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Data
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NOT ECOMM (Availab
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232
I S L6
IPM6220
TM
Advanced Triple PWM and Dual Linear
Power Controller for Portable
Applications
The IPM6220 provides a highly integrated power control and
protection solution for five output voltages required in highperformance notebook PC applications. The IC integrates
three fixed frequency pulse-width-modulation (PWM)
controllers and two linear regulators along with monitoring and
protection circuitry into a single 24 lead SSOP package.
The two PWM controllers that regulate the system main 5V
and 3.3V voltages are implemented with synchronousrectified buck converters. Synchronous rectification and
hysteretic operation at light loads contribute to high efficiency
over a wide range of input voltage and load variation.
Efficiency is further enhanced by using the lower MOSFET’s
rDS(ON) as the current sense element. Input voltage feedforward ramp modulation, current-mode control, and internal
feed-back compensation provide fast and stable handling of
input voltage load transients encountered in advanced
portable computer chip sets.
December 2000
FN4903.1
Features
• Provides Five Regulated Voltages
- +5V ALWAYS
- +3.3V ALWAYS
- +5V Main
- +3.3V Main
- +12V
• High Efficiency Over Wide Line and Load Range
- Synchronous Buck Converters on Main Outputs
- Hysteretic Operation at Light Load
• No Current-Sense Resistor Required
- Uses MOSFET’s rDS(ON)
- Optional Current-Sense Resistor for More Precision
• Operates Directly From Battery 5.6 to 22V Input
• Input Undervoltage Lock-Out (UVLO)
• Excellent Dynamic Response
- Voltage Feed-Forward and Current-Mode Control
• Monitors Output Voltages
The third PWM controller is a boost converter that regulates a
resistor selectable output voltage of nominally 12V.
Two internal linear regulators provide +5V ALWAYS and
+3.3V ALWAYS low current outputs required by the notebook
system controller.
TEMP.
RANGE (oC)
IPM6220CA
0 to 70
IPM6220EVAL1
• Separate Shut-Down Pins for Advanced Configuration and
Power Interface (ACPI) Compatibility
• 300kHz Fixed Switching Frequency on Main Outputs
• Thermal Shut-Down Protection
Ordering Information
PART NUMBER
• Synchronous Converters Operate Out of Phase
PKG.
NO.
PACKAGE
24 Ld SSOP
M24.15
Applications
• Mobile PCs
• Hand-Held Portable Instruments
Evaluation Board
Related Literature
Pinout
• Application Note AN9915
IPM6220 (SSOP)
TOP VIEW
24 BOOT1
VBATT 1
3.3V ALWAYS 2
23 UGATE1
BOOT2 3
22 PHASE1
UGATE2 4
21 ISEN1
PHASE2 5
20 LGATE1
5V ALWAYS 6
19 PGND1
LGATE2 7
18 VSEN1
PGND2 8
17 SDWN1
ISEN2 9
16 GATE3
VSEN2 10
15 VSEN3
SDWN2 11
14 GND
PGOOD 12
13 SDWNALL
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 Corporation. | Copyright © Intersil Corporation 2000
Block Diagram
VSEN3
VBATT
GATE3
BOOT1
GND
UVFLT
GATE LOGIC 1
HGDR1
UGATE1
HI
BOOST
CONTROLLER
CLK1
CLK
200ns
RAMP 2
CLK2
CLK1
PHASE1
SHUTOFF
POWER-ON
RESET (POR)
RAMP 1
PWMMD1
POR
DEADTIME
2
REF
VCC
PWM/HYST
BOOT2
LGDR1
PWM ON
UGATE2
HYST ON
GATE LOGIC 2
HGDR2
OVP1
HI
PHASE2
SHUTOFF
-
+
-
VOLTSECOND
CLAMP
+
PWMMD1
R1 = 20K
+
+
-
VBATT
-
+
D Q
R
> Q
REF
VOLTSECOND
CLAMP
∑
-
POR
SDWN1
LDO1
REFERENCE
VCC
+
UVFLT
LGATE2
LGATE1
LGATE1
SDWN
LGATE2
VSEN1
+
+
PWM MODE 2 PWMMD2
R1 = 20K
ISEN1
-
VCC PWM
LATCH 2
OC
LOGIC2
+
-
+
- PWM MODE 1
OC COMP2
2.8V
EA2
ISEN2
∑
+
-
CLK2
REF
HYST COMP2
VSEN2
IPM6220
HYST ON
EA1
+
LO
OVP2
-
OC LOGIC1
Q D
R
Q <
PWM ON
CLK1
+
LGDR2
VSEN1
+
PWM VCC
LATCH 1
DEADTIME
PWM/HYST
VCC
PGND2
PGND1
HYST COMP1
PWMMD2
OC COMP1
LGATE2
LGATE1
LO
OVP1
OVP2
SDWN
OUTPUT
VOLTAGE
MONITOR
REF
3.3V-ALWAYS
PGOOD
FIGURE 1.
AND
SDWN2
SOFT START
LDO2
5V-ALWAYS
2.5V
SDWNALL
IPM6220
Simplified Power System Diagram
VBATT
VBATT
Q1
3.3V ALWAYS
5V ALWAYS
LINEAR
CONTROLLER
5V MAIN
PWM1
CONTROLLER
Q2
LINEAR
CONTROLLER
IPM6220
VBATT
VOLTAGE,
CURRENT
MONITORS
PGOOD
12V BOOST
Q1
3.3V MAIN
PWM2
CONTROLLER
PWM3
CONTROLLER
Q2
FIGURE 2.
Typical Application
+VBATT
PROCESSOR
5V MAIN
SDWN1
VCORE
µP CORE
3.3V MAIN
SDWN2
IPM6220
VI/O
5V ALWAYS
3.3V ALWAYS
C8051
12V
VID CODE
SDWN
PCM
CIA
VCLOCK
ON/OFF
FIGURE 3.
