NJW4132
Switching Regulator IC for Boost Converter
Current Mode Control w/ 45V/1.75A MOSFET
GENERAL DESCRIPTION
■ PACKAGE OUTLINE
The NJW4132 is a boost converter with 45V/1.75A MOSFET. It
corresponds to high oscillating frequency, and Low ESR Output
Capacitor (MLCC) within wide input range from 4.5V to 40V.
Therefore, the NJW4132 can realize downsizing of applications
with a few external parts so that adopts current mode control.
Also, it has a soft start function, external clock synchronization,
over current protection and thermal shutdown circuit.
It is suitable for boost application to a Car Accessory, Office
Automation Equipment, Industrial Instrument and so on.
NJW4132U2
FEATURES
Current Mode Control
External Clock Synchronization
Wide Operating Voltage Range
4.5V to 40V
Switching Current
1.75A min.
PWM Control
Built-in Compensation Circuit
Correspond to Ceramic Capacitor (MLCC)
Oscillating Frequency
300kHz typ. (A ver.)
700kHz typ. (B ver.)
2.0MHz typ. (C ver.)
Soft Start Function
10ms typ.
UVLO (Under Voltage Lockout)
Over Current Protection (Hiccup type)
Thermal Shutdown Protection
Standby Function
Package Outline
NJW4132U2
: SOT-89-5-2
PRODUCT CLASSIFICATION
Version
Oscillation
Frequency
Package
NJW4132U2-A
A
300kHz typ.
SOT-89-5-2
NJW4132U2-B
B
700kHz typ.
SOT-89-5-2
NJW4132U2-C
C
2.0MHz typ.
SOT-89-5-2
Part Number
Ver.2017-01-25
Operating
Temperature
Range
General Spec.
-40 C to +85 C
General Spec.
-40 C to +85 C
General Spec.
-40 C to +85 C
-1-
NJW4132
PIN CONFIGURATION
5
(2)
4
PIN FUNCTION
1. SW
2. GND
3. IN4. EN/SYNC
5. V+
1
2
3
NJW4132U2
BLOCK DIAGRAM
V+
SW
UVLO
TSD
EN/SYNC
Enable
(Standby)
High: ON
Low : OFF(Standby)
100k
SYNC
S Q
OSC
Buffer
R
Low Frequency
Control
PWM
INER AMP
Soft Start
Vref
OCP
CURRENT
SENSE
1V
SLOPE
COMP.
GND
-2-
Ver.2017-01-25
NJW4132
ABSOLUTE MAXIMUM RATINGS
PARAMETER
SYMBOL
Supply Voltage
V+
SW pin Voltage
VSW
IN- pin Voltage
VINEN/SYNC pin Voltage
VEN/SYNC
Power Dissipation
PD
Junction Temperature Range
Operating Temperature Range
Storage Temperature Range
Tj
Topr
Tstg
MAXIMUM RATINGS
+45
+45
-0.3 to +6
+45
SOT-89-5-2
625 (*1)
2,400 (*2)
-40 to +150
-40 to +85
-40 to +150
(Ta=25°C)
UNIT
V
V
V
V
mW
C
C
C
(*1): Mounted on glass epoxy board. (76.2×114.3×1.6mm:based on EIA/JEDEC standard, 2Layers)
(*2): Mounted on glass epoxy board. (76.2×114.3×1.6mm:based on EIA/JEDEC standard, 4Layers)
(For 4Layers: Applying 74.2×74.2mm inner Cu area and a thermal via hole to a board based on JEDEC standard JESD51-5)
RECOMMENDED OPERATING CONDITIONS
PARAMETER
SYMBOL
Supply Voltage
V+
External Clock Input Range
A version
fSYNC
B version
C version
Ver.2017-01-25
MIN.
4.5
TYP.
–
MAX.
40
290
690
1,800
–
–
–
500
1,000
2,400
UNIT
V
kHz
-3-
NJW4132
(Unless otherwise noted, V+=VEN./SYNC=12V, Ta=25 C)
ELECTRICAL CHARACTERISTICS
PARAMETER
SYMBOL
Under Voltage Lockout Block
ON Threshold Voltage
OFF Threshold Voltage
Hysteresis Voltage
VT_ON
VT_OFF
VHYS
TSS
Soft Start Block
Soft Start Time
TEST CONDITION
MIN.
