SIPEX SP6132CU

SP6132
Evaluation Board Manual
ƒ
Easy Evaluation for the
SP6132 12V Input, 0 to 10A
Output Synchronous Buck
Converter
ƒ
Precision 0.80V with ±1% High
Accuracy Reference.
ƒ
UVIN and Output Dead Short Circuit
Shutdown Protection Features.
ƒ
High Efficiency: 94%
ƒ
Feature Rich: UVIN, Programmable Softstart,
External VCC Supply and Output Dead Short
Circuit Shutdown Protection.
SP6132EB SCHEMATIC
Rev 09/15/03
SP6132 Evaluation Manual
Copyright 2003 Sipex Corporation
USING THE EVALUATION BOARD
1) Powering Up the SP6132 Circuit
Connect the SP6132 Evaluation Board with an external +12V power supply. Connect
with short leads and large diameter wire directly to the “VIN” and “GND” posts. Connect
a Load between the VOUT and GND posts, again using short leads with large diameter
wire to minimize inductance and voltage drops.
2) Measuring Output Load Characteristics
It’s best to GND reference scope and digital meters using the Star GND post in the
center of the board. VOUT ripple can best be seen touching probe tip to the pad for
COUT and scope GND collar touching Star GND post – avoid a GND lead on the scope
which will increase noise pickup.
3) Using the Evaluation Board with Different Output Voltages
While the SP6132 Evaluation Board has been tested and delivered with the output set
to 3.30V, by simply changing one resistor, R2, the SP6132 can be set to other output
voltages. The relationship in the following formula is based on a voltage divider from the
output to the feedback pin VFB, which is set to an internal reference voltage of 0.80V.
Standard 1% metal film resistors of surface mount size 0603 are recommended.
Vout = 0.80V ( R1 / R2 + 1 ) or R2 = R1 / [ ( Vout / 0.80V ) – 1 ]
Where R1 = 68.1KΩ and for Vout = 0.80V setting, simply remove R2 from the board.
Furthermore, one could select the value of R1 and R2 combination to meet the exact
output voltage setting by restricting R1 resistance range such that 50KΩ ≤ R1 ≤ 100KΩ
for overall system loop stability.
Note that since the SP6132CU Evaluation Board design was optimized for 12V down
conversion to 3.30V, changes of output voltage and/or input voltage will alter
performance from the data given in the Power Supply Data section. In addition, the
SP6132CU provides short circuit protection by sensing Vout at GND however for
a better and robust current limit a comparator circuit could be used as shown on
the SP6132EB Schematic.
POWER SUPPLY DATA
The SP6132 is designed with a very accurate 1.0% reference over line, load and
temperature. Figure 1 data shows a typical SP6132CU Evaluation Board Efficiency plot,
with efficiencies to 94% and output currents to 10A. SP6132CU Load Regulation shown
in Figure 2 shows only 0.3% change in output voltage from no load to 10A load. Figures
3 and 4 illustrate a 0A to 5.0A and 5.0A to 10A Load Step. Start-up Response in Figures
5, 6 and 7 show a controlled start-up with different output load behavior when power is
applied where the input current rises smoothly as the Softstart ramp increases. In
Figure 8 the SP6132CU is configured for hiccup mode in response to an output dead
short circuit condition and will Softstart until the over-load is removed. Figure 9 and 10
show output voltage ripple less than 60mV at no load to 10A load.
While data on individual power supply boards may vary, the capability of the SP6132 of
achieving high accuracy over a range of load conditions shown here is quite impressive
and desirable for accurate power supply design.
