an9888

HIP6302EVAL1 - Multiphase Power Conversion
for AMD Athlon Processors up to 35A
TM
Application Note
February 2002
AN9888.1
Author: Matt Harris
Introduction
Each generation of computer microprocessor brings
performance advances in computing power. Performance
improvements are made possible by advances in fabrication
technology that enable greater device density. Newer
processors are operating at lower voltages and higher clock
speeds both of which contribute to greater demands on the
microprocessor core voltage supply in terms of higher peak
currents and higher current-slew rates.
Intersil’s family of multi-phase DC-DC converter solutions
provide the ideal solution to supply the core-voltage needs of
present and future high-performance microprocessors.
Intersil HIP6302 and HIP6601
The HIP6302 controller IC works with two HIP6601A or
HIP6603A single-channel driver ICs or a single HIP6602A
dual-channel driver IC [3] to form a highly integrated solution
for high-current, high slew-rate applications. The HIP6302
regulates output voltage, balances load currents and
provides protective functions for two synchronous-rectified
buck-converter channels.
VSEN
10
x 0.9
PGOOD
VCC
15
16
POWER-ON
RESET (POR)
UV
+
-
x 1.15
PVCC
7
VCC
6
2 BOOT
1 UGATE
+5V
10k
8
3
SHOOT
THROUGH
PROTECTION
CONTROL
LOGIC
FS/DIS
10k
CLOCK AND
SAWTOOTH
GENERATOR
S
OVP
+
-
The HIP6601A is a driver IC capable of delivering up to 2A of
gate-charging current for rapidly switching both MOSFETs in
a synchronous-rectified bridge. The HIP6601A accepts a
single logic input to control both upper and lower MOSFETs.
Adaptive shoot-through protection is provided on both
switching edges to provide optimal dead time, and bootstrap
circuitry permits greater enhancement of the upper
MOSFET. For a more detailed description of the HIP6601A,
refer to the HIP6601A Data Sheet [2].
PWM
THREE STATE
OV
LATCH
provides feedback for droop compensation and over-current
protection. A five-bit DAC provides a digital interface to
program the 1% accurate reference and a window
comparator toggles PGOOD if the output voltage is out of
range and acts to protect the load in case of over voltage.
For more detailed descriptions of the HIP6302 functionality,
refer to the HIP6302 Data Sheet [1].
8 PHASE
5 LGATE
4
GND
FIGURE 2. HIP6601A BLOCK DIAGRAM
SOFT START
AND FAULT
LOGIC
COMP
6
VID4
VID3
VID2
VID1
VID0
1
2
3
4
5
PWM
+
∑
-
PWM
+
DAC
+
-
E/A
13 PWM1
+
-
∑
-
12 PWM2
+
-
The HIP6302EVAL1 Board and Reference
Design
With the VID jumpers set to 1.7V (00110), the evaluation
board meets the output voltage and current specifications
indicated in Table 1.
TABLE 1. HIP6302EVAL1 OUTPUT PARAMETERS
CURRENT
DETECTION
MIN
MAX
Static Regulation
1.65V
1.75V
Transient Regulation
1.60V
1.85V
Over-Voltage Protection
1.90V
2.00V
Continuous Load Current
-
35A
Over-Current Trip Level
41A
57A
Load-Current Transient
-
35A/µs
FB 7
∑
14 ISEN1
+
11 ISEN2
+
9
GND
FIGURE 1. HIP6302 BLOCK DIAGRAM
The integrated high-bandwidth error amplifier provides
voltage regulation, while current-sense circuitry maintains
phase-current balance between the two power channels and
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2002. All Rights Reserved
Application Note AN9888
The HIP6302EVAL1 evaluation board incorporates a
reference design intended to meet the core-voltage
requirements for AMD Athlon microprocessors up to 35A.
Additional circuitry is provided to facilitate circuit evaluation
including input and output power connectors, VID jumpers,
numerous probe points, an LED power-good indicator, and a
load-transient generator.
Powering the HIP6302EVAL1
Start Up
The waveforms in Figure 3 demonstrate the normal start-up
sequence with the HIP6302EVAL1 connected to a 55mΩ
load. After FS/EN is released, VCORE exhibits a linear ramp
until reaching its 1.7V set point. The gradual increase of
VCORE over approximately 5ms limits the current required
from the input supply, ICC5, to a level that does not strain the
supply. The HIP6302 asserts PGOOD once VCORE is within
regulation limits.
For convenience, the HIP6302EVAL1 provides two methods
of making input power connections. The 20-pin header, J1,
interfaces with a standard ATX power supply and may be the
most convenient method of powering the board.
FS/EN, 5V/DIV
J2, J3, and J4 are standard banana-jack connectors that can
be used to supply power using bench-top power supplies.