I/O
CLOCK
PGOOD
PGOOD
ENABLE
SDWNALL
3
IPM6210
RESET
IPM6220
I
Absolute Maximum Ratings
Thermal Information
Input Voltage, VBATT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +29.0V
Phase, ISEN and SDWNALL Pins . . . . . . . . . . . GND -0.3V to +29.0V
Boot and UGATE Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +29.0V
BOOT1, 2 with Respect to PHASE1, 2 . . . . . . . . . . . . . . . . . . . +6.5V
All Other Pins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +6.5V
Thermal Resistance (Typical, Note 1)
θJA (oC/W)
θJC (oC/W)
SSOP Package . . . . . . . . . . . . . . . . . .
88
28.5
Maximum Junction Temperature (Plastic Package) . . . . . . . .150oC
Maximum Storage Temperature Range . . . . . . . . . -65oC to 150oC
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . .300oC
(SSOP - Lead Tips Only)
Operating Conditions
Input Voltage, VBATT . . . . . . . . . . . . . . . . . . . . . . . . +5.6V to +22.0V
Ambient Temperature Range. . . . . . . . . . . . . . . . . . . . . 0oC to 70oC
Junction Temperature Range . . . . . . . . . . . . . . . . . . . 0oC to 125oC
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
1. θJA is measured with the component mounted on a low effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
Electrical Specifications
Recommended Operating Conditions, Unless Otherwise Noted. Refer to Block and Simplified Power System
Diagrams, and Typical Application Schematic
PARAMETER
SYMBOL
Input Quiescent Current
TEST CONDITIONS
MIN
TYP
MAX
UNITS
2.0
mA
ICC
SDWN1 = SDWN2 = 5V, SDWNALL = VIN,
Outputs open circuited
-
1.4
Stand-by Current
ICCSB
SDWN1 = SDWN2 = 0V, SDWNALL = VIN,
Outputs open circuited
-
300
µA
Shut-down Current
ICCSN
SDWNALL = 0V
-
<1.0
µA
Input Under-voltage Lock Out
UVLO
Rising VBATT
4.3
4.7
Input Under-voltage Lock Out
UVLO
VBATT, Hysteresis
5.1
150
V
mV
OSCILLATOR
PWM1,2 Oscillator Frequency
Fc1,2
255
300
345
kHz
VREF
-
2.472
-
V
-1.0
-
+1.0
%
-
5
-
µA
REFERENCE AND SOFT START
Internal Reference Voltage
Reference Voltage Accuracy
SDWN1, SDWN2 Output Current During
Start-up
ISS
PWM1 CONVERTER, 5V Main
Output Voltage
VOUT1
Line and Load Regulation
5.0
V
0.0 < IVOUT1 < 5.0A; 5.6V < VBATT < 22.0V
-2
0.5
+2
%
Under-Voltage Shut-Down Level
VUV1
2µs delay, % Feedback Voltage at VSNS1 pin
70
75
80
%
Current Limit Threshold
IOC2
Current from ISNS1 Pin Through RSNS1
90
135
180
µA
Over-Voltage Threshold
VOVP1
2µs delay, % Feedback Voltage at VSNS1 pin
110
115
120
%
Maximum Duty Cycle
DCMAX
SDWN1 > 4.0V
94
%
3.3
V
PWM2 CONVERTER, 3.3V Main
Output Voltage
VOUT2
Line and Load Regulation
0.0 < IVOUT2 < 5.0A; 5.6V < VBATT < 24.0V
-2
0.5
+2
%
Under-Voltage Shut-Down Level
VUV2
2µs delay, % Feedback Voltage at VSNS2 pin
70
75
80
%
Current Limit Threshold
IOC2
Current from ISNS2 Pin Through RSNS2
90
135
180
µA
Over-Voltage Threshold
VOVP2
2µs delay, % Feedback Voltage at VSNS2 pin
110
115
120
%
Maximum Duty Cycle
DCMAX
SDWN2 > 4.0V
4
94
%
IPM6220
Electrical Specifications
Recommended Operating Conditions, Unless Otherwise Noted. Refer to Block and Simplified Power System
Diagrams, and Typical Application Schematic (Continued)
PARAMETER
SYMBOL
Internal Resistance to GND on VSNS2 Pin
TEST CONDITIONS
MIN
RVSNS2
TYP
MAX
UNITS
Ω
66K
PWM1 and PWM2 CONTROLLER GATE DRIVERS
Upper Drive Pull-Up Resistance
R2UGPUP
-
7
12
Ω
Upper Drive Pull-Down Resistance
R2UGPDN
-
4
10
Ω
Lower Drive Pull-Up Resistance
R2LGPUP
-
6
9
Ω
Lower Drive Pull-Down Resistance
R2LGPDN
-
5
8
Ω
PWM 3 CONVERTER
12V Feedback Regulation Voltage
VSEN3
2.472
12V Feedback Regulation Voltage Input
Current
IVSEN3
0.1
Line and Load Regulation
Under-Voltage Shut-Down Level
Over-Voltage Threshold
PWM3 Oscillator Frequency
0.0 < IVOUT3 < 120mA, 4.9V< 5VMain <5.1V
-2
VUV3
2µs delay, % Feedback Voltage at VSNS3 pin
70
VOVP3
2µs delay, % Feedback Voltage at VSNS3 pin
Fc3
85
Maximum Duty Cycle
V
1.0
µA
+2
%
75
80
%
115
120
%
100
115
kHz
33
%
PWM 3 CONTROLLER GATE DRIVERS
Pull-Up Resistance
R3GPUP
6
12
Ω
Pull-Down Resistance
R3GPDN
6
12
Ω
5V and 3.3V ALWAYS
Linear Regulator Accuracy
PWM1, 5V Output OFF (SDWN1 = 0V);
5.6V < VBATT < 22V; 0 < ILOAD < 50mA
-2.0
0.5
+2.0
%
5V ALWAYS Output Voltage Regulation
PWM1, 5V Output ON (SDWN1 = 5V);
0 < ILOAD < 50mA
-3.3
1.0
+2.0
%
Maximum Output Current
Combined 5V ALWAYS and 3.3V ALWAYS
50
Current Limit
Combined 5V ALWAYS and 3.3V ALWAYS
100
5V ALWAYS Under-Voltage Shut-Down
Bypass Switch rDS(ON)
PWM1, 5V Output ON (SDWN1 = 5V)
mA
180
mA
75
%
1.3
Ω
POWER GOOD AND CONTROL FUNCTIONS
Power Good Threshold for PWM1 and
PWM2 Output Voltages
PGOOD Leakage Current
IPGLKG
PGOOD Voltage Low
VPGOOD
VPULLUP = 5.0V
IPGOOD = -4mA
-14
-12
-10
%
-
-
1.0
µA
0.2
0.5
V
10
µs
SDWN1, 2, - Low (Off)
0.8
V
SDWN1, 2, - High (On)
4.3
V
SDWNALL - High (On)
2.4
V
40
mV
Over-Temperature Shutdown
150
oC
Over-Temperature Hysteresis
25
oC
PGOOD Minimum Pulse Width
TPGmin
SDWNALL - Low (Off)
SDWNALL, Hysteresis
5
IPM6220
Functional Pin Descriptions
VBATT (Pin 1)
Supplies all the power necessary to operate the chip. The IC
starts to operate when the voltage on this pin exceeds 4.7V
and stops operating when the voltage on this pin drops
below approximately 4.5V. Also provides battery voltage to
the oscillator for feed-forward rejection to input voltage
variations.
