On page 2 is the primary power train. It consists of an
input filter, current transformer, main transformer, pulse
transformer, and full-bridge power switches with their drivers.
On page 3 are the main supervisor circuits ISL6550 with
some external resistor components, which can differentially
sense the output voltage, set the output under-voltage and
over-voltage protection, program the output reference with
four VID inputs, and set an appropriate output under-voltage
lockout delay. On page 4 are the full-bridge controller and the
master over-voltage circuit. On page 5 are the input under-
voltage and thermal condition detecting circuits. The circuits
on the last page are used to monitor the output load level
during the start up. It turns off the synchronous FETs during
the start up at low load conditions. Once the FETs are turned
Boards Used
Power Supplies
Oscilloscope
Differential Probe
Multimeters
Load
Current Probe Amplifier
Temperature Probe
Fan
EQUIPMENT
TABLE 8. EQUIPMENT LIST
ISl6551EVAL1 Rev. B, #1, #2, #3, & #4
1. HP 6653A S/N: 3621A-03425
2. Lamda LQ521 S/N: J 3570
3. XANTREX 100-10 S/N: 72963
4. XANTREX 100-6 S/N: 66287
5. HP6205C S/N: 2411A-06136
LeCroy LT364L S/N: 01106
Hewlett Packard HP1141A
Fluke 8050A S/N: 2466115 & 3200834
1. Chroma 63103 S/N: 631030002967
2. Chroma 63103 S/N: 631030003051
3. Four DALE NH-25 25W 0.1Ω 1%
LeCroy AP015 SN: 970139
Fluke 80T-IR Infrared Temperature
Probe (93/09)
POPST-MOOREN TYP 4600X (4098547)
EQUIPMENT DESCRIPTIONS