These inputs provide greater versatility in testing and design
validation by allowing the 12V and 5V power-input voltage
levels to be varied independently. In this way power-on level
and power-sequencing issues can be easily examined.
0V
To start the evaluation board, insert the 20-pin connector
from an ATX supply into J1. If using bench-top supplies,
connect a 12V supply to J2 and a 5V supply to J3. Connect
the grounds from both supplies to J4.
0A
VCORE, 1V/DIV
0V
ICC5, 10A/DIV
PGOOD, 5V/DIV
0V
1ms/DIV
Important
FIGURE 3. HIP6302EVAL1 START-UP WAVEFORMS
There are two things to consider when using bench-top
supplies. If the 5V supply is applied prior to the 12V supply,
the HIP6302 will begin operating before the HIP6601As. This
allows the HIP6302 to complete its soft-start cycle before the
drivers are capable of switching power to the output. When
the 12V power input is then applied, there is a large transient
as the controller tries to instantly bring the output to its fullvoltage level. This can result in an overcurrent protection
cycle and an abnormal start-up waveform. It can be avoided
by applying 5V supply after or at the same time as the 12V
supply or by using an ATX power supply.
The second problem can occur when operating the transient
load generator. Not all bench-top and ATX power supplies
are capable of responding to load transients, and they may
allow a momentary voltage dip on VCC5. This can activate
the power-on-reset function in the HIP6302 and cause the
output power to cycle. It can be remedied by connecting a
5600µF or larger capacitor between VCC5 and ground. The
capacitor, if necessary, simulates the distributed capacitance
that exists on the computer motherboard.
2
Transient Response
The HIP6302EVAL1 is equipped with a load-transient
generator that applies a 0–36A transient load current with
rise and fall rates of approximately 35A/µs. The duration of
the transient is between 100µs and 200µs, and the repetition
rate is kept low in order to limit power dissipation in the load
MOSFETs and resistors. Removal of the HI/LO jumper (JP2)
causes the current to decrease from about 36A to about
31A. The load-transient generator operates when the
HIP6302EVAL1 is properly connected to a 12V power
source and SW1 is in the ON position. Operation ceases
when SW1 is moved into the OFF position or 12V is
removed from the board.
The HIP6302EVAL1 achieves the specified transient
performance while maintaining a favorable balance between
low cost, high efficiency and small profile. When the duty
cycle changes rapidly in response to a transient load current,
the inductor current immediately begins to change in order to
meet the demand. During the time the inductor current is
increasing, the output-filter capacitors are supplying the
load. It follows that the amount of required capacitance
decreases as the capability of the inductors to rapidly
assume the load current increases.
Athlon™ is a trademark of Advanced Micro Devices, Inc.
Application Note AN9888
Figure 4 shows the core voltage, inductor current, and PWM
signals changing in response to the transient load current.
The upper waveform shows the core voltage deviating from
its no-load setting of 1.72V to a minimum of about 1.62V
upon the application of current. The voltage then settles to its
1.67V full-load setting. On load removal, the core voltage
peaks at a level of 1.78V before settling again to its 1.72V
no-load setting. Although the specified operating range
allows deviations as low as 1.60V and as high as 1.85V, a
minimum of 20mV is reserved to allow for the reference
tolerance and the tolerances of other components that
contribute to the overall system accuracy.
The close up in Figure 6 shows the core-voltage, inductorcurrent and PWM signals changing in response to the
trailing edge of the transient load current. Again, the duty
cycles immediately decrease to zero, and the inductors
begin shedding load current at the maximum rate. Note that
the inductor currents briefly go negative as the transient
settles. The capacitors are slightly over charged at the end of
the transient, and the discharge path is in the reverse
direction through the inductors.
CORE VOLTAGE,
50mV/DIV
1.7V
CORE VOLTAGE, 50mV/DIV
1.7V
INDUCTOR CURRENTS,
10A/DIV
INDUCTOR CURRENTS, 10A/DIV
0A
PWM1, 10V/DIV
0V
0A
0V
0V
0V
PWM1, 10V/DIV
PWM2, 10V/DIV
PWM2, 10V/DIV
5µs/DIV
FIGURE 6. TRANSIENT-RESPONSE TRAILING EDGE
Overcurrent Protection
20µs/DIV
FIGURE 4. HIP6302EVAL1 TRANSIENT RESPONSE
Figure 5 is a close-up showing the core-voltage, inductorcurrent and PWM signals responding at the leading edge of
the transient load current. The PWM signals increase to their
maximum duty cycle of 75% on the first pulse following the
start of the transient. The inductor currents begin to increase
immediately and are carrying all of the load within 10µs. The
very fast transient response is due to the precision 18MHz
error amplifier and optimal compensation of the control loop.