3.3V ALWAYS (Pin 2)
Output of 3.3V ALWAYS linear regulator.
5V ALWAYS (Pin 6)
Output of 5V ALWAYS linear regulator or the +5V Main
output. If the +5V Main output is enabled, it is switched
internally from the VSEN1 pin to the 5V ALWAYS output.
This improves efficiency and reduces the power dissipation
in the controller.
BOOT1, BOOT2 (Pins 24 and 3)
controllers. The PGOOD, overvoltage protection (OVP) and
undervoltage shutdown circuits use these signals to
determine output-voltage status and/or to initiate
undervoltage shut down. The VSEN1 input is also switched
internally to the 5V ALWAYS output if the +5V Main output is
enabled.
SDWNALL (Pin 13)
This pin provides enable/disable function for all outputs. The
chip is completely disabled when this pin is pulled to ground.
When this pin is pulled high, the 5V ALWAYS and 3.3
ALWAYS outputs are on and the other outputs are enabled.
The state of 5V Main and 3.3V Main outputs depend on the
voltage on SDWN1 and SDWN2 respectively. See Table 1.
SDWN1 (Pin 17)
This pin provides enable/disable function and soft-start for
the PWM1, 5V Main, output. The output is enabled when this
pin is high and SDWNALL is also high. The 5V output is held
off when the pin is pulled to the ground.
SDWN2 (Pin 11)
Power is supplied to the upper MOSFET drivers of PWM1
and PWM2 converters via the BOOT pins. Connect these
pins to the respective junctions of bootstrap capacitors with
the cathodes of the bootstrap diodes. Anodes of the
bootstrap diodes are connected to pin 6, 5V ALWAYS.
This pin provides enable/disable function and soft-start for
PWM2, 3.3V Main, output. The output is enabled when this
pin is high and SDWNALL is also high. The 3.3V output is
held off when the pin is pulled to the ground.
UGATE1, UGATE2 (Pins 23 and 4)
VSEN3 (Pin 15)
These pins provide the gate drive for the upper MOSFETs.
Connect UGATE pins to the respective PWM converter’s
upper MOSFET gate.
This input pin is the voltage feedback signal for PWM3, the
boost controller. The boost controller regulates this point to a
voltage divided level of 2.472 VDC. The PGOOD,
overvoltage protection (OVP) and undervoltage shutdown
circuits use this signal to determine output-voltage status
and/or to initiate undervoltage shut down.
PHASE1, PHASE2 (Pins 22 and 5)
The phase nodes are the junctions of the upper MOSFET
sources, output filter inductors, and lower MOSFET drains.
Connect the PHASE pins directly to the respective PWM
converter’s lower MOSFET drain.
ISEN1, ISEN2 (Pins 21 and 9)
These pins are used to monitor the voltage drop across the
lower MOSFETs for current feedback and current-limit
protection. For more precise current detection, these inputs
can be connected to optional current sense resistors placed
in series with the sources of the lower MOSFETs.
This pin can also be used to independently disable the
PWM3 controller. Connect this pin to 5V ALWAYS if the
boost converter is not populated in your design.
GATE3 (Pin 16)
This pin drives the gate of the boost MOSFET.
PGOOD (Pin 12)
These pins provide the gate drive for the lower MOSFETs.
Connect the lower MOSFET gate of each converter to the
corresponding pin.
PGOOD is an open drain output used to indicate the status
of the PWM converters’ output voltages. This pin is pulled
low when any of the outputs except PWM3 (12V) is not
within -10% of respective nominal voltages, or when PWM3
(12V) is not within its undervoltage and overvoltage
thresholds.
PGND1, PGND2 (Pins 19 and 8)
GND (Pin 14)
These are the lower MOSFET gate drive return connection
for PWM1 and PWM2 converters, respectively. Tie each
lower MOSFET source directly to the corresponding pin.
Signal ground for the IC. All voltage levels are measured
with respect to this pin.
LGATE1, LGATE 2 (Pins 20 and 7)
VSEN1, VSEN2 (Pins 18, 10)
These pins are connected to the main outputs and provide
the voltage feedback signal for the respective PWM
6
General Description
The IPM6220 addresses the system electronics power
needs of modern notebook and sub-notebook PCs. The IC
integrates control circuits for two synchronous buck
IPM6220
converters for 5V Main and 3.3V Main buses, two linear
regulators for 3.3V ALWAYS and 5V ALWAYS, and a 12V
boost converter.
The two synchronous converters operate out of phase to
substantially reduce the input-current ripple, minimizing input
filter requirements, minimizing battery heating and
prolonging battery life.
The 12V boost controller uses a 100kHz clock derived from
the main clock. This controller uses leading edge modulation
with the maximum duty cycle limited to 33%.
Rcs
Vo
RSNS = ------------------  Iocdc + ----------------------------------------- – 100
135µA 
L × 2 × 300kHz
VIN = 10.8V
IL3.3V (2A/DIV.)
