NJU7620
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1
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Ver.2012-08-03
Step-Up/Flyback Switching Regulator IC with Constant Current Control
■ GENERAL DESCRIPTION ■ PACKAGE OUTLINE
■ FEATURES ■ PRODUCT VARIATION
● PWM switching control
● Constant Current Control
● Operating Voltage 2.2V to 8V
● Wide Oscillator Range 300kHz to 1MHz
● Maximum Duty Cycle 90% typ.
● Quiescent Current 800µA typ.
● Soft-Start Function Internal : 16ms typ. or adjustable
● Dead Time Control
● C-MOS Technology
● Package Outline NJU7620RB1 : MSOP8 (TVSP8)*
*MEET JEDEC MO-187-DA / THIN TYPE
■PIN CONFIGURATION
The NJU7620 is a low voltage operation high-speed switching
regulator control IC for step-up and flyback converter, with a
constant current control. It incorporates a totem pole output, which
can drive an external MOS-FET easily. It also incorporates error
amplifier and current sense amplifier, which can allow the constant
voltage/current control for output voltage. Therefore the NJU7620 is
suitable for a LED driving and other CCCV applications up to 10W.
The NJU7620 is available in a small and thin 8-lead MSOP
(TVSP) package.
PIN FUNCTION
1. V+
2. FB
3. IN-1
4. IN-2
5. DTC
6. RT
7. GND
8. OUT
NJU7620RB1
1 8
2 7
3 6
4 5
Over Current Protection
NJU7600
NJU7610
PWM Control
Constant Current Control
NJU7620
NJU7620RB1
(MSOP8 (TVSP8))
NJU7620
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■ BLOCK DIAGRAM
Buffer
0.5V
OSC
0.5
RT
A
UVLO
Soft Start
1V
0.8V
0.2V
OUT
GND RT DTC
RT
FB
V
+
Error AMP
0.2V Current
Sense AMP
IN-1
IN-2
0.74V
PWM
−
1
−
1
NJU7620
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Ver.2012-08-03
■ ABSOLUTE MAXIMUM RATINGS (Ta=25°C)
PARAMETER SYMBOL MAXIMUM RATINGS UNIT
Supply Voltage V+ +9 V
Output Pin Current IO ±50 mA
Power Dissipation PD MSOP8 (TVSP8) :320 mW
Operating Temperature Range TOPR -40 to +85 °C
Storage Temperature Range TSTG -40 to +125 °C
■ RECOMMENDED OPERATING CONDITIONS (Ta=25°C)
PARAMETER SYMBOL MIN. TYP. MAX. UNIT
Operating Voltage V+ 2.2 – 8 V
Oscillator Timing Resistor RT 30 47 120 kΩ
Oscillation Frequency fOSC 300 700 1,000 kHz
■ ELECTRICAL CHARACTERISTICS (V
+=3.3V, RT=47kΩ, Ta=25°C)
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Under Voltage Lockout Block
ON Threshold Voltage VT_ON V
+= L → H 1.9 2.0 2.1 V
OFF Threshold Voltage VT_OFF V
+= H → L 1.8 1.9 2.0 V
Hysteresis Voltage VHYS 60 100 – mV
Soft Start Block
Soft Start Time TSS V
T_ON → Duty=80% 8 16 24 ms
Oscillator Block
RT Pin Voltage VRT -5% 0.5 +5% V
Oscillation Frequency fOSC 630 700 770 kHz
Oscillate Supply Voltage
Fluctuations fDV V
+=2.2V to 8V – 1 – %
Oscillate Temperature
Fluctuations fDT Ta=-40 °C to +85°C – 3 – %
NJU7620
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■ELECTRICAL CHARACTERISTICS (V+=3.3V, RT=47kΩ, Ta=25°C)
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Error Amplifier Block
Reference Voltage 1 VB1 -1.5% 1.00 +1.5% V
Input Bias Current 1 IB1 -0.1 – 0.1
µA
Open Loop Gain 1 AV1 – 80 – dB
Gain Bandwidth Product 1 GB1 – 1 – MHz
IOM+_1 V
FB=1V, VIN-1=0.9V, VIN-2=0.1V 25 55 95 mA
Output Source Current 1 IOM+_2 VFB=1V, VIN-1=0.9V, VIN-2=0.1V,
V+=2.2V 4 9 16 mA
Output Sink Current 1 IOM1- V
FB=1V, VIN-1=1.1V, VIN-2=0.1V 0.10 0.16 0.22 mA
Current Sense Amplifier Block
Reference Voltage 2 VB2 -10% 0.2 +10% V
Input Bias Current 2 IB2 -0.1 – 0.1
µA
Open Loop Gain 2 AV2 – 70 – dB
Gain Bandwidth Product 2 GB2 – 1 – MHz
Output Sink Current 2 IOM2- V
FB=1V, VIN-1=0.9V, VIN-2=0.3V 0.10 0.16 0.22 mA
PWM Comparate Block
VT_0 Duty=0% 0.16 0.22 0.28 V
Input Threshold Voltage VT_50 Duty=50% 0.44 0.5 0.56 V
MAXDUTY_1 V
FB=0.9V 85 90 95 %
Maximum Duty Cycle MAXDUTY_2 V
FB=0.9V, RDTC=47kΩ 40 50 60 %
Output Block
Output High Level
ON Resistance ROH I
O=-20mA – 10 20 Ω
Output Low Level
ON Resistance ROL I
O=+20mA – 5 10 Ω
General Characteristics
Quiescent Current IDD R
L=Non Load – 800 1200 µA
NJU7620
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Ver.2012-08-03
■ TYPICAL APPLICATIONS
Step-Up Converter
IN-2