2
3 .4 4
80
3 .4 3
70
3 .4 2
60
3 .4 1
Vout (V)
3 .4 5
90
Efficiency (%)
100
50
40
30
Vin=12V
Vout=3.3V
20
3 .4 0
3 .3 9
3 .3 8
Vin=12V
Vout=3.3V
3 .3 7
10
3 .3 6
0
2
4
6
8
10
3 .3 5
12
0
2
4
6
8
10
12
L o a d C u rre n t (A )
L o a d C u r r e n t (A )
Figure 1. Efficiency vs Load
Figure 2. Load Regulation
Vin=12V
Vout=3.3V
Vin=12V
Vout=3.3V
Vout
Vout
Iout (5A/div)
Iout (5A/div)
Figure 3. Load Step Response: 0->5A
Figure 4. Load Step Response: 5->10A
Vout
Vout
Vin
Vin
SoftStart
SoftStart
Iout (5A/div)
Iout (5A/div)
Figure 5. Start-Up Response: No Load
Figure 6. Start-Up Response: 5A Load
Vout
SoftStart
Vin
SoftStart
Vout
Iout (5A/div)
Ichoke(10A/div)
Figure 7. Start-Up Response: 10A Load
Figure 8. Output Load Short Circuit
3
+5V BIAS SUPPLY APPLICATION SCHEMATIC
In this application example, the SP6132CU is power by an external +5V bias supply
which current consumption of 20mA Maximum. If this supply is not available than it
is recommend Sipex SPX5205 Low-Noise LDO Voltage Regulator which is included
on the 6132CU Evaluation Board.
GH & GL
GH & GL
Vout ripple = 60mV
Vout ripple = 30mV
Ichoke(5A/div)
Ichoke(5A/div)
Figure 9. Output Ripple: No Load
Figure 10. Output Ripple: 10A Load
4
The SP6132EB is design for ease of a quick modification to accommodate for
applications that required both different input/output load voltage and current levels.
The change such that modification requiring only simple few on board components
direct replacement as show on the following Table 1.
Table 1: SP6132EB Suggested Components
SP6132EB Suggested Components for Different Input Voltage and Output Current Applications
QT, QB
DS
L1
C1, C2
C3, C4
R4
R5
5V Input, 2A Output
Fairchild Semi
OUTEasy Magnet
TDK
TDK
Panasonic
FDS6162N3
SD75-6R8M
C3225X5R0J476M
C3225X5R0J476M
ERJ-3EKF3322V
20V, 21A, 4.5mOhm
6.8uH, 2.54Arms,46mOhm 47uF Ceramic X5R 6.3V 47uF Ceramic X5R 6.3V 332K Ohm, 1%
Layout Size SO-8
Layout Size 7.8 x 7.0 mm Layout Size 1210
Layout Size 1210
Layout Size 0603
C1 IN and C2 OUT
C3 IN and C4 OUT
Yageo America
9C06031A0R0JLHFT
0.0 Ohm, 1%
Layout Size 0603
5V Input, 0 to 15A Output
Fairchild Semi
OUTEasy Magnet
FDS6162N3
SC5018-2R7M
20V, 21A, 4.5mOhm
2.7uH, 15.0A, 4.10mOhm
Layout Size SO-8
Layout Size 12.6 x 12.6 mm
TDK
TDK
Panasonic
C3225X5R0J476M
C3225X5R0J476M
ERJ-3EKF3322V
47uF Ceramic X5R 6.3V 47uF Ceramic X5R 6.3V 332K Ohm, 1%
Layout Size 1210
Layout Size 1210
Layout Size 0603
Yageo America
9C06031A0R0JLHFT
0.0 Ohm, 1%
Layout Size 0603
12V Input, 2A Output
Fairchild Semi
FDS7088N3
30V, 21A, 5mOhm
Layout Size SO-8
IN Easy Magnet
SD75-6R8M
6.8uH, 2.54Arms,46mOhm
Layout Size 7.8 x 7.0 mm
TDK
C3225X5R1C226M
22uF Ceramic X5R 16V
Layout Size 1210
C1 IN and C2 OUT
TDK
Panasonic
C3225X5R0J476M
ERJ-3EKF1003V
47uF Ceramic X5R 6.3V 100K Ohm, 1%
Layout Size 1210
Layout Size 0603
C3 IN and C4 OUT
TDK
MMZ1608R601A
High Freq Bead Filter
Layout Size 0603
12V Input, 0 to 15A Output
Fairchild Semi
FDS7088N3
30V, 21A, 5mOhm
Layout Size SO-8
IN Easy Magnet
SC5018-2R7M
2.7uH, 15.0A, 4.10mOhm
Layout Size 12.6 x 12.6 mm
TDK
C3225X5R1C226M
22uF Ceramic X5R 16V
Layout Size 1210
TDK
Panasonic
C3225X5R0J476M
ERJ-3EKF1003V
47uF Ceramic X5R 6.3V 100K Ohm, 1%
Layout Size 1210
Layout Size 0603
TDK
MMZ1608R601A
High Freq Bead Filter
Layout Size 0603
NOTES:
Referring to +5V Bias Supply Application Schematic, DS (STPS2L25U) OUT meaning
the application is not required to installed and vice versa. The same argument is also
applying both to C2, C4 OUT and C2, C4 IN.