5A
3.3V PHASE (10V/DIV.)
0 A, V
5A
The chip has three input control lines SDWN1, SDWN2 and
SDWNALL. These are provided for Advanced Configuration
and Power Interface (ACPI) compatibility. They turn on and
off all outputs, as well as provide independent control of the
3.3V Main and +5V Main outputs.
To maximize efficiency for the 5V Main and 3.3V Main outputs,
the current-sense technique is based on the lower MOSFET
rDS(ON). Light-load efficiency is further enhanced by a
hysteretic mode of operation which is automatically engaged at
light loads when the inductor current becomes discontinuous.
3.3V Main and 5V Main Architecture
These main outputs are generated from the unregulated
battery input by two independent synchronous buck
converters. The IC integrates all the components required
for output voltage setpoint and feedback compensation,
significantly reducing the number of external components,
saving board space and parts cost.
The buck PWM controllers employ a 300kHz fixed frequency
current-mode control scheme with input voltage feedforward ramp programming for better rejection of input
voltage variations.
Figure 4 shows the out-of-phase operation for the 3.3V Main
and 5V Main outputs. The phase node is the junction of the
upper MOSFET, lower MOSFET and the output inductor.
The phase node is high when the upper MOSFET is
conducting and the inductor current rises accordingly. When
the phase node is low, the lower MOSFET is conducting and
the inductor current is ramping down as shown.
Current Sensing and Current Limit Protection
Both PWM converters use the lower MOSFET on-state
resistance, rDS(ON), as the current-sensing element. This
technique eliminates the need for a current sense resistor
and the associated power losses. If more accurate current
protection is desired, current sense resistors may be used in
series with the lower MOSFETs’ source.
To set the current limit, place a resistor, RSNS, between the
ISEN inputs and the drain of the lower MOSFET (or optional
current sense resistor). The required value of the RSNS
resistor is determined from the following equation:
7
IL5V (2A/DIV.)
0 A, V
5V PHASE (10V/DIV.)
1µs/DIV.
FIGURE 4. OUT OF PHASE OPERATION
where IOCDC is the desired DC overcurrent limit; RCS is
either the rDS(ON) of the lower MOSFET, or the value of the
optional current-sense resistor, Vo is the output voltage and L
is the output inductor. Also, the value of RCS should be
specified for the expected maximum operating
temperature.
The sensed voltage, and the resulting current out of the
ISEN pin through RSNS, is used for current feedback and
current limit protection. This is compared with an internal
current limit threshold. When a sampled value of the output
current is determined to be above the current limit
threshold, the PWM drive is terminated and a counter is
initiated. This limits the inductor current build-up and
essentially switches the converter into current-limit mode. If
an overcurrent is detected between 26µs to 53µs later, an
overcurrent shutdown is initiated. If during the 26µs to 53µs
period, an overcurrent is not detected, the counter is reset
and sampling continues as normal.
This current limit scheme has proven to be very robust in
applications like portable computers where fast inductor
current build-up is common due to a large difference
between input and output voltages and a low value of the
inductor.
Light-Load (Hysteretic) Operation
In the light-load (hysteretic) mode the output voltage is
regulated by the hysteretic comparator which regulates the
output voltage by maintaining the output voltage ripple as
shown in Figure 5. In Hysteretic mode, the inductor current
flows only when the output voltage reaches the lower limit of
the hysteretic comparator and turns off at the upper limit.
Hysteretic mode saves converter energy at light loads by
supplying energy only at the time when the output voltage
requires it. This mode conserves energy by reducing the
power dissipation associated with continuous switching.
IPM6220
During the time between inductor current pulses, both the
upper and lower MOSFETs are turned off. This is referred to
as ‘diode emulation mode’ because the lower MOSFET
performs the function of a diode. This diode emulation mode
prevents the output capacitor from discharging through the
lower MOSFET when the upper MOSFET is not conducting.
The gate drive is synchronized to the main clock, so the outof-phase timing is maintained in hysteretic mode. Such a
scheme insures a seamless transition between the
operational modes.
VOUT
t
IL
t
PHASE
COMP
HYSTERETIC
PWM
The other mechanism for changing from hysteretic to PWM
is due to a sudden increase in the output current. This step
load causes an instantaneous decrease in the output voltage
due to the voltage drop on the output capacitor ESR. If the
decrease causes the output voltage to drop below the
hysteretic regulation level, the mode is changed to PWM on
the next clock cycle. This insures the full power required by
the increase in output current.
t
1 2 3 4 5 6 7 8
MODE
OF
OPERATION
The mode change from hysteretic to PWM can be caused by
one of two events. One event is the same mechanism that
causes a PWM to hysteretic transition. But instead of looking
for eight consecutive positive occurrences on the phase
node, it is looking for eight consecutive negative
occurrences on the phase node. The operation mode will be
changed from hysteretic to PWM when these eight
consecutive pulses occur. This transition technique prevents
jitter of the operation mode at load levels close to boundary.
IL
t
t
FIGURE 5. REGULATION IN HYSTERETIC MODE
Operation-Mode Control
The mode-control circuit changes the converter’s mode of
operation based on the voltage polarity of the phase node
when the lower MOSFET is conducting and just before the
upper MOSFET turns on. For continuous inductor current,
the phase node is negative when the lower MOSFET is
conducting and the converters operate in fixed-frequency
PWM mode as shown in Figure 6. When the load current
decreases to the point where the inductor current flow
through the lower MOSFET in the ‘reverse’ direction, the
phase node becomes positive, and the mode is changed to
hysteretic.
A phase comparator handles the timing of the phase node
voltage sensing. A low level on the phase comparator output
indicates a negative phase voltage during the conduction
time of the lower MOSFET. A high level on the phase
comparator output indicates a positive phase voltage.
When the phase node is positive (phase comparator high),
at the end of the lower MOSFET conduction time, for eight
consecutive clock cycles, the mode is changed to hysteretic
as shown in Figure 6. The dashed lines indicate when the
phase node goes positive and the phase comparator output
goes high. The solid vertical lines at 1,2,...8 indicate the
sampling time, of the phase comparator, to determine the
polarity (sign) of the phase node. At the transition between
PWM and hysteretic mode both the upper and lower
MOSFETs are turned off. The phase node will ‘ring’ based
on the output inductor and the parasitic capacitance on the
phase node and settle out at the value of the output voltage.
