SC2602STRT [SEMTECH]
Synchronous Voltage Mode Controller for Distributed Power Supply Applications; 同步电压模式控制器的分布式电源应用
| 型号： | SC2602STRT |
| 厂家： | 
SEMTECH CORPORATION |
| 描述： | Synchronous Voltage Mode Controller for Distributed Power Supply Applications |
| 文件： | 总16页 (文件大小：305K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SC2602/SC2602A
Synchronous Voltage Mode Controller
for Distributed Power Supply Applications
POWER MANAGEMENT
Features
Description
The SC2602 and SC2602A are low-cost, full featured,
synchronous voltage-mode controllers designed for use
in single ended power supply applications where efficiency
is of primary concern. Synchronous operation allows for
the elimination of heat sinks in many applications. The
SC2602s are ideal for implementing DC/DC converters
needed to power advanced microprocessors in low cost
systems, or in distributed power applications where effi-
ciency is important. Internal level-shift, high-side drive
circuitry, and preset shoot-thru control, allows the use of
inexpensive N-channel power switches.
Synchronous operation for high efficiency (95%)
RDS(ON) current sensing
On-chip power good and OVP functions
Small size with minimum external components
Soft Start
Enable function
Applications
Microprocessor core supply
Low cost synchronous applications
Voltage Regulator Modules (VRM)
DDR termination supplies
Networking power supplies
Sequenced power supplies
SC2602s features include temperature compensated
voltage reference, triangle wave oscillator and current
sense comparator circuitry. Power good signaling, shut-
down, and over voltage protection are also provided.
The SC2602 operates at a fixed 200kHz and the
SC2602A at 500kHz, providing a choice for optimum
compromise between efficiency, external component size,
and cost.
Two SC2602s can be used together to sequence power up
of telecom systems. The power good of the first SC2602
connected to the enable of the second SC2602 makes
this possible.
Typical Application Circuit
Typical Distributed Power Supply
+5V
+
R4
C6
680/6.3V
C5
C7
C8
Vin
R1
1k
R2
10
U1
C1
0.1
10.0
680/6.3V
680/6.3V
SC2602
C2
0.1
_ 5V
1
2
3
4
5
6
7
14
13
12
11
10
9
VCC
GND
SS/SHDN
COMP
SENSE
BSTH
PWRGD
OVP
C3
0.1
SHDN
PWRGD
OVP
820pF
R3
1k
4.99K
0.1
R8
124*
OCSET
PHASE
DRVH
PGND
R7
127
+12V
C4
1.0
D1
MBR0520
Q1
L1
STP40NE
2uH
BSTL
+
R5
3.9
Q2
STP40NE
8
DRVL
C9
C10
180/4V
C11
180/4V
C12
180/4V
C13
180/4V
180/4V Vout=2.5V
R6
2.2
*
_
NOTE:
Figure 1.
*) Vout = 1.265 x (1+R8/R7)
1
www.semtech.com
Revision: October 13, 2004
SC2602/SC2602A
POWER MANAGEMENT
Absolute Maximum Ratings
Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified
in the Electrical Characteristics section is not implied.
Parameter
Symbol
Maximum
Units
VCC, BSTL to GND
VIN
-1.0 to 16 (20V Surge)
V
V
PGND to GND
± 0.5
PHASE to GND(1)
-0.5 to 18 (20V Surge)
V
BSTH to PHASE
16 (20V Surge)
V
Thermal Resistance Junction to Case
Thermal Resistance Junction to Ambient
Operating Temperature Range
Maximum Junction Temperature
45
115
°C/W
°C/W
°C
θJC
θJA
TA
-40 to +85
125
TJ
°C
Storage Temperature Range
TSTG
TLEAD
ESD
-65 to +150
300
°C
Lead Temperature (Soldering) 10 Sec.
ESD Rating (Human Body Model)
°C
2
kV
Note: (1) -1.5V to 20V for 25ns repetitive every cycle.
Electrical Characteristics
Unless specified: VCC = 4.75V to 12.6V; GND = PGND = 0V; FB = VO; VBSTL = 12V; VBSTH-PHASE = 12V; TJ = 25oC
Parameter
Conditions
Min
Typ
Max
Units
Power Supply
Supply Voltage
Supply Current
Line Regulation
Error Amplifier
Gain (AOL)
VCC
4.2
12.6
10
V
mA
%
EN = VCC
VO = 2.5V
6
0.5
50
5
dB
µA
Input Bias
8
Oscillator
Oscillator Frequency
SC2602
180
450
90
200
500
95
220
550
kHz
%
SC2602A
Oscillator Max Duty Cycle
MOSFET Drivers
DH Source/Sink
BSTH - DH = 4.5V,
DH- PHASE = 2V
1
1
A
DL Source/Sink
BSTL - DL = 4.5V.