5
LOOP COMPENSATION DESIGN
The open loop gain of the SP6132EB can be divided into the gain of the error
amplifier Gamp(s), PWM modulator Gpwm, buck converter output stage Gout(s), and
feedback resistor divider Gfbk. In order to crossover at the selecting frequency fco, the
gain of the error amplifier has to compensate for the attenuation caused by the rest of
the loop at this frequency. The goal of loop compensation is to manipulate the open
loop frequency response such that its gain crosses over 0dB at a slope of –20dB/dec.
The open loop crossover frequency should be higher than the ESR zero of the output
capacitors but less than 1/5 of the switching frequency fs to insure proper operation.
Since the SP6132EB is designed with a Ceramic Type output capacitors, a Type III
compensation circuit is required to give a phase boost of 180° in order to counteract the
effects of the output LC under damped resonance double pole frequency.
Figure 11. SP6132EB Voltage Mode Control Loop with Loop Dynamic
The simple guidelines for positioning the poles and zeros and for calculating the
component values for a Type III compensation are as follows.
a.
Choose fco = fs / 5
b.
Calculate fp_LC
fp_LC = 1 / 2π [(L) (C)] ^ 1/2
c.
Calculate fz_ESR
fz_ESR = 1 / 2π (Resr) (Cout)
d.
Select R1 component value such that 50kΩ ≤ R1 ≤ 100kΩ
e.
Calculate R2 base on the desired Vout
R2 = R1 / [(Vout / 0.80V) – 1]
6
f.
Select the ratio of Rz2 / R1 gain for the desired gain bandwidth
Rz2 = (R1) (Vramp_pp / Vin) (fco / fp_LC)
g.
Calculate Cz2 by placing the zero at ½ of the output filter pole frequency
Cz2 = 1 / π (Rz2) (fp_LC)
h.
Calculate Cp1 by placing the first pole at ESR zero frequency
Cp1 = 1 / 2π (Rz2) (fz_ESR)
i.
Calculate Rz3 by setting the second pole at ½ of the switching frequency and the
second zero at the output filter double pole frequency
Rz3 = 2 (R1) (fp_LC) / fs
j.
Calculate Cz3 from Rz3 component value above
Cz3 = 1 / π (Rz3) (fs)
k.
Choose 100pF ≤ Cf1 ≤ 220pF to stabilize the SP6132CU internal Error Amplify
As a particular example, consider for the following SP6132EB with a type III Voltage
Loop Compensation component selections:
Vin = 5 to 12V
Vout = 3.30V @ 0 to 10A load
Select L = 2.7uH => yield ≈ 20% of maximum 10A output current ripple.
Select Cout = 2x47uF Ceramic capacitors (Resr ≈ 2mΩ)
fs = 300khz SP6132CU internal Oscillator Frequency
Vramp_pp = 1.0V SP6132CU internal Ramp Peak to Peak Amplitude
Step by step design procedures:
a.
fco = 300khz / 5 = 60khz
b.
fp_LC = 1 / 2π [(2.7uH)(2)(47uF)]^1/2 ≅ 10khz
c.
fz_ESR = 1 / 2π (2mΩ)(2)(47uF) ≈ 850khz
d.
R1 = 68.1kΩ, 1%
e.
R2 = 68.1kΩ / [(3.30V / 0.80V) – 1] ≅ 21.5kΩ, 1%
f.
Rz2 = 68.1kΩ (1.0V / 12V) (60khz / 10khz) ≈ 40.2kΩ, 1%
g.
Cz2 = 1 / π (40.2kΩ) (10khz) ≈ 820pF, COG
h.
Cp1 = 1 / 2π (40.2kΩ) (850khz) ≈ 5pF => Select Cp1 = 56pF for noise filtering
i.
Rz3 = 2 (68.1kΩ) (10khz) / 300khz ≈ 4.64kΩ, 1%
j.