TYP.
MAX.
UNIT
V+= L → H
V+= H → L
4.2
4.1
70
4.35
4.25
100
4.5
4.4
–
V
V
mV
VB=0.95V
5
10
15
ms
270
630
1.82
–
–
–
300
700
2.0
50
117
410
330
770
2.2
–
–
–
kHz
kHz
MHz
kHz
kHz
kHz
Oscillator Block
Oscillation Frequency
fOSC
Oscillation Frequency
OCP operates
fOSC_LIM
Oscillation Frequency
deviation (Supply voltage)
Oscillation Frequency
deviation (Temperature)
Error Amplifier Block
Reference Voltage
Input Bias Current
A version, VIN-=0.9V
B version, VIN-=0.9V
C version, VIN-=0.9V
A version, VIN-=0.4V
B version, VIN-=0.4V
C version, VIN-=0.4V
fDV
V+=4.5V to 40V
–
1
–
%
fDT
Ta=-40 C to +85 C
–
5
–
%
-1.0%
-0.1
1.0
–
+1.0%
0.1
V
A
85
80
–
–
–
–
–
–
90
85
300
110
80
220
90
80
–
–
425
155
120
355
125
120
%
%
ns
ns
ns
ns
ns
ns
–
42
–
ms
–
1.75
–
0.4
2.1
–
0.65
2.25
1
A
A
VB
IB
PWM Comparate Block
Maximum Duty Cycle
MAXDUTY
Minimum ON Time1
(Use Built-in Oscillator)
tON-min1
Minimum ON Time2
(Use Ext CLK)
tON-min2
OCP Block
COOL DOWN Time
tCOOL
Output Block
Output ON Resistance
Switching Current Limit
SW Leak Current
RON
ILIM
ILEAK
-4-
A version, B version, VIN-=0.9V
C version, VIN-=0.9V
A version
B version
C version
A version, fSYNC=400kHz
B version, fSYNC=800kHz
C version, fSYNC=2.2MHz
ISW=1A
VEN/SYNC=0V, VSW=45V
Ver.2017-01-25
NJW4132
ELECTRICAL CHARACTERISTICS
PARAMETER
Standby Control Block
ON Control Voltage
OFF Control Voltage
Input Bias Current
(EN/SYNC pin)
SYMBOL
VON
VOFF
IEN
(Unless otherwise noted, V+=VEN/SYNC=12V, Ta=25 C)
TEST CONDITION
VEN/SYNC= L → H
VEN/SYNC= H → L
A version, B version,
VEN/SYNC=12V
C version, VEN/SYNC=12V
MIN.
TYP.
MAX.
UNIT
1.6
0
–
–
V+
0.5
V
V
–
165
300
A
–
250
400
A
–
2.1
2.65
mA
–
2.5
3.0
mA
–
3.5
4.0
mA
–
–
1
A
General Characteristics
Quiescent Current
Standby Current
Ver.2017-01-25
IDD
IDD_STB
A version,
RL=no load, VIN-=0.9V
B version,
RL=no load, VIN-=0.9V
C version,
RL=no load, VIN-=0.9V
VEN/SYNC=0V
-5-
NJW4132
TYPICAL APPLICATIONS
Boost Converter
V IN
L
CIN
SBD
COUT
V OUT
CFB
R2
RFB
V+
SW
NJW4132
EN/
SYNC
GND
R1
IN-
EN/SYNC
High: ON
Low: OFF
(Standby)
Buck-Boost (SEPIC) Converter
V IN
L1
CIN
C1
SBD
COUT
V OUT
CFB
R2
RFB
V+
SW
NJW4132
EN/
SYNC
GND
L2
R1
IN-
EN/SYNC
High: ON
Low: OFF
(Standby)
-6-
Ver.2017-01-25
NJW4132
TYPICAL CHARACTERISTICS (A, B, C version)
Reference Voltage vs. Supply Voltage
(Ta=25°C)
Reference Voltage VB (V)
1.01
1.005
1
0.995
0.99
Switching Current Limit I LIM (A)
1
0.995
0.99
0
2.8
1.005
10
20
30
Supply Voltage V+ (V)
40
-50
Switching Current Limit vs. Temperature
2.6
2.4
+
V =4.5V, 12V, 40V
2.2
2
1.8
1.6
1.4
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
Output ON Resistance vs. Temperature
(ISW=1A)
0.8
Output ON Resistance RON (W)
Reference Voltage VB (V)
1.01
Reference Voltage vs. Temperature
(V+=12V)
0.7
0.6
V+=4.5V, 12V, 40V
0.5
0.4
0.3
0.2
0.1
0
-50
Ver.2017-01-25
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
-50
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
-7-
NJW4132
TYPICAL CHARACTERISTICS (A, B, C version)