DL - PGND. = 2V
A
www.semtech.com
2004 Semtech Corp.
2
SC2602/SC2602A
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Unless specified: VCC = 4.75V to 12.6V; GND = PGND = 0V; FB = VO; VBSTL = 12V; VBSTH-PHASE = 12V; TJ = 25oC
Parameter
Conditions
Min
Typ
Max
Units
PROTECTION
OVP Threshold Voltage
OVP Source Current
Power Good Threshold
Dead Time
20
%
mA
%
V
OVP = 3V
10
88
112
100
220
45
ns
Over current Set Isink
Reference
2.0V ≤ VOCSET ≤ 12V
180
200
µA
Reference Voltage
Accuracy
0°C to 70°C
1.252
-1
1.265
1.278
+1
V
%
Soft Start
Charge Current
Discharge Current
V
SS = 1.5V
SS = 1.5V
8.0
10
12
µA
µA
V
1.5
Note:
(1) Specification refers to application circuit (Figure 1).
www.semtech.com
2004 Semtech Corp.
3
SC2602/SC2602A
POWER MANAGEMENT
Pin Configuration
Ordering Information
Device (1)(2)
SC2602STRT
SC2602ASTRT
SC2602EVB
Frequency
200kHz
Package
Top View
SO-14
VCC
PWRGD
OVP
GND
SS / SHDN
COMP
500kHz
Evaluation Board
OCSET
PHASE
DH
SENSE
BSTH
BSTL
DL
Notes:
(1) Only available in tape and reel packaging. A reel
contains 2500 devices.
(2) Lead free product.
PGND
(14-Pin SOIC)
Pin Descriptions
Pin #
Pin Name
Pin Function
1
VCC
PWRGD
OVP
Chip supply voltage.
2
Logic high indicates correct output voltage.
Over voltage protection.
3
4
OCSET
PHASE
DH
Sets the converter overcurrent trip point.
Input from the phase node between the MOSFETs.
High side driver output.
5
6
7
PGND
DL
Power ground.
8
Low side driver output.
9
BSTL
Bootstrap, low side driver.
Bootstrap, high side driver.
Voltage sense input.
10
BSTH
SENSE
COMP
SS/SHDN
GND
11
12
13
Compensation pin.
Soft start. A capacitor to ground sets the slow start time.
Signal ground.
14
Note:
(1) All logic level inputs and outputs are open collector TTL compatible.
www.semtech.com
2004 Semtech Corp.
4
SC2602/SC2602A
POWER MANAGEMENT
Block Diagram
Theory of Operation
Synchronous Buck Converter
Primary VCORE power is provided by a synchronous, volt- As SENSE increases, the output voltage of the error
age-mode pulse width modulated (PWM) controller. This amplifier decreases. This causes a reduction in the on-
section has all the features required to build a high effi- time of the high-side MOSFET connected to DH, hence
ciency synchronous buck converter, including “Power lowering the output voltage.
Good” flag, shut-down, and cycle-by-cycle current limit.
Under Voltage Lockout
The output voltage of the synchronous converter is set The under voltage lockout circuit of the SC2602 assures
and controlled by the output of the error amplifier. The that the high-side MOSFET driver outputs remain in the off
external resistive divider reference voltage is derived from state whenever the supply voltage drops below set param-
an internal trimmed-bandgap voltage reference (See Fig. eters. Lockout occurs if VCC falls below 4.1V. Normal opera-
1). The inverting input of the error amplifier receives its tion resumes once VCC rises above 4.2V.
voltage from the SENSE pin.
Over-Voltage Protection
The internal oscillator uses an on-chip capacitor and The over-voltage protection pin (OVP) is high only when
trimmed precision current sources to set the oscillation the voltage at SENSE is 20% higher than the target value
frequency to 200kHz/500kHz. The triangular output of programmed by the external resistor divider. The OVP pin
the oscillator sets the reference voltage at the inverting is internally connected to a PNP’s collector.
input of the comparator. The non-inverting input of the
comparator receives it’s input voltage from the error am- Power Good
plifier. When the oscillator output voltage drops below The power good function is to confirm that the regulator
the error amplifier output voltage, the comparator out- outputs are within +/-10% of the programmed level.
put goes high. This pulls DL low, turning off the low-side PWRGD remains high as long as this condition is met.
FET, and DH is pulled high, turning on the high-side FET PWRGD is connected to an internal open collector NPN
(once the cross-current control allows it). When the oscil- transistor.
lator voltage rises back above the error amplifier output
voltage, the comparator output goes low. This pulls DH
low, turning off the high-side FET, and DL is pulled high,
turning on the low-side FET (once the cross-current con-
trol allows it).
www.semtech.com
2004 Semtech Corp.
5
SC2602/SC2602A
POWER MANAGEMENT
Applications Information (Cont.)
