OB3399
High Precision Offline Primary-Side PWM Controller
FEATURES
OB3399 is a primary side regulation off-line LED
lighting controller which can achieve accurate LED
current. It significantly simplifies LED lighting
system design by eliminating the secondary side
feedback circuitry. Proprietary Constant Voltage
(CV) and Constant Current (CC) control is
integrated as shown in the figure below.
The LED current (CC control) can be adjusted
externally by the resistor Rs at CS pin.
OB3399
offers
comprehensive
protection
coverage with auto-recovery features including
Cycle-by-Cycle current limiting, VDD clamp and
UVLO. Excellent EMI performance is achieved
with On-Bright proprietary frequency shuffling
technique.
OB3399 is offered in SOT23-6 package.
High Precise Constant Current Regulation at
Universal AC input
Primary-side Sensing and Regulation Without
TL431 and Opto-coupler
Adjustable Constant Current and Output
Power Setting
Adjustable Constant Voltage Load
Compensation
Built-in Primary Winding Inductance
Compensation
Built-in Leading Edge Blanking (LEB)
Cycle-by-Cycle Current Limiting
VDD Under Voltage Lockout with Hysteresis
(UVLO)
Latched over temperature protection (OTP)
VDD Clamp
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GENERAL DESCRIPTION
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APPLICATIONS
co
nf
Low Power AC/DC offline SMPS for
LED applications
Fig.1. Typical CC/CV Curve
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TYPICAL APPLICATION
©On-Bright Electronics
Confidential
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Preliminary Datasheet
OB_DOC_DS_339903
OB3399
High Precision Offline Primary-Side PWM Controller
GENERAL INFORMATION
Pin Configuration
The pin map is shown as below for SOT23-6.
1
6
5
2
RL
to
CS
GND
-55 to 150 ℃
260 ℃
Note: Stresses beyond those listed under “absolute maximum
ratings” may cause permanent damage to the device. These
are stress ratings only, functional operation of the device at
these or any other conditions beyond those indicated under
“recommended operating conditions” is not implied. Exposure
to absolute maximum-rated conditions for extended periods
may affect device reliability.
Ordering Information
Part Number
Description
OB3399MP
SOT23-6, Halogen-free, T&R
Recommended Operating Condition
Symbol Parameter
Range
VDD
VDD Supply Voltage
12 to 25 V
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Package Dissipation Rating
Package
RθJA (℃/W)
SOT23-6
200
-40 to 85 ℃
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4
-40 to 150 ℃
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3
VDD
FB
Value
-0.3 to VDD_clamp
-0.3 to 25V
-0.3 to 7V
-0.3 to 7V
-0.3 to 7V
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GATE
Absolute Maximum Ratings
Parameter
VDD Voltage
Gate Voltage
CS Input Voltage
FB Input Voltage
RL input voltage
Min/Max Operating Junction
Temperature TJ
Operating
Ambient
Temperature TA
Min/Max Storage
Temperature Tstg
Lead Temperature
(Soldering, 10secs)
©On-Bright Electronics
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Preliminary Datasheet
OB_DOC_DS_339903
OB3399
High Precision Offline Primary-Side PWM Controller
Marking Information
Pin Name
GATE
CS
VDD
I/O
O
I
P
4
FB
I
5
6
RL
GND
Description
Gate driver output
Current sense input.
Power Supply
Connected to resistor divider from primary winding or auxiliary winding
to reflect output voltage.