Under Voltage Lockout Voltage vs. Temperature
4.5
15
14
VT_ON
4.4
4.35
4.3
VT_OFF
4.25
4.2
Soft Start Time Tss (ms)
Threshold Voltage (V)
4.45
13
12
11
10
9
8
7
4.15
6
4.1
5
-50
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
2.5
2
1.5
1
0.5
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
Standby Current vs. Temperature
(VEN/SYNC=0V)
1
Standby Current IDD_STB (μA)
Switching Leak Current I LEAK (μA)
-50
Switching Leak Current vs. Temperature
(V+=12V, VEN/SYNC=0V, VSW=45V)
3
0.9
0.8
0.7
0.6
0.5
V+=40V
V+=12V
V+=4.5V
0.4
0.3
0.2
0.1
0
0
-50
-8-
Soft Start Time vs. Temperature
(V+=12V, VB=0.95V)
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
-50
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
Ver.2017-01-25
NJW4132
TYPICAL CHARACTERISTICS (A version)
Oscillation Frequency vs. Supply Voltage
(A ver., VIN-=0.9V, Ta=25°C)
3
315
Quiescent Current IDD (mA)
Oscillation Frequnecny fOSC (kHz)
320
310
305
300
295
290
285
280
10
20
30
Supply Voltage V+ (V)
2
1.5
1
0.5
40
0
Oscillation Frequency vs Temperature
(A ver., V+=12V, VIN-=0.9V)
320
310
300
290
280
270
10
20
30
Supply Voltage V+ (V)
40
Maximum Duty Cycle vs. Temperature
(A ver., V+=12V, VIN-=0.9V)
100
Maximum Duty Cycle MAXDUTY (%)
330
Oscillation Frequency fosc (kHz)
2.5
0
0
98
96
94
92
90
88
86
84
-50
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
-50
Minimum ON Time1 vs. Temperature
(A ver., V+=12V)
400
350
300
250
200
150
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
Quiescent Current vs. Temperature
(A ver., RL=no load, VIN-=0.9V)
3
Quiescent Current IDD (mA)
450
Minimum ON Time1 tON-min1 (ns)
Quiescent Current vs. Supply Voltage
(A ver., RL=no load, VIN-=0.9V, Ta=25°C)
2.5
V+=12V, 40V
2
V+=4.5V
1.5
1
0.5
0
-50
Ver.2017-01-25
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
-50
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
-9-
NJW4132
TYPICAL CHARACTERISTICS (B version)
Oscillation Frequency vs. Supply Voltage
(B ver., VIN-=0.9V, Ta=25°C)
3
715
Quiescent Current IDD (mA)
Oscillation Frequnecny fOSC (kHz)
720
710
705
700
695
690
685
680
2
1.5
1
0.5
40
0
760
740
720
700
680
660
640
620
10
20
30
Supply Voltage V+ (V)
40
Maximum Duty Cycle vs. Temperature
(B ver., V+=12V, VIN-=0.9V)
100
Maximum Duty Cycle MAXDUTY (%)
Oscillation Frequency fosc (kHz)
10
20
30
Supply Voltage V+ (V)
Oscillation Frequency vs Temperature
(B ver., V+=12V, VIN-=0.9V)
780
98
96
94
92
90
88
86
84
-50
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
-50
Minimum ON Time1 vs. Temperature
(B ver., V+=12V)
180
160
140
120
100
80
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
Quiescent Current vs. Temperature
(B ver., RL=no load, VIN-=0.9V)
3
Quiescent Current IDD (mA)
Minimum ON Time1 tON-min1 (ns)
2.5
0
0
2.5
V+=4.5V, 12V, 40V
2
1.5
1
0.5
0
60
-50
- 10 -
Quiescent Current vs. Supply Voltage
(B ver., RL=no load, VIN-=0.9V, Ta=25°C)
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (°C)
-50
-25
0
25
50
75
100 125 150