Soft Start
Initially, SS/SHDN sources 10µA of current to charge an
external capacitor. The outputs of the error amplifiers
are clamped to a voltage proportional to the voltage on
SS/SHDN. This limits the on-time of the high-side
MOSFETs, thus leading to a controlled ramp-up of the
output voltages.
An over-current condition occurs when the high-side drive
is turned on, but the PHASE node does not reach the
voltage level set at the OCSET pin. The PHASE node is
sampled only once per cycle during the valley of the tri-
angular oscillator. Once an over-current occurs, the high-
side drive is turned off and the low-side drive turns on
and the SS/SHDN pin begins to sink 2µA. The soft-start
voltage will begin to decrease as the 2µA of current dis-
charges the external capacitor. When the soft-start volt-
age reaches 0.8V, the SS/SHDN pin will begin to source
10µA and begin to charge the external capacitor causing
the soft-start voltage to rise again. Again, when the soft-
start voltage reaches the level of the internal oscillator,
switching will occur.
RDS(ON) Current Limiting
The current limit threshold is set by connecting an exter-
nal resistor from the VCC supply to OCSET. The voltage
drop across this resistor is due to the 200µA internal
sink sets the voltage at the pin. This voltage is compared
to the voltage at the PHASE node. This comparison is
made only when the high-side drive is high to avoid false
current limit triggering due to uncontributing measure-
ments from the MOSFETs off-voltage. When the voltage
at PHASE is less than the voltage at OCSET, an overcurrent
condition occurs and the soft start cycle is initiated. The
synchronous switch turns off and SS/SHDN starts to
sink 2µA. When SS/SHDN reaches 0.8V, it then starts
to source 10µA and a new cycle begins.
If the over-current condition is no longer present, normal
operation will continue. If the over-current condition is
still present, the SS/SHDN pin will again begin to sink
2µA. This cycle will continue indefinitely until the over-
current condition is removed.
In conclusion, below is shown a typical “12V Application
Circuit” which has a BSTH voltage derived by bootstrapping
input voltage to the PHASE node through diode D1. This
circuit is very useful in cases where only input power of
12V is available.
Hiccup Mode
During power up, the SS/SHDN pin is internally pulled
low until VCC reaches the undervoltage lockout level of
4.2V. Once VCC has reached 4.2V, the SS/SHDN pin is
released and begins to source 10µA of current to the
external soft-start capacitor. As the soft-start voltage
rises, the output of the internal error amplifier is clamped
to this voltage. When the error signal reaches the level
of the internal triangular oscillator, which swings from 1V
to 2V at a fixed frequency of 200kHz/500kHz, switching
occurs. As the error signal crosses over the oscillator
signal, the duty cycle of the PWM signal continues to in-
crease until the output comes into regulation. If an over-
current condition has not occurred the soft-start voltage
will continue to rise and level off at about 2.2V.
In order to prevent substrate glitching, a small-signal di-
ode should be placed in close proximity to the chip with
cathode connected to PHASE and anode connected to
PGND.
www.semtech.com
2004 Semtech Corp.
6
SC2602/SC2602A
POWER MANAGEMENT
Application Circuit
Typical 12V Application Circuit with Bootstrapped BSTH
+5V
+
R4
10
C5
C6
C7
270/16V
C8
270/16V
R1
1k
R2
U1
Vin
_12V
270/16V
C1
0.1
10.0
1.74k
C2
0.1
SC2602
D2
MBRA130
1
2
3
14
13
12
VCC
GND
SS/SHDN
COMP
PWRGD
OVP
C3
0.1
SHDN
PWRGD
OVP
R3
1k
820pF
4.99K
R9
205*
4
5
6
11
10
9
OCSET
PHASE
DRVH
SENSE
BSTH
BSTL
R8
127
D1
MBR0520
C9
1.0
L1
4uH
Q1
C4
1.0
STP40NE
R5
3.9
+
Q2
STP40NE
7
8
D3
PGND
DRVL
C10
C11
180/4V
C12
180/4V
C13
180/4V
C14
MBRD1035
180/4V
180/4V
Vout=3.3
R6
2.2
Optional
V*
_
NOTE:
*) Vout = 1.265 x
(1+R9/R8)
www.semtech.com
2004 Semtech Corp.
7
SC2602/SC2602A
POWER MANAGEMENT
Typical Characteristics
Wave forms are shown for SC2602 and are similiar for
SC2602A but at higher frequency.
Output Ripple Voltage
Ch1: Vo_rpl
Gate Drive Waveforms
Ch1: Top FET
Ch2: Bottom FET
1. VIN = 5V; VO = 3.3V; IOUT = 12A
PIN Descriptions
Ch1: Vo_rpl
Ch1: Top FET
2. VIN = 5V; VOUT = 1.3V; IOUT = 12A
Ch2: Bottom FET
www.semtech.com
2004 Semtech Corp.
8
SC2602/SC2602A
POWER MANAGEMENT
Typical Characteristics (Cont.)