Cz3 = 1 / π (4.64kΩ) (300khz) ≅ 220pF, COG
k.
Cf1 = 100pF to stabilize SP6132CU internal Error Amplify
7
PC LAYOUT DRAWINGS
Figure 11. SP6132EB Component Placement
Figure 12. SP6132EB PC Layout Top Side
Figure 13. SP6132EB PC Layout Bottom Side
8
Table 2: SP6132EB List of Materials
SP6132 Evaluation Board List of Materials
Line
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
Ref.
Des.
PCB
U1
U2
U3
QT, QB
DS
DBST
L1
C3, C4
C1, C2
CVCC
C6, C8
C5, CBST
C7
CSS
CP1
CZ2
CF1
CZ3
R5
RZ2
R2
RZ3
R1
R3
R4, R6
R7, R8
R9, R10
RFL
J1
(J1)
VIN, VOUT, VCC, GND, GND2, GND3
UVIN, SS
Qty.
1
1
1
1
2
1
1
1
2
2
1
2
2
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
1
1
1
6
2
Manuf.
Manuf.
Part Number
Sipex
146-6521-01
Sipex
SP6132EB
Sipex
SP5205M5-5.0
National Semi
LM397MF
Fairchild Semi
FDS6676S
STMicroelectronics
STPS2L25U
ON-Semi
MBR0530
Easy Magnet
SC5018-2R7M
TDK
C3225X5R0J476M
TDK
C3225X5R1C226M
TDK
C2012X5R0J106M
TDK
C1608X5R1C103K
TDK
C1608X5R1A105K
TDK
C1608X7R1H104K
TDK
C1608X7R1H473K
TDK
C1608COG1H560J
TDK
C1608COG1H821J
TDK
C1608COG1H101J
TDK
C1608COG1H221J
TDK
MMZ1608R601A
Panasonic
ERJ-3EKF4022V
Panasonic
ERJ-3EKF2152V
Panasonic
ERJ-3EKF4641V
Panasonic
ERJ-3EKF6812V
Panasonic
ERJ-3EKF2212V
Panasonic
ERJ-3EKF1003V
Panasonic
ERJ-3EKF1502V
Panasonic
ERJ-3EKF1004V
Yageo America
9C06031A3R0JLHFT
Sullins
PTC36SAAN
Sullins
STC02SYAN
Vector Electronic
K24C/M
Mill-Max
3137-3002-10-0080
Layout
Size
1.75"X2.75"
MSOP-10
SOT-23-5
SOT-23-5
SO-8
SMB
SOD-123
12.6X12.6mm
1210
1210
0805
0603
0603
0603
0603
0603
0603
0603
0603
0603
0603
0603
0603
0603
0603
0603
0603
0603
0603
.32x.12
.2x.1
.042 Dia
.042 Dia
Component
SP6132 Eval PCB
2-15A Any-FET Buck Ctrl
150mA LDO Voltage Reg
Voltage Comparator
NFET
2A Schottky 10A RMS
0.5A Schottky
2.70uH Coil 12A 4.30mohm
47uF Ceramic X5R 6.3V
22uF Ceramic X5R 16V
10uF Ceramic X5R 6.3V
0.01uF Ceramic X5R 16V
1.0uF Ceramic X5R 10V
0.1uF Ceramic X7R 50V
47,000pF Ceramic X7R 50V
56pF Ceramic COG 50V
820pF Ceramic COG 50V
100pF Ceramic COG 50V
220pF Ceramic COG 50V
High Frequency Bead Filter
40.2K Ohm Thick Film Res 1%
21.5K Ohm Thick Film Res 1%
4.64K Ohm Thick Film Res 1%
68.1K Ohm Thick Film Res 1%
221K Ohm Thick Film Res 1%
100K Ohm Thick Film res 1%
15.0K Ohm Thick Film Res 1%
1.00M Ohm Thick Film Res 1%
3.0 Ohm Thick Film Res 5%
36-Pin (3x12) Header
Shunt
Test Point Post
Test Point Female Pin
ORDERING INFORMATION
Model
Temperature Range
Package Type
SP6132EB...............................0°C to +70°C...............……SP6132 Evaluation Board
SP6132CU..............................…. 0°C to +70°C.................................…….10-pin MSOP
9