Ambient Temperature Ta (°C)
Ver.2017-01-25
NJW4132
TYPICAL CHARACTERISTICS (C version)
Oscillation Frequency vs. Supply Voltage
(C ver., VIN-=0.9V, Ta=25ºC)
4
2.08
3.5
Quiescent Current IDD (mA)
Oscillation Frequency fOSC (MHz)
2.1
2.06
2.04
2.02
2
1.98
1.96
1.94
3
2.5
2
1.5
1
0.5
1.92
1.9
0
0
40
0
2.1
2
1.9
1.8
1.7
10
20
30
Supply Voltage V+ (V)
40
Maximum Duty Cycle vs. Temperature
(C ver., V+=12V, VIN-=0.9V)
100
Maximum Duty Cycle MAXDUTY (%)
Oscillation Frequency fOSC (MHz)
10
20
30
Supply Voltage V+ (V)
Oscillation Frequency vs. Temperature
(C ver., V+=12V, VIN-=0.9V)
2.2
98
96
94
92
90
88
86
84
82
80
-50
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (ºC)
-50
Minimum ON Time1 vs. Temperature
(C ver., V+=12V)
100
80
60
40
20
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (ºC)
Quiescent Current vs. Temperature
(C ver., RL=no load, VIN-=0.9V)
4
Quiescent Current IDD (mA)
120
Minimum ON Time1 tON-min1 (ns)
Quiescent Current vs. Supply Voltage
(C ver., RL=no load, VIN-=0.9V, Ta=25ºC)
3.5
V+=4.5V, 12V, 40V
3
2.5
2
1.5
1
0.5
0
0
-50
Ver.2017-01-25
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (ºC)
-50
-25
0
25 50 75 100 125 150
Ambient Temperature Ta (ºC)
- 11 -
NJW4132
NJW4132Application Manual
Technical Information
PIN DESCRIPTIONS
SW
GND
PIN
NUMBER
1
2
IN-
3
EN/SYNC
4
V+
5
PIN NAME
- 12 -
FUNCTION
Switch Output pin of Power MOSFET
GND pin
Output Voltage Detecting pin
Connects output voltage through the resistor divider tap to this pin in order to voltage
of the IN- pin become 1.0V.
Standby Control pin
The EN/SYNC pin internally pulls down with 100k . Normal Operation at the time of
High Level. Standby Mode at the time of Low Level or OPEN.
Moreover, it operates by inputting clock signal at the oscillatory frequency that
synchronized with the input signal.
Power Supply pin for Power Line
Ver.2017-01-25
NJW4132 ApplicationNJW4132
Manual
Technical Information
Description of Block Features
1. Basic Functions / Features
Error Amplifier Section (ER AMP)
1.0V±1% precise reference voltage is connected to the non-inverted input of this section.
To set the output voltage, connects converter's output to inverted input of this section (IN- pin). If requires output
voltage, inserts resistor divider.
Because the optimized compensation circuit is built-in, the application circuit can be composed of minimum
external parts.
PWM Comparator Section (PWM), Oscillation Circuit Section (OSC)
The NJW4132 uses a constant frequency, current mode step up architecture. The oscillation frequency are
300kHz (typ.) at A version, 700kHz (typ.) at B version and 2.0MHz (typ.) at C version. The PWM signal is output by
feedback of output voltage and slope compensation switching current at the PWM comparator block.
The maximum duty ratio is 90% (typ.) in A version and B version.
Minimum ON time is limited in the inside of the IC. (Table 1.)
Table 1. Minimum ON time of NJW4132
A version
(fOSC =300kHz)
Use Built-in
300ns typ.