Ch1: Vo_rpl
Ch1: Top FET
2. VIN = 5V; VOUT = 1.3V; IOUT = 12A
Ch2: Bottom FET
www.semtech.com
2004 Semtech Corp.
9
SC2602/SC2602A
POWER MANAGEMENT
Typical Characteristics (Cont.)
Hiccup Mode
Ch1: Vin
Ch2: Vss
Ch3: Top Gate
Ch4: Vout
Vin = 5V
Vout = 3.3V
Vbst = 12V
Iout = S.C.
Start Up Mode
Ch1: Vin
Ch2: Vss
Ch3: Top Gate
Ch4: Vout
Vin = 5V
Vout = 3.3V
Iout = 2A
Vbst = 12V
www.semtech.com
2004 Semtech Corp.
10
SC2602/SC2602A
POWER MANAGEMENT
Typical Characteristics (Cont.)
Math Cad Close Loop Stability Analysis
Output Filter Schematic:
www.semtech.com
2004 Semtech Corp.
11
SC2602/SC2602A
POWER MANAGEMENT
Typical Characteristics (Cont.)
Error Amplifier Schematic
www.semtech.com
2004 Semtech Corp.
12
SC2602/SC2602A
POWER MANAGEMENT
Typical Characteristics (Cont.)
www.semtech.com
2004 Semtech Corp.
13
SC2602/SC2602A
POWER MANAGEMENT
Typical Characteristics (Cont.)
www.semtech.com
2004 Semtech Corp.
14
SC2602/SC2602A
POWER MANAGEMENT
Evaluation Board Schematic
www.semtech.com
2004 Semtech Corp.
15
SC2602/SC2602A
POWER MANAGEMENT
Outline Drawing - S0-14
DIMENSIONS
INCHES MILLIMETERS
A
DIM
A
MIN NOM MAX MIN NOM MAX
D
E
e
-
-
-
-
-
-
-
-
-
-
.053
.069 1.35
.010 0.10
.065 1.25
.020 0.31
.010 0.17
1.75
0.25
1.65
0.51
0.25
N
1
A1 .004
A2 .049
2X
E/2
b
c
D
.012
.007
.337 .341 .344 8.55 8.65 8.75
E1
E1 .150 .154 .157 3.80 3.90 4.00
E
e
.236 BSC
6.00 BSC
1.27 BSC
.050 BSC
-
-
h
L
.010
.020 0.25
0.50
2
3
ccc C
.016 .028 .041 0.40 0.72 1.04
B
(.041)
(1.04)
L1
N
2X N/2 TIPS
14
14
-
-
01
aaa
0°
8°
0°
8°
.004
.010
.008
0.10
0.25
0.20
bbb
ccc
D
aaa C
h
A2 A
SEATING
PLANE
h
C
A1
A-B D
H
bxN
bbb
C
c
GAGE
PLANE
0.25
L
(L1)
01
SEE DETAIL A
DETAIL A
SIDE VIEW
NOTES:
1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
2. DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE -H-
3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS
OR GATE BURRS.
4. REFERENCE JEDEC STD MS-012, VARIATION AB.
Land Pattern - S0-14
X
DIMENSIONS
DIM
INCHES
(.205)
.118
MILLIMETERS
(5.20)
3.00
1.27
0.60
2.20
7.40
C
G
P
X
Y
Z
(C)
G
Y
Z
.050
.024
.087
.291
P
NOTES:
1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.
CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR
COMPANY'S MANUFACTURING GUIDELINES ARE MET.
2. REFERENCE IPC-SM-782A, RLP NO. 302A.
Contact Information
Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805)498-2111 FAX (805)498-3804
www.semtech.com
2004 Semtech Corp.
16
相关型号：
SI9130DB
5- and 3.3-V Step-Down Synchronous ConvertersWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9135LG-T1
SMBus Multi-Output Power-Supply ControllerWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9135LG-T1-E3
SMBus Multi-Output Power-Supply ControllerWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9135_11
SMBus Multi-Output Power-Supply ControllerWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9136_11
Multi-Output Power-Supply ControllerWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9130CG-T1-E3
Pin-Programmable Dual Controller - Portable PCsWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9130LG-T1-E3
Pin-Programmable Dual Controller - Portable PCsWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9130_11
Pin-Programmable Dual Controller - Portable PCsWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9137
Multi-Output, Sequence Selectable Power-Supply Controller for Mobile ApplicationsWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9137DB
Multi-Output, Sequence Selectable Power-Supply Controller for Mobile ApplicationsWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9137LG
Multi-Output, Sequence Selectable Power-Supply Controller for Mobile ApplicationsWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9122E
500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification DriversWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
©2020 ICPDF网 联系我们和版权申明