HIP6004EVAL3 Intersil, HIP6004EVAL3 Datasheet - Page 4

• Manufacturer Part Number: HIP6004EVAL3
• Description: EVALUATION BOARD EMBED HIP6004
• Manufacturer: Intersil

Specifications of HIP6004EVAL3

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 1.3 ~ 3.5V
• Current - Output: 14A
• Voltage - Input: 5 ~ 12V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: HIP6004
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -
• Frequency - Switching: -

The average voltage drop equals the DC output current times
the DC winding resistance of the output inductor. Instead of
straight voltage feedback, an averaging filter (R9 and C14 in
the schematics) is added around the output inductor. This filter
communicates both the output voltage and droop information
back to the PWM controller. A resistor (R3) increases the
light-load voltage above the DAC program level.
OC Protection
Both the HIP6004EVAL3 and HIP6005EVAL3 have lossless
overcurrent (OC) protection. This is accomplished via the
current-sense function of the HIP600x family. The HIP6004
and HIP6005 sense converter load current by monitoring the
drop across the upper MOSFET (Q1 in the schematics). By
selecting the appropriate value of the OCSET resistor (R6),
an overcurrent protection scheme is employed without the
cost and power loss associated with an external current-
sense resistor. See the Over-Current Protection section of
either the HIP6004 and HIP6005 data sheet for details on
the design procedure for the OCSET resistor.
Enable Function
The HIP6004EVAL3 and HIP6005EVAL3 can be disabled by
pulling the SS pin below 1.2V. A simple way to incorporate
an open collector ENABLE function is shown in Figure 9.
Modifications for Lower Cost Solutions
The HIP6004EVAL3 and HIP6005EVAL3 reference designs
are designed with adequate margins for reliable operation
when powering Pentium Pro and future Intel processors.
Some system designers may wish to be more aggressive
with the design of the DC-DC converter to have a lower cost
solution. This section describes how the evaluation boards
can be tailored for lower-cost systems.
FIGURE 8. STATIC REGULATION OF THE HIP6004/5EVAL3
ENABLE
FIGURE 9. DIODE PROVIDES ENABLE FUNCTION
2.85
2.80
2.75
0
OUTPUT CURRENT (A)
5
SS
4
HIP6004
HIP6005
NORMAL: ENABLE = OPEN
OR
INHIBIT: ENABLE = GND
10
WITHOUT DROOP
WITH DROOP
Application Note 9706
15
OV Protection
The HIP6004/5EVAL3 contains circuitry to protect against
output overvoltage (OV) conditions. When an overvoltage
(greater than 15% over the nominal Vout) occurs, the
HIP6004 (or HIP6005) fires an SCR (Q3) and the input fuse
will open.
For applications where this feature is not necessary, the
following components may be eliminated: F1, Q3, and R4.
Bulk Input Capacitors
The HIP6004/5EVAL3 boards use five 330 F aluminum
electrolytic capacitors to handle the high RMS current
ratings of a buck converter in a high-performance
microprocessor application. Each of these capacitors is
rated for about 1A of RMS current by the manufacturer. The
RMS current requirement of the total bulk input capacitor is
roughly equal to 1/2 of the converter load. If the average
processor current draw is 10A, than five input capacitors
meet this rating.
However, the capacitor manufacturer RMS current ratings
are based on worst-case ESR of the capacitors and are
conservative. Exceeding the current ratings may shorten the
life of the capacitors, but an expected life reduction from 8
years to say 5 years, for example, may be acceptable for
many applications.
With caution and working with the capacitor supplier, it may
be possible to safely remove 1-2 of the bulk input capacitors.
This action should be balanced by the relatively small cost
savings associated with the removal of the capacitors.
Output Capacitors
Low-ESR aluminum electrolytic capacitors are also used on
the output of the converter in the HIP6004/5EVAL3. This is
not the only choice for this type of application, but it is the
lowest cost. Refer to the Component Selection Guidelines in
the data sheets for additional information. Nine parallel
capacitors are used to meet Intel-specified regulation of 5%
over all variations including temperature, load transients,
and component life. It is the load transient requirements
which pose the largest challenge, as discussed earlier in this
application note.
Figures 3-4 and 6-7 show that the reference designs meet
margin. This margin is by design to allow for manufacturing
variations in the reference voltage and the capacitors
parasitics and temperature effects. The HIP6004 and
HIP6005 voltage reference and DAC have an outstanding
accuracy of 1% over temperature.
For applications where cost or volume is especially
sensitive, and the 5% regulation number is not critical
over all worst-case situations, the number of output
capacitors may be reduced. Figures 10 and 11 show the
HIP6004EVAL3 0A-14A transient response with only five
output capacitors. These oscillograms show that the
5% regulation in response to a 0A-14A load transient with