V+ VOUT
1
CIN
FET
R2
SBD
R1
COUT
L
CNF
RNF
2
3
45
6
7
8
RDTC
CS
IN-1
FB
V+
DTC
RT
GND
OUT
RT
C NJU7620
CCNF
RCNF
GNDOUT
RSC
RCIN
Flyback Converter
IN-2
V+ VOUT
1
CIN
FET
R2
SBD
R1
COUT
T
2
3
4 5
6
7
8
RDTC
CS
IN-1
FB
V+
DTC
RT
GND
OUT
RT
C NJU7620
GNDOUT
RSC
CNF
RNF
CCNF
RCNF
RCIN
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■TYPICAL CHARACTERISTICS
100
1000
10 100
Oscillation Frequency fOSC (kHz)
Oscillation Frequency vs. Timing Resistance
(V+=3.3V, Ta=25
oC)
Timing Resistance R
T (kΩ)
80
85
90
95
100
100 1000
Maximum Duty Cycle
MAXDUTY_1 (%)
Maximum Duty Cycle vs. Oscillator Frequency
(V+=3.3V, Ta=25oC)
Oscillator Frequency f
OSC (kHz)
660
680
700
720
740
0246810
Oscillation Frequency fosc (kHz)
Operating Voltage V
+ (V)
Oscillation Frequency vs. Operating Voltage
(RT=47kΩ, Ta=25oC)
0
20
40
60
80
100
0 20406080100
Duty Cycle MAXDUTY (%)
Dead Time Control Resistance R
DTC (kΩ)
Duty Cycle vs. R
DTC
(V+=3.3V, RT=47kΩ, Ta=25oC)
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■TYPICAL CHARACTERISTICS
0.996
0.998
1
1.002
1.004
0246810
Reference Voltage1 VB1 (V)
Operating Voltage V
+ (V)
Error Amplifier Block
Reference Voltage1 vs. Operating Voltage
(Ta=25oC)
0.196
0.198
0.2
0.202
0.204
0246810
Reference Voltage2 VB2 (V)
Operating Voltage V
+ (V)
Current Sense Amplifier Block
Reference Voltage2 vs. Operating Voltage
(Ta=25oC)
0
200
400
600
800
1000
1200
1400
0246810
Quiescent Current IDD (µA)
Operating Voltage V
+ (V)
Quiescent Current vs. Operating Voltage
(RT=47kΩ, RL=Non Load, Ta=25
oC)
(V+=3.3V, Gain=40dB, Ta=25
oC)
0
15
30
45
60
0
45
90
135
180
0.1 1 10 100 1000 10000
Error Amplifier Block
Voltage Gain, Phase vs. Frequency
Phase Φ (deg)
Frequency f (kHz)
Voltage Gain Av (dB)
Phase
Gain
NJU7620
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■TYPICAL CHARACTERISTICS
0
2
4
6
8
10
12
14
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Output High Level ON Resistance
ROH (Ω)
Output Block
Output High Level ON Resistance
vs. Temperature (Io=-20mA)
V+=3.3V
V+=1.95V
V+=8V
0
2
4
6
8
10
12
14
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Output Low Level ON Resistance
ROL (Ω)
Output Block
Output Low Level ON Resistance
vs. Temperature (Io=+20mA)
V+=3.3V
V+=1.95V
V+=8V
1
10
100
1000
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Output Source Current I
OM+ (mA)
Error Amplifier Block
Output Source Current1 vs. Temperature
(VFB=1V, VIN-1=0.9V, VIN-2=0.1V)
V+=3.3V
V+=1.95V
V+=8V
0
0.05
0.1
0.15
0.2
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Output Sink Current IOM- (mA)
Error Amplifier, Current Sense Amplifier Block
Output Sink Current vs. Temperature
V+=1.95V, 3.3V, 8V
8
10
12
14
16
18
20
22
24
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Soft Start Time Tss (ms)
Soft Start Time vs. Temperature
(V+=3.3V)
NJU7620
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Ver.2012-08-03
■TYPICAL CHARACTERISTICS
0.99
0.995
1
1.005
1.01
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Reference Voltage1 VB1 (V)
Error Amplifier Block
Reference Voltage1 vs. Temperature
(V+=3.3V)
0.19
0.195
0.2
0.205
0.21
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Reference Voltage2 VB2 (V)
Current Sense Amplifier Block
Reference Voltage2 vs. Temperature
(V+=3.3V)
640
660
680
700
720
740
760
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Oscillator Frequency fOSC (kHz)
Oscillator Frequency vs. Temperature
(V+=3.3V, RT=47kΩ)
40
50
60
70
80
90
100
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Muximum Duty Cycle
MAXDUTY (%)
Muximum Duty Cycle vs. Temperature
(V+=3.3V)
MAXDUTY_1
MAXDUTY_2
1.86
1.9
1.94
1.98
2.02
2.06
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Threshold Voltage (V)
Under Voltage Lockout Block
vs. Temperature
VT_OFF
VT_ON
0
200
400
600
800
1000
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Quiescent Current IDD (µA)
Quiescent Current vs. Temperature
(V+=3.3V, RT=47kΩ)
NJU7620
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-Ver.2012-08-03
MEMO
[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.