Load regulation configuration pin
Ground
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Pin Num
1
2
3
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TERMINAL ASSIGNMENTS for OB3399
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Y:Year Code
WW:Week Code(01-52)
ZZZ: Lot code
S: Internal code
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399YWW
. ZZZ S
O
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Br
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IO
P
©On-Bright Electronics
Confidential
3
Preliminary Datasheet
OB_DOC_DS_339903
OB3399
High Precision Offline Primary-Side PWM Controller
BLOCK DIAGRAM
VDD
POR
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UVLO
CC/CV
Controller
RL
Logic
Gate
Driver
GATE
GND
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FB
to
CS
©On-Bright Electronics
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-4-
Preliminary Datasheet
OB_DOC_DS_339903
OB3399
High Precision Offline Primary-Side PWM Controller
ELECTRICAL CHARACTERISTICS
(TA = 25℃, VDD=18V, if not otherwise noted)
Symbol
Parameter
Test Conditions
Min
Typ. Max
Unit
uA
Supply Voltage (VDD) Section
VDD=UVLO_OFF-1V
4
I DD op
Operation Current
Operation supply
current
FB=1V, CS=0V,
VDD= 20V
0.65 1
mA
UVLO(ON)
VDD Under Voltage Lockout Enter
VDD falling
7.3
8.3
V
UVLO(OFF)
VDD Under Voltage Lockout Exit
VDD rising
15.5
16.5 17.5
V
VDD_clamp
Maximum VDD operation voltage
IDD=20mA
25
V
500
ns
500 508
mV
100
ns
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Startup Current
to
I startup
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Current Sense Input Section
Leading edge blanking time
Vth_oc
Over current threshold
Td_oc
Over current protection propagation delay
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TLEB
Frequency Section
Freq_MaxNote
492
20
9.3
IC Maximum frequency
Toff_min
Minimum Toff
4.0
us
F_min
Minimum frequency
1
KHz
co
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1
103
KHz
Error Amplifier section
Gain
Reference voltage for EA
1.164 1.2 1.236 V
ig
ht
Vref
Vth_OVP
DC gain of EA
40
Load OVP threshold voltage
1.4
V
155
℃
Br
On chip Over temperature Section
n-
T_otp
latched over temperature protection trigger
point
Gate Driver Section
Output low level @ VDD=14V, Io=5mA
VOH
Output high level @ VDD=14V, Io=20mA
V_clamping
Output clamp voltage
10
V
T_r
Output rising time 1V~ 9V@ CL=500pF
95
ns
T_f
Output falling time 9V~1V@ CL=500pF
50
ns
O
VOL
1
6
V
V
Note:
Freq_Max indicates IC internal maximum clock frequency. In system application, the maximum operation frequency of 103KHz
nominal occurs at maximum output power or the transition point from CV to CC.
©On-Bright Electronics
Confidential
-5-
Preliminary Datasheet
OB_DOC_DS_339903
OB3399
High Precision Offline Primary-Side PWM Controller
CHARACTERIZATION PLOTS
Istartup(uA) vs Tem perature
Vdd(V) vs Ivdd(uA)
7
Ivdd(uA)
800
600
400
200
5.8
4.6
3.4
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Istartup(uA)
1000
2.2
1
0
7
9
11
13
15
17
-40
19
-10
80
110
140
to
UVLO(ON)(V) vs Tem perature
UVLO(OFF)(V) vs Tem perature
18
UVLO(OFF)(V)
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9
8.8
8.4
8.2
-40
-10
20
50
17.6
17.2
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8.6
8
80
110
140
16.8
16.4
16
-40
-10
co
nf
Temperature(℃)
1.22
1.18
1.14
Br
1.1
-10
20
50
80
110 140
502.5
500.0
497.5
495.0
110 140
25
Temperature(℃)
50
75
100
125
150
Temperature(℃)
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-40
80
505.0
ig
ht
1.26
50
Vth_oc(mV) vs Temperature
Vocp(mV)
1.3
20
Temperature(℃)
Vref(V) vs Tem perature
Vref(V)
50
Temperature(℃)
VDD(V)
UVLO(ON)(V)
20
©On-Bright Electronics
Confidential
-6-
Preliminary Datasheet
OB_DOC_DS_339903
OB3399
High Precision Offline Primary-Side PWM Controller
OPERATION DESCRIPTION
I LED
Startup Current and Start up Control
Startup current of OB3399 is designed to be
very low so that VDD could be charged up
above UVLO threshold and starts up quickly. A
large value startup resistor can therefore be
used to minimize the power loss in application.
Vth _ oc
1
N
4
Rs
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Adjustable CC point and Output Power
In OB3399, the CC point and maximum output
power can be externally adjusted by external
current sense resistor Rs at CS pin as illustrated in
Typical Application Diagram. The output power is
adjusted through CC point change. The larger
Rs, the smaller CC point is, and the smaller output
power becomes, and vice versa as shown in Fig.2.
Vo
co
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Principle of CC Operation
To support OB3399 proprietary CC control,
system needs to be designed in DCM mode for
flyback system (Refer to Typical Application
Diagram on page1). The LED output current
ILED is given by:
I LED
1
2
LP FSW I PK
VO
2
(1)
Io
ig
ht
Figure.2 Adjustable output power by changing Rs
Br
Operation switching frequency
The switching frequency of OB3399 is adaptively
controlled according to the load conditions and the
operation modes. No external frequency setting
components are required. The operation switching
frequency at maximum output power is set to 103K
Hz internally.
For flyback operating in DCM, The maximum
output power is given by
nO
1
2TDemag
(2)
1
2
PO max LP FSW I pk
2
(4)
Where Lp indicate the inductance of primary
winding and Ipk is the peak current of primary
winding.
The principle of CC operation sets the product Lp
and fsw to be a constant, thus the maximum
output power and constant current in CC mode will
not change as primary winding inductance
changes. Up to +/-7% variation of the primary
winding inductance can be compensated.