8
PHASE
NODE
t
1
2
3
4
5
6
7
8
PHASE
COMP
t
MODE
OF
OPERATION
PWM
HYSTERETIC
t
FIGURE 6. MODE CONTROL WAVEFORMS
Gate Control Logic
The gate control logic translates generated PWM control
signals into the MOSFET gate drive signals providing
necessary amplification, level shifting and shoot-through
protection. Also, it has functions that help optimize the IC
performance over a wide range of operational conditions.
Since MOSFET switching time can vary dramatically from
type to type and with the input voltage, the gate control logic
provides adaptive dead time by monitoring the gate-tosource voltages of both upper and lower MOSFETs. The
lower MOSFET is not turned on until the gate-to-source
voltage of the upper MOSFET has decreased to less than
approximately 1 volt. Similarly, the upper MOSFET is not
turned on until the gate-to-source voltage of the lower
MOSFET has decreased to less than approximately 1 volt.
This allows a wide variety of upper and lower MOSFETs to
be used without a concern for simultaneous conduction, or
shoot-through.
IPM6220
3.3V Main and 5V Main Soft Start, Sequencing and
Stand-by
See Table 1 for the output voltage control algorithm. The 5V
Main and 3.3V Main converters are enabled if SDWN1 and
SDWN2 are high and SDWNALL is also high. The stand-by
mode is defined as a condition when SDWN1 and SDWN2 are
low and the PWM converters are disabled but SDWNALL is
high (3.3V ALWAYS and 5V ALWAYS outputs are enabled). In
this power saving mode, only the low power micro-controller
and keyboard may be powered.
TABLE 1. OUTPUT VOLTAGE CONTROL
SDWN2
3V AND 5V
ALWAYS 5V MAIN 3V MAIN
0
X
X
OFF
OFF
OFF
1
0
0
ON
OFF
OFF
1
1
0
ON
ON
OFF
1
0
1
ON
OFF
ON
1
1
1
ON
ON
ON
Soft start of the 3.3V Main and 5V Main converters is
accomplished by means of capacitors connected from pins
SDWN1 and SDWN2 to ground. In conjunction with 5µA
internal current sources, they provide a controlled rise of the
3.3V Main and 5V Main output voltages. The value of the
soft-start capacitors can be calculated from the following
expression.
5µA × Tss
Css = ---------------------------3.5V
12V Converter Architecture
The 12V boost converter generates its output voltage from
the 5V Main output. An external MOSFET, inductor, diode
and capacitor are required to complete the circuit. The
output signal is fed back to the controller via an external
resistive divider. The boost controller can be disabled by
connecting the VSEN3 pin to 5V ALWAYS.
The control circuit for the 12V converter consists of a 3:1
frequency divider which drives a ramp generator and resets
a PWM latch as shown in Figure 8. The width of the CLK/3
pulses is equal to the period of the main clock, limiting the
duty cycle to 33%. The output of a non-inverting error
amplifier is compared with the rising ramp voltage. When the
ramp voltage becomes higher than the error signal, the
PWM comparator sets the latch and the output of the gate
driver is pulled high providing leading edge, voltage mode
PWM. The falling edge of the CLK/3 pulses resets the latch
and pulls the output of the gate driver low.
VSEN3
By varying the values of the soft-start capacitors, it is possible
to provide sequencing of the main outputs at start-up.
Figure 7 shows the soft-start initiated by the SDWNALL pin
being pulled high with the Vbatt input at 10.8V and the
resulting 3.3V Main and 5V Main outputs.
+
Where Tss is the desired soft-start time.
-
REF
EA3
GATE3
PWM
PWM
COMPARATOR LATCH 3
S Q
RAMP
R Q
+
SDWNALL SDWN1
and 5V ALWAYS outputs. With the 3.3V Main and 5V Main
outputs enabled, at T1, the internal 5µA current sources start
charging the soft start capacitors on the SDWN1 and
SDWN2 pins. At T2 the outputs begin to rise and because
they both have the same value of soft-start capacitors,
0.022µF, they both reach regulation at the same time, T3.
The soft-start capacitors continue to charge and are
completely charged at T4.
CLK/3
CLK
DIVIDER
3:1
CLK/3
RAMP
GENERATOR
CLK
t
VIN = 10.8V
CLK/3
SDWNALL,10V/DIV.
t
RAMP
VEA3
SDWN2, 2V/DIV.
t
3.3VOUT , 2V/DIV.
GATE3
t
0V
FIGURE 8. 12V BOOST OPERATION
SDWN1, 2V/DIV.
The 33% maximum duty cycle of the converter guarantees
discontinuous inductor current and unconditional stability
over all operating conditions.
5VOUT , 2V/DIV.
0V
4ms/DIV.
T0 T1
T2
T3
T4
FIGURE 7. SOFT START ON 3.3V AND 5V OUTPUTS
While the SDWNALL pin is held low, prior to T0, all outputs
are off. Pulling SDWNALL high enables the 3.3V ALWAYS
9
The boost converter with the limited duty cycle and
discontinuous inductor current can deliver to the load a
limited amount of power before the output voltage starts to
drop. When the duty cycle has reached DMAX, the control
IPM6220
loop is operating open circuit and the output voltage varies
with the output load resistance, Ro, as given by:
Ro
Vo = Vin × Dmax  -------------------
 2 ( LxF )
Where Vin is the 5V Main voltage, Dmax = 0.33, L is the
value of the boost inductor, L3, and F = 100kHz. This
provides automatic output current limiting. When the
maximum duty cycle has been reached and for a given
inductor, a further reduction in Ro by one-half will pull the
output voltage down to 0.707 of nominal and cause an
under-voltage condition.
The 12V converter starts to operate at the same time as the
5V Main converter. The rising voltage on the 5V Main output
and the 33% duty cycle limit provides a similar soft-start, as
the 5V Main, for the 12V output.
MOSFET is turned off and the lower MOSFET is turned on.