Oscillator
Use External
220ns typ.
Clock
(@ fSYNC=400kHz)
B version
(fOSC =700kHz)
C version
(fOSC =2.0MHz)
110ns typ.
80ns typ.
90ns typ.
(@ fSYNC=800kHz)
80ns typ.
(@ fSYNC=2.2MHz)
The boost converter of ON time is decided the following formula.
ton
1
VIN
VOUT
1
f OSC
s
VIN shows input voltage and VOUT shows output voltage.
When the ON time becomes below in tON-min, in order to maintain output voltage at a stable state, change of duty or
pulse skip operation may be performed.
Power MOSFET (SW Output Section)
The power is stored in the inductor by the switch operation of built-in power MOSFET. The output current is limited
to 1.75A(min.) the overcurrent protection function.
Power Supply, GND pin (V+ and GND)
In line with switching element drive, current flows into the IC according to frequency. If the power supply
impedance provided to the power supply circuit is high, it will not be possible to take advantage of IC performance
due to input voltage fluctuation. Therefore connect the input capacitor near V+ pin – the GND pin. When an IC and
an input capacitor are far, insert bypass capacitor generally 0.1 F, and lower the high frequency impedance.
Ver.2017-01-25
- 13 -
NJW4132
NJW4132Application Manual
Technical Information
Description of Block Features (Continued)
2. Additional and Protection Functions / Features
Under Voltage Lockout (UVLO)
The UVLO circuit operating is released above V+=4.35V(typ.) and IC operation starts. When power supply voltage
is low, IC does not operate because the UVLO circuit operates. There is 100mV(typ.) width hysteresis voltage at rise
and decay of power supply voltage. Hysteresis prevents the malfunction at the time of UVLO operating and
releasing.
Soft Start Function (Soft Start)
The output voltage of the converter gradually rises to a set value by the soft start function. The soft start time is
10ms (typ.). It is defined with the time of the error amplifier reference voltage becoming from 0V to 0.95V. The soft
start circuit operates after the release UVLO and/or recovery from thermal shutdown.
1.0V
Vref,
IN- pin Voltage
OSC Waveform
ON
SW pin
OFF
UVLO(4.35V typ.) Release,
Standby,
Recover from Thermal
Shutdow n
Soft Start time: Tss=10ms(typ.) to V B=0.95V
Steady
Operaton
Soft Start effective period to V B=1.0V
Fig. 1. Startup Timing Chart
- 14 -
Ver.2017-01-25
NJW4132 ApplicationNJW4132
Manual
Technical Information
Description of Block Features (Continued)
Over Current Protection Circuit (OCP)
NJW4132 contains overcurrent protection circuit of hiccup architecture. The overcurrent protection circuit of hiccup
architecture is able to decrease heat generation at the overload.
The NJW4132 output returns automatically along with release from the over current condition.
At when the switching current becomes ILIM or more, the overcurrent protection circuit is stopped the MOSFET
output. The switching output holds low level down to next pulse output at OCP operating.
When IN- pin voltage becomes 0.75V or less, it oscillation frequency decreases to approximately 17%
At the same time starts pulse counting, and stops the switching operation when the overcurrent detection
continues approx 7ms (@ A ver.), 5ms (@ B ver.) and 2ms (@C ver.).
After NJW4132 switching operation was stopped, it restarts by soft start function after the cool down time of approx
42ms (typ.).
IN- pin
Voltage
1.0V
0.75V
0V
Oscillation Frequency
A ver.=300kHz typ.
B ver.=700kHz typ.
C ver.=2.0MHz typ.
OCP Operates Oscillation Frequency
A ver.=50kHz typ.
B ver.=117kHz typ.
C ver.=410kHz typ.
ON
SW pin
OFF
Switching
Current
ILIM
0
Pulse by
Pulse
Static Status
Pulse Count
A ver.=about 7ms
B ver.=about 5ms
C ver.=about 2ms
Cool Down time :42ms typ.