When the current out of either ISEN pin exceeds 82µA, the
HIP6302 detects an overcurrent condition and responds by
placing the PWM outputs into a high-impedance state. This
signals the HIP6601 to turn off both upper and lower
MOSFETs in order to remedy the overcurrent condition.This
behavior is seen in Figure 7 where PWM1 goes immediately to
2.5VDC when the output current reaches approximately 50A.
The output voltage then quickly falls to zero.
1.7V
OUTPUT CURRENT,
20A/DIV
CORE VOLTAGE, 50mV/DIV
0A
INDUCTOR CURRENTS,
10A/DIV
CORE VOLTAGE,
500mV/DIV
0V
PWM1, 5V/DIV
0A
PWM1, 10V/DIV
0V
0V
PWM2, 10V/DIV
50µs/DIV
0V
5µs/DIV
FIGURE 5. TRANSIENT-RESPONSE LEADING EDGE
3
FIGURE 7. OVERCURRENT BEHAVIOR
Application Note AN9888
After the initial over-current trip, the HIP6302 waits for a
period of time equal to 2048/fSW (fSW is the switching
frequency) before initiating a soft-start cycle. If the over-load
condition remains, another over-current trip will occur before
the end of the soft-start sequence. This repetitive overcurrent cycling is illustrated in Figure 8, and will continue
indefinitely unless the fault is cleared or power to the
converter is removed. Because of the wait period, the worst
case power delivered during overcurrent cycling is equal to
45% of the power delivered during normal operation at full
load. Therefore, indefinite over-current cycling does not
create a thermal problem for the circuit.
Summary
The HIP6302EVAL1 is intended to provide a convenient
platform to evaluate the performance of the HIP6302 HIP6601A chip set in the specific implementation indicated
in Table 1. The design demonstrates a favorable trade off
between low cost, high efficiency, and small footprint. The
following pages include schematic, bill of materials, and
layout drawings to facilitate implementation of this solution.
The evaluation board is simple and convenient to operate,
and test points are available to evaluate the most commonly
tested parameters. Example waveforms are given for
reference.
The HIP6302 and HIP6601A provide a versatile 2-phase
power solution for low-voltage applications from 25A to
approximately 40A, and together they result in the most
effective solution available.
OUTPUT CURRENT, 20A/DIV
References
0A
For Intersil documents available on the internet, see web site
http://www.intersil.com/
Intersil Technical Support 1 (888) INTERSIL
CORE VOLTAGE,
500mV/DIV
[1] HIP6302 Data Sheet, Intersil Corporation, Power
Management Products Division, 2000.
(http://www.intersil.com/).
0V
[2] HIP6601A, HIP6603A Data Sheet, Intersil Corporation,
Power Management Products Division, 2000.
5ms/DIV
FIGURE 8. OVERCURRENT BEHAVIOR
[3] HIP6602A Data Sheet, Intersil Corporation, Power
Management Products Division, 2000.
Efficiency
Figure 9 shows the efficiency versus current plot for the
HIP6302EVAL1 for 5A through 35A. The measurements
were made at room temperature with natural convection
cooling only..
90
EFFICIENCY (%)
85
80
75
70
5
10
15
20
25
CURRENT (AMPERES)
FIGURE 9. EFFICIENCY vs CURRENT
4
30
35
Application Note AN9888
Schematic
5VIN
L1
1µF
C6
1µF
12VIN
6
9
VCC
PVCC
16
C7
0.1µF
7
VCC
PWM1
GND
13
3
BOOT 1
UGATE
HIP6601
1
2
3
4
5
VID4
VID3
ISEN1
VID2
14
4 U1
TP2
TP1
VID1
C9
1µF
VID0
C12
1µF
HIP6302
15
R1
2.15kΩ
PGOOD
PWM2
12
3
C10
100µF
C2
1000µF
C8
0.1µF
6
7 2
VCC
PVCC
JP1
C1
1000µF
L2
450nH
Q2
HUF76139
5
LGATE
GND
C5
100µF
Q1
HUF76139
8
PWM PHASE
TP3
C4
1µF
C3
0.1µF
2
BOOT 1
UGATE
PWM PHASE
HIP6601
TP4
Q3
HUF76139
8
L3
450nH
Q4
HUF76139
LGATE 5
GND
TP6
4 U3
FS/DIS
R3
107kΩ
ISEN2
COMP
FB
VSEN
6
7
10
R4
14.0kΩ
R5
1.00kΩ
11
TP5
R2
2.15kΩ
TP7
C11
2.2nF
C13-C17
22µF
R6
45.3kΩ
C18-C21
560µF
JP2
HO
R9
1kΩ
RED
U4
HIP2100
Q6
HUF76129
GREEN
TP11
CR1
Q5
2N7002
R15
0.200Ω
3
R14, R16
0.100Ω
POWER GOOD INDICATOR
4
HS
7
VSS
LO
8
HI
R7
1kΩ
6
LI
Q7
HUF76129
R8
10kΩ
2
VDD
1
HB
C48
1µF
SW1
R17
46.4kΩ
ON
R18
400Ω
Q8
2N7002
C49
10µF
R12
R10
D1
BAV99
1.50kΩ
D2
BAV99
1.50kΩ
R13
R11
619Ω
619Ω
TRANSIENT GENERATOR
5
OFF
Application Note AN9888
Bill of Materials
QTY
REFERENCE
DESCRIPTION
1
CR1
RED/GREEN LED
2
C1, C2
1000µF, 10V, Aluminum Capacitor
3
C3, C7, C8
0.1µF, 25V, Y5V, Ceramic Capacitor
5
C4, C6, C9, C12, C48
1.0µF, 25V, Y5V, Ceramic Capacitor
2
C5, C10
100µF, 16V, OS-CON Capacitor
1
C11
2.2nF, 50V, X7R, Ceramic Capacitor
PACKAGE
VENDOR
PART NO.