This ‘soft-crowbar’ condition will be maintained until the
output voltage returns to the regulation window and then
normal operation will continue.
This ‘soft-crowbar’ and monitoring of the output, prevents the
output voltage from ringing negative as the inductor current
flows in the ‘reverse’ direction through the lower MOSFET
and output capacitors.
Over-Temperature Protection
The IC incorporates an over-temperature protection circuit
that shuts all the outputs down when the die temperature
exceeds 150oC. Normal operation is automatically restored
when the die temperature cools to 125oC.
Component Selection Guidelines
Output Capacitor Selection
3V ALWAYS, 5V ALWAYS Linear
Regulators
The 3.3V ALWAYS and 5V ALWAYS outputs are derived
from the battery voltage and are the first voltages available
in the notebook when power on is initiated. The 5V ALWAYS
output is generated directly from the battery voltage by a
linear regulator. It is used to power the system microcontroller and to internally power the chip and the gate
drivers. The 3.3V ALWAYS output is generated from the 5V
ALWAYS output and may be used to power the keyboard
controller or other peripherals. The combined current
capability of these outputs is 50mA. When the 5V Main
output is greater than it’s undervoltage level, it is switched to
the 5V ALWAYS output via an internal 1.3Ω MOSFET
switch. Simultaneously, the 5V ALWAYS linear regulator is
disabled to prevent excessive power dissipation.
The rise time of the 5V ALWAYS is determined by the value
of the output capacitance on the 5V and 3.3V ALWAYS
outputs. The internal regulator is current limited to about
180mA, so the start up time is approximately:
5V
t = C OUT × ------------------180mA
Where COUT is the sum of the capacitances on the 5V and
3.3V ALWAYS outputs.
Power Good Status
The IPM6220 monitors all the output voltages except for the
3.3V ALWAYS. A single power-good signal, PGOOD, is
issued when soft-start is completed and all monitored
outputs are within 10% of their respective set points. After
the soft-start sequence is completed, undervoltage
protection latches the chip off when any of the monitored
outputs drop below 75% of its set point.
A ‘soft-crowbar’ function is implemented for an overvoltage
on the 3.3V Main or 5V Main outputs. If the output voltage
goes above 115% of their nominal output level, the upper
10
The output capacitors for each output have unique
requirements. In general, the output capacitors should be
selected to meet the dynamic regulation requirements
including ripple voltage and load transients.
3.3V Main and 5V Main PWM Output Capacitors
Selection of the output capacitors is also dependent on the
output inductor so some inductor analysis is required to
select the output capacitors.
One of the parameters limiting the converter’s response to a
load transient is the time required for the inductor current to
slew to it’s new level. Given a sufficiently fast control loop
design, the IPM6220 will provide either 0% or 94% duty
cycle in response to a load transient. The response time is
the time interval required to slew the inductor current from an
initial current value to the load current level. During this
interval the difference between the inductor current and the
transient current level must be supplied by the output
capacitor(s). Minimizing the response time can minimize the
output capacitance required. Also, if the load transient rise
time is slower than the inductor response time, as in a hard
drive or CD drive, this reduces the requirement on the output
capacitor.
The maximum capacitor value required to provide the full,
rising step, transient load current during the response time of
the inductor is:
I TRAN
L O × I TRAN
C OUT = ---------------------------------------------- × -------------------( V IN – V OUT ) × 2 DV OUT
Where: COUT is the output capacitor(s) required, LO is the
output inductor, ITRAN is the transient load current step, VIN
is the input voltage, VOUT is output voltage, and ∆VOUT is
the drop in output voltage allowed during the load transient.
High frequency capacitors initially supply the transient
current and slow the load rate-of-change seen by the bulk
capacitors. The bulk filter capacitor values are generally
IPM6220
determined by the ESR (Equivalent Series Resistance) and
voltage rating requirements as well as actual capacitance
requirements. The output voltage ripple is due to the
inductor ripple current and the ESR of the output capacitors
as defined by:
expression is given in the capacitor selection section and the
ripple current is approximated by the following equation:
V IN – V OUT V OUT
∆I L = -------------------------------- × ---------------V IN
FS × L
Input Capacitor Selection
where, ∆IL is calculated in the Inductor Selection section.
High frequency decoupling capacitors should be placed as
close to the power pins of the load as physically possible. Be
careful not to add inductance in the circuit board wiring that
could cancel the usefulness of these low inductance
components. Consult with the manufacturer of the load
circuitry for specific decoupling requirements.
Use only specialized low-ESR capacitors intended for
switching-regulator applications, at 300kHz, for the bulk
capacitors. In most cases, multiple electrolytic capacitors of
small case size perform better than a single large case
capacitor.
The stability requirement on the selection of the output
capacitor is that the ‘ESR zero’, fZ, be between 1.2kHz and
30kHz. This range is set by an internal, single compensation
zero at 6kHz. The ESR zero can be a factor of five on either
side of the internal zero and still contribute to increased
phase margin of the control loop. Therefore:
1
C OUT = ------------------------------------------2 × π × ESR × f Z
In conclusion, the output capacitors must meet three criteria: By
varying the values of the soft-start capacitors, it is possible to
provide sequencing of the main outputs at start-up.
1. They must have sufficient bulk capacitance to sustain the
output voltage during a load transient while the output
inductor current is slewing to the value of the load
transient
2. The ESR must be sufficiently low to meet the desired
output voltage ripple due to the output inductor current,
and
3. The ESR zero should be placed, in a rather large range,
to provide additional phase margin.
3.3V ALWAYS and 5V ALWAYS Output Capacitors
The output capacitors for the linear regulators insure stability
and provide dynamic load current. The 3.3V ALWAYS and
the 5V ALWAYS linear regulators should have, as a
minimum, 10µF capacitors on their outputs.
3.3V Main and 5V Main PWM Output Inductor
Selection
The PWM converters require output inductors. The output
inductor is selected to meet the output voltage ripple
requirements. The inductor value determines the converter’s
ripple current and the ripple voltage is a function of the ripple
current and output capacitor(s) ESR. The ripple voltage
11
The important parameters for the bulk input capacitor(s) are
the voltage rating and the RMS current rating. For reliable
operation, select bulk input capacitors with voltage and
current ratings above the maximum input voltage and largest
RMS current required by the circuit. The capacitor voltage
rating should be at least 1.25 times greater than the
maximum input voltage and 1.5 times is a conservative
guideline.