Detect
Overcurrent
Soft Start
Fig. 2. Timing Chart at Over Current Detection
Thermal Shutdown Function (TSD)
When Junction temperature of the NJW4132 exceeds the 160°C*, internal thermal shutdown circuit function stops
SW function. When junction temperature decreases to 145°C* or less, SW operation returns with soft start operation.
The purpose of this function is to prevent malfunctioning of IC at the high junction temperature. Therefore it is not
something that urges positive use. You should make sure to operate within the junction temperature range rated
(150 C). (* Design value)
Standby Function
The NJW4132 stops the operating and becomes standby status when the EN/SYNC pin becomes less than 0.5V.
The EN/SYNC pin internally pulls down with 100k , therefore the NJW4132 becomes standby mode when the
EN/SYNC pin is OPEN. You should connect this pin to V+ when you do not use standby function.
Ver.2017-01-25
- 15 -
NJW4132
NJW4132Application Manual
Technical Information
Description of Block Features (Continued)
External Clock Synchronization
By inputting a square wave to EN/SYNC pin, can be synchronized to an external frequency.
You should fulfill the following specification about a square wave. (Table 2.)
Table 2. The input square wave to an EN/SYNC pin.
A version
B version
(fOSC =300kHz)
(fOSC =700kHz)
290kHz to
690kHz to
Input Frequency
500kHz
1,000kHz
Duty Cycle
20% to 80%
35% to 65%
Voltage
1.6V or more at High level
magnitude
0.5V or less at Low level
C version
(fOSC =2.0MHz)
1.8MHz to
2.4MHz
40% to 60%
The trigger of the switching operating at the external synchronized mode is detected to the rising edge of the input
signal. At the time of switching operation from standby or asynchronous to synchronous operation, it has set a delay
time approx 20 s to 30 s (@ A ver.) , 10 s to 20 s (@ B ver.) and 3 s to 8 s (@ C ver.) in order to prevent
malfunctions. (Fig. 3.)
High
EN/SYNC pin
Low
ON
SW pin
OFF
Standby
Delay Time
External Clock Synchronization
Fig. 3. Switching Operation by External Synchronized Clock
- 16 -
Ver.2017-01-25
NJW4132 ApplicationNJW4132
Manual
Technical Information
Application Information
Inductors
Because a large current flows to the inductor, you should select the inductor with the large current capacity not to
saturate. Optimized inductor value is determined by the input voltage and output voltage.
The Optimized inductor value: (It is a reference value.)
VIN=5V VOUT=12V
: L < = 10 H
You should set the inductor as a guide from above mentioned value to half value.
Reducing L decreases the size of the inductor. However a peak current increases and adversely affects the
efficiency. (Fig. 4.)
Moreover, you should be aware that the output current is limited because it becomes easy to operating to the
overcurrent limit.
The peak current is decided the following formula.
IIN
IL
Ipk
VOUT IOUT
A
VIN
VOUT VIN VIN
[A]
L VOUT fOSC
IL
[A]
2
IIN
Current
Peak Current IPK
Inductor
Ripple Current DIL
Peak Current IPK
Input Current
IIN
Inductor
Ripple Current DIL
0
tON
tOFF
Reducing L Value
tON
tOFF
Increasing L value
Fig. 4. Inductor Current State Transition (Continuous Conduction Mode)
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NJW4132
NJW4132Application Manual
Technical Information
Application Information (Continued)
Catch Diode
When the switch element is in OFF cycle, power stored in the inductor flows via the catch diode to the output
capacitor. Therefore during each cycle current flows to the diode in response to load current. Because diode's
forward saturation voltage and current accumulation cause power loss, a Schottky Barrier Diode (SBD), which has a
low forward saturation voltage, is ideal.
An SBD also has a short reverse recovery time. If the reverse recovery time is long, through current flows when
the switching transistor transitions from OFF cycle to ON cycle. This current may lower efficiency and affect such
factors as noise generation.
When the switch element is in ON cycle, a reverse voltage flows to SBD. Therefore you should select a SBD that
has reverse voltage rating greater than maximum output voltage. The power loss, which stored in output capacitor,
will be increase due to increasing reverse current through SBD at high temperature. Therefore, there is cases
preferring reverse current characteristics to forward current characteristic in order to improve efficiency.
