ISL6558EVAL1 Intersil, ISL6558EVAL1 Datasheet - Page 15

• Manufacturer Part Number: ISL6558EVAL1
• Description: EVAL BOARD W/LOAD TESTER ISL6
• Manufacturer: Intersil
• Series: Endura™r

Specifications of ISL6558EVAL1

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Power - Output: 150W
• Voltage - Output: 1.5V
• Current - Output: 100A
• Voltage - Input: 5V, 12V
• Regulator Topology: Buck
• Frequency - Switching: 500kHz
• Board Type: Fully Populated
• Utilized Ic / Part: HIP6601, ISL6558
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

OVERVOLTAGE SHUTDOWN
With the COMP pin momentarily tied to a 4V voltage
source with respect to the ground, the error voltage
jumps high and the duty cycle increases. Thus, the
output voltage rises up immediately until it reaches the
overvoltage threshold setting the OV latch and triggers
the PWM outputs low. PGOOD is pulled low indicating
output out of regulation, as shown in Figure 27.
Conclusion
The superior performance of Intersil’s ISL6558 4-phase
controller, coupled with Intersil’s ISL6612A driver, has
been demonstrated in the reference design of a 150W
interleaved DC-DC buck converter. An efficiency of 83%
at 1.527V output and 100A full load has been achieved.
The reference design provides an option to implement
droop or no droop and allows users to evaluate the
transient performance with the on-board load transient
generator.
This application note provides a step-by-step design
procedure for the multi-phase converter, which allows
for easier component selection and customization of this
reference design for a broader base of applications.
Users can use equations, presented in the section
entitled “Converter Design” on page 3, to fully
characterize power-train components such as the I/O
filters and synchronous rectifiers. By entering these
calculations in a worksheet, users can do numerical
iterations and choose appropriate components and
switching frequency for their applications in an
user-friendly manner. Furthermore, the loop response
of the system can be roughly approximated using the
simplified model.
In addition, extensive experimental results give users a
better understanding of the operation of the converter,
the ISL6558 four-phase PWM controller, and the
ISL6612A synchronous-rectified driver.
FIGURE 27. OVERVOLTAGE WAVEFORMS
V
O
15
PGOOD
Application Note 1029
ΔV
I
I
ΔV
IN,RIPPLE
I
I
I
I
I
INCAP,PP
Lo,PEAK
Q1,RMS
Q2,RMS
TERM
dV
ESR
Dmax
dV
ΔV
IN,RMS
I
Lo,RMS
IN,TRAN
Istep
dV
Lcr1
Lcr2
ESR
Lo,PP
IN,CAP
ESL
Fsw
IQ1
IQ2
I
Cin
I
I
I
Lin
Co
He
Ho
Lo
Io
f
DR
LO
D
IN
PP
ESR
ESL
ESL
c
Co
IN
Input Capacitance
Output Capacitance
Ratio of ON Interval of Upper FET to Single
Channel Switching Period, Duty Cycle
Maximum Duty Cycle of the Controller
Output Voltage Ripple due to Output Capacitance
Ripple Voltage Contributed by ESL of Output
Capacitors
Ripple Voltage Contributed by ESR of Output
Capacitors
Initial Transient Spike due to ESL
Allowable Input Voltage Ripple Contributed by
the Input Capacitors
Voltage dip at Input Capacitors due to Load
Transient
Overall ESL of Output Capacitors
Overall ESR of Output Capacitors
Overall ESR of Input Capacitors
System Closed-Loop Bandwidth
Per-Channel Switching Frequency
Transfer Function of Error Amplifier
Open Loop Transfer Function for Simplified Model
Driver Current
Input Current
RMS Current thru Input Capacitors
Ripple Current thru Input Inductor
Peak-to-Peak Current thru Input Capacitors
Current thru Each-Channel Inductor
Peak Current thru Each-Channel Inductor
Ripple Current thru Each-Channel Inductor
RMS Current thru Each-Channel Inductor
Overall Ripple Current thru Output Capacitors
Output Load Current
Current thru Upper FET, Q1
RMS Current thru Upper FET, Q1
Current thru Lower FET, Q2
RMS Current thru Upper FET, Q2
Load Transient Step
Critical Inductance for Step-up Load Transient
Critical Inductance for Step-down Load Transient
Inductance of Each-Channel Inductor
Input Inductor
TABLE 6. TERM DEFINITIONS
DEFINITIONS
July 31, 2009
AN1029.3