The AC RMS input current varies with load as shown in
Figure 9. Depending on the specifics of the input power and
it’s impedance, most (or all) of this current is supplied by the
input capacitor(s). Figure 9 also shows the advantage of
having the PWM converters operating out of phase. If the
converters were operating in phase, the combined RMS
current would be the algebraic sum, which is a much larger
value as shown. The combined out-of-phase current is the
square root of the sum of the square of the individual
reflected currents and is significantly less than the combined
in-phase current.
INPUT RMS CURRENT
V RIPPLE = ∆I L × ESR
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
IN PHASE
OUT OF PHASE
5V
3.3V
0
1
2
3
3.3V AND 5V LOAD CURRENT
4
5
FIGURE 9. INPUT RMS CURRENT vs LOAD
Use a mix of input bypass capacitors to control the voltage
ripple across the MOSFETs. Use ceramic capacitors for the
high frequency decoupling and bulk capacitors to supply the
RMS current. Small ceramic capacitors can be placed very
close to the upper MOSFET to suppress the voltage induced
in the parasitic circuit impedances.
For board designs that allow through-hole components, the
Sanyo OS-CON® series offer low ESR and good
temperature performance.
For surface mount designs, solid tantalum capacitors can be
used, but caution must be exercised with regard to the
capacitor surge current rating. These capacitors must be
capable of handling the surge-current at power-up. The TPS
series available from AVX is surge current tested.
OS-CON® is a registered trademark of Sanyo Electric Company, Ltd. (Japan)
IPM6220
+12V Boost Converter Inductor Selection
The inductor value is chosen to provide the required output
power to the load.
Vinmin 2 × Dmax 2 × Ro
Lmax = ---------------------------------------------------------------2 × Vo 2 × F
where, Vinmin is the minimum input voltage, 4.9V; Dmax =
1/3, the maximum duty cycle; Ro is the minimum load
resistance; Vo is the nominal output voltage and F is the
switching frequency, 100kHz.
+12V Boost Converter Output Capacitor Selection
The total capacitance on the 12V output should be chosen
appropriately, so that the output voltage will be higher than
the undervoltage limit (9V) when the 5V Main soft-start time
has elapsed. This will avoid triggering of the 12V
undervoltage protection.
The maximum value of the boost capacitor, Comax that will
charge to 9V in the soft start time, Tss , is shown below,
where L is the value of the boost inductor.
Tss
Comax = ---------- × 0.115µF
L
The output capacitor ESR and the boost inductor ripple
current determines the output voltage ripple. The ripple
voltage is given by:
V RIPPLE = ∆I L × ESR
and the maximum ripple current, ∆IL, is given by:
5V
∆I L = ------- × 3.3 µ
L
where L is the boost inductor calculated above, 5V is the
boost input voltage and 3.3µ is the maximum on time for the
boost MOSFET.
MOSFET Considerations
The logic level MOSFETs are chosen for optimum efficiency
given the potentially wide input voltage range and output
power requirements. Two N-channel MOSFETs are used in
each of the synchronous-rectified buck converters for the
PWM1 and PWM2 outputs. These MOSFETs should be
selected based upon rDS(ON) , gate supply requirements,
and thermal management considerations.
The power dissipation includes two loss components;
conduction loss and switching loss. These losses are
distributed between the upper and lower MOSFETs
according to duty cycle (see the following equations). The
conduction losses are the main component of power
dissipation for the lower MOSFETs. Only the upper
MOSFET has significant switching losses, since the lower
device turns on and off into near zero voltage.
The equations assume linear voltage-current transitions and
do not model power loss due to the reverse-recovery of the
lower MOSFET’s body diode. The gate-charge losses are
12
2
I O × r DS ( ON ) × V OUT I O × V IN × t SW × F S
P UPPER = ----------------------------------------------------------- + ---------------------------------------------------V IN
2
2
I O × r DS ( ON ) × ( V IN – V OUT )
P LOWER = -------------------------------------------------------------------------------V IN
dissipated by the IPM6220 and do not heat the MOSFETs.
However, a large gate-charge increases the switching time,
tSW which increases the upper MOSFET switching losses.
Ensure that both MOSFETs are within their maximum
junction temperature at high ambient temperature by
calculating the temperature rise according to package
thermal-resistance specifications.
Layout Considerations
MOSFETs switch very fast and efficiently. The speed with
which the current transitions from one device to another
causes voltage spikes across the interconnecting impedances
and parasitic circuit elements. The voltage spikes can
degrade efficiency, radiate noise into the circuit, and lead to
device overvoltage stress. Careful component layout and
printed circuit design minimizes the voltage spikes in the
converter. Consider, as an example, the turn-off transition of
one of the upper PWM MOSFETs. Prior to turn-off, the upper
MOSFET is carrying the full load current. During the turn-off,
current stops flowing in the upper MOSFET and is picked up
by the lower MOSFET. Any inductance in the switched current
path generates a voltage spike during the switching interval.
Careful component selection, tight layout of the critical
components, and short, wide circuit traces minimize the
magnitude of voltage spikes. See the Application Note
AN9915 for the evaluation board component placement and
the printed circuit board layout details.
There are two sets of critical components in a DC-DC
converter using an IPM6220 controller. The switching power
components are the most critical because they switch large
amounts of energy, and as such, they tend to generate
equally large amounts of noise. The critical small signal
components are those connected to sensitive nodes or
those supplying critical bias currents.
Power Components Layout Considerations
The power components and the controller IC should be
placed first. Locate the input capacitors, especially the highfrequency ceramic decoupling capacitors, close to the power
MOSFETs. Locate the output inductor and output capacitors
between the MOSFETs and the load. Locate the PWM
controller close to the MOSFETs.
Insure the current paths from the input capacitors to the
MOSFETs, to the output inductors and output capacitors are
as short as possible with maximum allowable trace widths.