Input Capacitor
Transient current flows into the input section of a switching regulator responsive to frequency. If the power supply
impedance provided to the power supply circuit is large, it will not be possible to take advantage of the NJW4132
performance due to input voltage fluctuation. Therefore insert an input capacitor as close to the MOSFET as
possible.
Output Capacitor
An output capacitor stores power from the inductor, and stabilizes voltage provided to the output.
Because NJW4132 corresponds to the output capacitor of low ESR, the ceramic capacitor is the optimal for
compensation.
The Optimized capacitor value: (It is a reference value.)
VOUT =12V
: COUT > = 22 F
In addition, you should consider varied characteristics of capacitor (a frequency characteristic, a temperature
characteristic, a DC bias characteristic and so on) and unevenness peculiar to a capacitor supplier enough.
Therefore when selecting a capacitors, you should confirm the characteristics with supplier datasheets.
When selecting an output capacitor, you must consider Equivalent Series Resistance (ESR) characteristics, ripple
current, and breakdown voltage.
The output ripple noise can be expressed by the following formula.
Vripple(p
ESR
p)
IL [ V ]
The effective ripple current that flows in a capacitor (Irms) is obtained by the following equation.
Irms
- 18 -
IPK
2
2
IOUT [ Arms ]
Ver.2017-01-25
NJW4132 ApplicationNJW4132
Manual
Technical Information
Application Information (Continued)
Setting Output Voltage, Compensation Capacitor
The output voltage VOUT is determined by the relative resistances of R1, R2. The current that flows in R1, R2 must
be a value that can ignore the bias current that flows in ER AMP.
R2
R1
VOUT
1
VB [ V ]
The zero points are formed with R2 and CFB, and it makes for the phase compensation of NJW4132.
The zero point is shown the following formula.
f Z1
2
1
[Hz]
R2 C FB
You should set the zero point as a guide from 20kHz to 60kHz. Please optimize CFB by application.
Ver.2017-01-25
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NJW4132
NJW4132Application Manual
Technical Information
Application Information (Continued)
Board Layout
In the switching regulator application, because the current flow corresponds to the oscillation frequency, the
substrate (PCB) layout becomes an important.
You should attempt the transition voltage decrease by making a current loop area minimize as much as possible.
Therefore, you should make a current flowing line thick and short as much as possible. Fig.5. shows a current loop
at Boost converter.
L
V IN
SBD
CIN
NJW4132
Built-in SW
L
COUT
V IN
SBD
CIN
(a) Boost Converter SW ON
COUT
NJW4132
Built-in SW
(b) Boost Converter SW OFF
Fig. 5. Current Loop at Boost Converter
Concerning the GND line, it is preferred to separate the power system and the signal system, and use single
ground point.
The voltage sensing feedback line should be as far away as possible from the inductance. Because this line has
high impedance, it is laid out to avoid the influence noise caused by flux leaked from the inductance.
Fig. 6. shows example of wiring at boost converter. Fig. 7. shows the PCB layout example.
L
SBD
V OUT
SW
V IN
CIN
COUT
V+
RL
GND
The capacitor is
connected near an IC.
NJW4132
RFB
CFB
INR2
R1
Because IN- pin is high impedance, the
voltage detection resistance: R1/R2 is
put as much as possible near IC(IN-).
To avoid the influence of the voltage
drop, the output voltage should be
detected near the load.
Separate Digital(Signal)
GND from Pow er GND
Fig. 6. Board Layout at Boost Converter
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Ver.2017-01-25
NJW4132 ApplicationNJW4132
Manual
Technical Information
Application Information (Continued)
VOUT
VIN
SBD
L
1pin
C OUT
C IN
Signal
GND
Area
Feed back
signal
R1
RFB
C FB
R2
GND OUT
EN/SYNC
GND IN
Power GND Area
Connect Signal GND line and Power GND line on backside pattern
Fig. 7. Layout Example (upper view)
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NJW4132
NJW4132Application Manual
Technical Information
Calculation of Package Power
A lot of the power consumption of boost converter occurs from the internal switching element (Power MOSFET).
Power consumption of NJW4132 is roughly estimated as follows.
