ISL6558EVAL2 Intersil, ISL6558EVAL2 Datasheet - Page 4

• Manufacturer Part Number: ISL6558EVAL2
• Description: EVAL BOARD W/6605 DRVRS ISL6558
• Manufacturer: Intersil
• Series: Endura™r

Specifications of ISL6558EVAL2

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 1.35V
• Current - Output: 30A
• Voltage - Input: 4.5 ~ 5.5V
• Regulator Topology: Buck
• Frequency - Switching: 500kHz
• Board Type: Fully Populated
• Utilized Ic / Part: HIP6609, ISL6558
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -

Experimental Results
The ISL6558EVAL2 evaluation board as configured is
capable of 30A continuous load current and handling
200A/µs or higher speed load transients. The evaluation
board meets the design specifications indicated in Table 1.
Table 4 summarizes the equipment that was used for the
performance evaluation.
ISL6558EVAL2 OPERATION AND MODIFICATION TIPS
• Apply the input voltage (VIN) prior to the control voltage
• SW1 is used to engage or remove the load transient
• Droop option is not selected in the reference design since
• For 3-phase operation, add the current sense resistor R17
• For 4-phase operation, add the current sense resistors R2
• Use R25, R26, R28, and R29 to program the load
VCC5 (5V). This sequencing results in initializing the
ISL6609 driver before the ISL6558 starts, and retains the
soft-start interval. Vice versa, the ISL6558 could produce
maximum duty cycle PWM drive signal, which results in an
overcurrent or overvoltage trip due to lack of soft-start.
The evaluation board is configured to power up from a
single 5V supply, and it eliminates the problem discussed
above.
generator.
the required load transient step is not greater than 50% of
the full load. In another word, the droop only helps reduce
the number of output capacitors and still retains the same
transient performance when the load transient step is
greater than 50% of full load.
and place JP4 to ON position (away from TP8). The
compensation gain (R11) should be scaled by 2/3 for
system stability with a reasonable phase margin.
& R17 and place JP4 &JP2 to ON position (away from
TP8 and TP5). The compensation gain (R11) should be
scaled by 1/2 for system stability with a reasonable phase
margin.
transient speed. The higher values these resistors, the
slower the transient.
Power Supplies
Current Probe
Boards Used
Oscilloscope
Equipment
Multimeters
Amplifier
Load
Fan
TABLE 4. EQUIPMENT LIST
ISL6558EVAL2 Rev. A, #1 and #2
1. Hewlett Packard 6653A, 35V, 15A. S/N:
3621A-03425
LeCroy LT364L. S/N: 01106
Fluke 8050A. S/N: 2466115 & 3200834
1. Chroma 63103. S/N: 631030002967
2. Chroma 63103. S/N: 631030003051
LeCroy AP015. SN: 3293
POPST-MOOREN TYP 4600X (4098547)
EQUIPMENT DESCRIPTIONS
4
Application Note 1044
• If there is sufficient airflow, use a single LPAK Hitachi
• For 12V input operation, the jumper JP1 should be
• Any change of the output filter will require the
• The feedback resistor (R19) can cause some delay in the
EFFICIENCY
The efficiency data, as plotted in Figure 3, are taken with a
PAPST-MOTOREN TYP 4600X fan turned on 8” away from
the input end of the evaluation board at room temperature
(approximate 200LFM). This figure shows that the converter
operates less efficiently at high line and low-to-medium load
since the switching loss is the dominant portion of the total
losses in that operating condition. As the load increases, the
dominant conduction losses help cut down the difference.
HAT1264 for the upper FET and two SO-8 Siliconix
Si4842DYs for the lower FETs in each channel; but it
comes with the penalty of 1% lower efficiency, as shown in
Table 5. Note that the current sense resistors (R2 and
R17) need to be adjusted to get a proper over current
setpoint.
removed to prevent the controller and drivers from
overvoltage damage. A 5V supply is required to power up
the controller and the drivers; the diode D1 is to protect
both the drivers and controller from reversed-bias
damage. The 12V supply should be applied prior to the
5V; otherwise, the output voltage will lack soft-start and
cause an over overcurrent or overvoltage at the output.
Furthermore, the input capacitors should be replaced with
higher voltage rating (16V or above) capacitors. In
addition, the compensation gain (R11) should be scaled
by 5/12 for system stability with a reasonable phase
margin.
compensation network to change for an optimum transient
response. If very lower ESR capacitors are used at the
output, a type III compensation network is required to
boost up the phase for a better transient performance.
soft-start interval, as discussed in the ISL6557A data
sheet section SOFT-START [3]. It should not be a very
high impedance resistor.
FIGURE 3. EFFICIENCY AT 500kHz AND 200LFM
92
91
90
89
88
87
86
85
84
83
5
4.5V
10
V
IN
= 5.5V
15
Iout (A)
20
25
5.0V
April 4, 2006
30
AN1044.2