A multi-layer printed circuit board is recommended. Dedicate
one solid layer for a ground plane and make all critical
component ground connections with vias to this layer.
Dedicate another solid layer as a power plane and break this
plane into smaller islands of common voltage levels. The
IPM6220
power plane should support the input power and output power
nodes. Use copper filled polygons on the top and bottom
circuit layers for the phase nodes, but do not unnecessarily
oversize these particular islands. Since the phase nodes are
subjected to very high dV/dt voltages, the stray capacitor
formed between these islands and the surrounding circuitry
will tend to couple switching noise. Use the remaining printed
circuit layers for small signal wiring. The wiring traces from the
control IC to the MOSFET gate and source should be sized to
carry 2A peak currents.
This filter configuration may be helpful on both the 3.3V and
5V Main outputs.
RSNS = R19 + R9
ISEN1
R9
200
FROM PHASE
NODE
C12
100pF
FIGURE 10. NOISE FILTER FOR ISEN1 INPUT
6. The bypass capacitors for VBATT and the soft-start
capacitors, CSS1 and CSS2 should be located close to
their connecting pins on the control IC. Minimize any
leakage current paths from SDWN1 and SDWN2 nodes,
since the internal current source is only 5µA.
Small Components Signal Layout Considerations
4. The VSNS1 and VSNS2 inputs should be bypassed with
a 1.0µF capacitor close to their respective IC pins.
5. A ‘T’ filter consisting of a ‘split’ RSNS and a small, 100pF,
capacitor as shown in Figure 10, may be helpful in
reducing noise coupling into the ISEN input. For example,
if the calculated value of RSNS1 is 2.2kΩ, dividing it as
shown with a 100pF capacitor provides filtering without
changing the current limit set point. For any calculated
value of RSNS, keep the value of the R9 portion to
approximately 200Ω, and the remainder of the resistance
in the R19 position. The 200Ω resistor and 100pF
capacitor provide effective filtering for noise above 8MHz.
+5.6-22VIN
R19
2K
7. Refer to the Application Note AN9915 for a recommended
component placement and interconnections.
Figure 11 shows an application circuit of a power supply for a
notebook PC microprocessor system. The power supply
provides +5V ALWAYS, +3.3V ALWAYS, +5.0V, +3.3V, and
12V from +5.6-22VDC battery voltage. For detailed information
on the circuit, including a Bill of Materials and circuit board
description, see Application Note AN9915. Also see Intersil’s
web site (www.intersil.com) for the latest information.
C4
56µF
C3, 6, 10
3x1µF
D2
BAT54WT1
GND
VBATT
1
+3.3V ALWAYS
(50mA)
3.3V ALWAYS
+
+5V ALWAYS
(50mA)
+
5V ALWAYS
C1
100µF
Q2
HUF76112SK8
UGATE2
L1
R10, 11 ISEN2
C22
330µF
22
20
19
4
Q4
HUF76112SK8
LGATE2
PGND2
VSEN2
SDWN2
C16
0.022µF
PGOOD
L4
2.7µH
ISEN1 R9, 19
2.2K
LGATE1
PGND1
+5V
(5A)
L2
8.2µH
+
Q5
HUF76112SK8
L3
6.8µH
+
C21, 32
2x330µF
C36
22µF
5
18
9
VSEN1
16
7
GATE3
+12V
(120mA)
D3
Q5
HUF76112SK8
+
R14
C24, 33
2x47µF
97.6K
8
R13
24.9K
VSEN3
10
15
11
17
SDWN1
C17
0.022µF
12
14
13
SDWNALL
GND
FIGURE 11. APPLICATIONS CIRCUIT
13
C9
0.15µF
PHASE1
IPM6220
3
Q3
HUF76112SK8
UGATE1
2.2K
8.2µH
+
6
21
PHASE2
+3.3V
(5A)
23
D1
BAT54WT1
BOOT2
C7
0.15µF
BOOT1
24
2
C2
10µF
IPM6220
Shrink Small Outline Plastic Packages (SSOP)
M24.15
N
INDEX
AREA
H
0.25(0.010) M
24 LEAD THIN SHRINK NARROW BODY SMALL OUTLINE
PLASTIC PACKAGE
B M
E
1
2
INCHES
GAUGE
PLANE
-B3
L
0.25
0.010
SEATING PLANE
-A-
h x 45o
A
D
-C-
α
e
B
0.17(0.007) M
A2
A1
C
0.10(0.004)
C A M
B S
NOTES:
1. Symbols are defined in the “MO Series Symbol List” in Section 2.2
of Publication Number 95.
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
3. Dimension “D” does not include mold flash, protrusions or gate
burrs. Mold flash, protrusion and gate burrs shall not exceed
0.15mm (0.006 inch) per side.
4. Dimension “E” does not include interlead flash or protrusions. Interlead flash and protrusions shall not exceed 0.25mm (0.010 inch)
per side.
5. The chamfer on the body is optional. If it is not present, a visual index feature must be located within the crosshatched area.
6. “L” is the length of terminal for soldering to a substrate.
7. “N” is the number of terminal positions.
8. Terminal numbers are shown for reference only.
9. Dimension “B” does not include dambar protrusion. Allowable dambar protrusion shall be 0.10mm (0.004 inch) total in excess of “B”
dimension at maximum material condition.
10. Controlling dimension: INCHES. Converted millimeter dimensions
are not necessarily exact.
14
MILLIMETERS
SYMBOL
MIN
MAX
MIN
MAX
NOTES
A
0.053
0.069
1.35
1.75
-
A1
0.004
0.010
0.10
0.25
-
A2
-
0.061
-
1.54
-
B
0.008
0.012
0.20
0.30
9
C
0.007
0.010
0.18
0.25
-
D
0.337
0.344
8.55
8.74
3
E
0.150
0.157
3.81
3.98
4
e
0.025 BSC
0.635 BSC
-
H
0.228
0.244
5.80
6.19
-
h
0.0099
0.0196
0.26
0.49
5
L
0.016
0.050
0.41
1.27
6
N
α
24
0o
24
8o
0o
7
8o
Rev. 0 12/00