SMT
Lumex
SSL-LXA3025IGC
Radial
Panasonic
EEUFC1A102L
0603
Various
0805
Various
Radial
Sanyo
0603
Various
5
C13-C17, C49
10µF, 10V, X7R, Ceramic Capacitor
1206
Various
4
C19, C20, C22, C23
560µF, 4V, OS-CON Capacitor
Radial
Sanyo
2
C18, C21
Spare
Radial
24
C24-C47
Spare
1206
2
D1, D2
Dual Diode
1
JP1
5-Position Jumper Header
JP2
1-Position Header
5
1
4SP560M
SOT23
Various
BAV99
100mil Centers
Berg
68000-236
Berg
71363-102
100mil Centers
Berg
68000-236
Berg
71363-102
Jumpers
1
16SPS100M
Jumper
1
J1
ATX Power Header
Berg
39-29-9203
2
J2, J3
Female Banana Connector, Red
Johnson
Components
111-0702-001
1
J4
Female Banana Connector, Black
Johnson
Components
111-0703-001
2
J5, J6
Terminal Connector
Burndy
KPA8CTP
TTIG0803-127
1
L1
1uH, T30-26, 6T AWG18
400x300mil
Falco
2
L2, L3
450nH, T60-8/90, 5T AWG14
700x500mil
Falco
TTIB1506-478
4
Q1, Q2, Q3, Q4
Power MOSFETs
TO-263AB
Intersil
HUF76139S3S
2
Q5, Q8
General Purpose MOSFET
SOT23
Various
2N7002
2
Q6, Q7
Power MOSFET
TO-252AA
Intersil
HUF76129D3S
2
R1, R2
Resistor, 2.15kΩ, 1%, 1/10W
0603
Various
1
R3
Resistor, 107kΩ, 1%, 1/10W
0603
Various
1
R4
Resistor, 14.0kΩ, 1%, 1/10W
0603
Various
1
R5
Resistor, 1.00kΩ, 1%,1/10W
0603
Various
Various
1
R6
Resistor, 45.3kΩ, 1%, 1/10W
0603
2
R7, R9
Resistor, 1.0kΩ, 5%, 1/8W
0805
Various
1
R8
Resistor, 10kΩ, 5%, 1/10W
0603
Various
2
R10, R12
Resistor, 1.50kΩ, 1%, 1/8W
0805
Various
2
R11, R13
Resistor, 619Ω, 1%, 1/8W
0805
Various
2
R14, R16
Resistor, 0.100Ω, 1%, 1W
2512
Vishay
WSL2512R100FB43
1
R15
Resistor, 0.200Ω, 1%, 1W
2512
Vishay
WSL2512R200FB43
Various
1
R17
Resistor, 46.4kΩ, 1%,1/8W
0805
1
R18
Resistor, 400Ω, 1%, 1/8W
0805
Various
1
SW1
Switch, SPDT
SMT
C&K Components
GT11MSCKE
6
TP1, TP3, TP4, TP5, TP7, TP8 Small Test Point
Jolo
SPCJ-123-01
3
TP2, TP6, TP10
Keystone
1514-2
2
TP9, TP11
Probe Socket
Tektronics
1314353-00
2
U1, U3
Synchronous Buck Driver IC
8-Lead SOIC
Intersil
HIP6601ACB
1
U2
Multiphase Buck Controller IC
16-Lead SOIC
Intersil
HIP6302CB
1
U4
MOSFET Driver IC
8-Lead SOIC
Intersil
HIP2100IB
Large Test Point
6
Application Note AN9888
Layout Drawing - Components
7
Application Note AN9888
Layout Drawing - Top Copper
8
Application Note AN9888
Layout Drawing - Ground Plane
9
Application Note AN9888
Layout Drawing - Power Plane
10
Application Note AN9888
Layout Drawing - Bottom Copper
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
11
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