Input Power:
Output Power:
Diode Loss:
NJW4132 Power Consumption:
Where:
VIN
VOUT
VF
OFF duty
PIN = VIN IIN [W]
POUT = VOUT IOUT [W]
PDIODE = VF IL(avg) OFF duty [W]
PLOSS = PIN POUT PDIODE [W]
: Input Voltage for Converter
: Output Voltage of Converter
: Diode's Forward Saturation Voltage
: Switch OFF Duty Cycle
IIN
IOUT
IL(avg)
: Input Current for Converter
: Output Current of Converter
: Inductor Average Current
Efficiency ( ) is calculated as follows.
= (POUT PIN) 100 [%]
You should consider temperature derating to the calculated power consumption: PD.
You should design power consumption in rated range referring to the power dissipation vs. ambient temperature
characteristics (Fig. 8).
NJW4132U2 (SOT-89-5-2 Package)
Power Dissipation vs. Ambient Temperature
(Tj=~150°C)
Power Dissipation PD (mW)
3000
At on 4 layer PC Board (*4)
At on 2 layer PC Board (*3)
2500
2000
1500
1000
500
0
-50
-25
0
25
50
75
100
125
150
Ambient Temperature Ta (°C)
(*3): Mounted on glass epoxy board. (76.2×114.3×1.6mm:based on EIA/JEDEC standard, 2Layers)
(*4): Mounted on glass epoxy board. (76.2×114.3×1.6mm:based on EIA/JEDEC standard, 4Layers)
(For 4Layers: Applying 74.2×74.2mm inner Cu area and a thermal via hole to a board based on JEDEC standard JESD51-5)
Fig. 8. Power Dissipation vs. Ambient Temperature Characteristics
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Ver.2017-01-25
NJW4132 ApplicationNJW4132
Manual
Technical Information
Application Design Examples
Boost Converter Application Circuit
IC
: NJW4132U2-B
Input Voltage
: VIN=5V
Output Voltage
: VOUT=12V
Output Current
: IOUT=400mA
Oscillation frequency : fosc=700kHz
V IN=5V
L
10 H/3.4A
CIN
10 F/50V
SBD
COUT
22 F/16V
CFB
15pF
V+
SW
GND
R2
220k
R1
20k
NJW4132
EN/
SYNC
RFB
0
V OUT =12V
IN-
EN/SYNC
High: ON
Low: OFF
(Standby)
Reference
IC
L
SBD
CIN
COUT
CFB
RFB
R1
R2
Ver.2017-01-25
Qty.
1
1
1
1
1
1
1
1
1
Part Number
NJW4132U2-B
CDRH8D28HPNP-100N
CMS16
10 F
22 F
15pF
0 (Short)
20k
220k
Description
Internal 45V MOSFET SW.REG. IC
Inductor 10 H, 3.4A
Schottky Diode 40V, 3A
Ceramic Capacitor 3225 10 F, 50V, X5R
Ceramic Capacitor 3225 22 F, 16V, B
Ceramic Capacitor 1608 15pF, 50V, CH
Optional
Resistor 1608 20k , 1%, 0.1W
Resistor 1608 220k , 1%, 0.1W
Manufacturer
New JRC
Sumida
Toshiba
Murata
Murata
Std.
Std.
Std.
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NJW4132
NJW4132Application Manual
Technical Information
Application Characteristics
Efficiency vs. Output Current
(VIN=5V, VOUT=12V)
100
13.0
f=700kHz
L=10 H
90
f=700kHz
L=10 H
12.8
Output Voltage VOUT (V)
80
Efficiency (%)
Output Voltage vs. Output Current
(VIN=5V)
70
60
50
40
30
20
10
12.6
12.4
12.2
12.0
11.8
11.6
11.4
11.2
0
11.0
1
10
100
Output Current IOUT (mA)
1000
1
10
100
Output Current IOUT (mA)
1000
[CAUTION]
The specifications on this databook are only
given for information , without any guarantee
as regards either mistakes or omissions. The
application circuits in this databook are
described only to show representative usages
of the product and not intended for the
guarantee or permission of any right including
the industrial rights.
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Ver.2017-01-25