Figure.1 Primary voltage waveform
Since TDemag is inversely proportional to the
©On-Bright Electronics
Large Rs
Small Rs
Where Lp indicates the inductance of primary
winding, Ipk is the peak current of primary
winding.
Refer to the equation 1, the change of the
primary winding inductance results in the
change of the constant output current. To
compensate the change from variations of
primary winding inductance, the switching
frequency is locked by an internal loop such
that the switching frequency is
FSW
(3)
Where N is the ratio of transformer between
primary winding and secondary winding.
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Operating Current
The Operating current of OB3399 is as low as
0.45mA(Typ.). Typical good efficiency is
achieved with the low operating current
together with ‘Multi-mode’ control features.
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inductance, as a result, the product Lp and fsw is
constant, thus output current will not change as
primary winding inductance changes. Up to ±7%
variation of the primary winding inductance can be
compensated.
The output LED current is
OB3399 is a cost effective PWM controller
optimized for off-line LED lighting applications.
Based on flyback converter topology working in
DCM mode, It operates in primary side sensing
and regulation, thus opto-coupler and TL431
are not required. Proprietary built-in CC control
can achieve high precision LED current
meeting LED lighting application requirements.
Confidential
-7-
Preliminary Datasheet
OB_DOC_DS_339903
OB3399
High Precision Offline Primary-Side PWM Controller
CV/OVP Mode
When LED string is open, an output voltage
condition is monitored independently by the
voltage at FB pin. During normal operation, the
voltage at FB pin is regulated at 1.2V (typ.),
with dummy load over Pmin.
to
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CV Load Compensation
OB3399 features load compensation function to
achieve good CV load regulation. It can be
programmed by adjusting the resistance of R3 at
RL pin to compensate the output voltage deviation
as shown in Figure 4.
The percentage of maximum compensation is
V
(1 / R3) ( R1 // R 2) 106
100%
Vout
1.2
V is load compensation voltage and Vout is
output voltage;
VOUT
N S R1 R 2
V ref
NA
R2
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Figure.3 FB Section Circuit
_ CV
Pmin
1 Vth _ oc
2 R CS
2
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R1 —the value suggested is 50~200Kohms
R2 —the value suggested is 3~10Kohms
F min L priamry
Current Sensing and Leading Edge Blanking
Cycle-by-Cycle current limiting is offered in
OB3399. The switch current is detected by a
sense resistor into the CS pin. An internal leading
edge blanking circuit chops off the sensed voltage
spike at initial power MOSFET. The PWM duty
cycle is determined by the current sense input
voltage and the EA output voltage.
co
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Vth_oc — Over current protection threshold
voltage
Fmin — Minimum switching frequency, which is
1KHz (typ.)
If the dummy load is less than Pmin, the output
voltage rises up. If the voltage at FB pin
exceeds a threshold of approximately 1.4V
(typical), the over-voltage protection function is
activated and the switching is turned off
immediately.
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ht
Protection Control
Good power supply system reliability is achieved
with its rich protection features including
Cycle-by-Cycle current limiting (OCP), VDD clamp,
on-chip OTP, and Under Voltage Lockout on VDD
(UVLO).
N S R1 R 2
V vth _ OVP
NA
R2
Br
V OVP
Latched Over Temperature Protection
Over temperature protection is offered in OB3399.
When temperature of the device rises over 155℃
(typical), the switching frequency will decrease to
half. And the state will be kept until the device
restarts.
VDD is supplied by transformer primary winding
output. The output of OB3399 is shut down when
VDD drops below UVLO (ON) limit and the power
converter enters power on start-up sequence
thereafter.
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CC Line Regulation
Adjust the R1 for better CC line regulation,
while driving different type MOSFET. The
larger MOSFET, the smaller R1 needed. R1
allow the change from 50K to 200K ohms to
cover all the applications. If the resistance is
too large, it causes the interference due to the
floating ground, too small resistance results the
efficiency decreased at HV AC line.
©On-Bright Electronics
Figure.4 CV load compensation
Confidential
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Preliminary Datasheet
OB_DOC_DS_339903
OB3399
High Precision Offline Primary-Side PWM Controller
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PACKAGE MECHANICAL DATA
O
Symbol
A
A1
A2
b
c
D
E
E1
e
e1
L
θ
Dimensions In Millimeters
Min
Max
1.000
1.450
0.000
0.150
0.900
1.300
0.300
0.500
0.080
0.220
2.800
3.020
1.500
1.726
2.600
3.000
0.950 (BSC)
1.800
2.000
0.300
0.600
0º
8º
©On-Bright Electronics
Confidential
-9-
Dimensions In Inches
Min
Max
0.039
0.057
0.000
0.006
0.035
0.051
0.012
0.020
0.003
0.009
0.110
0.119
0.059
0.068
0.102
0.118
0.037 (BSC)
0.071
0.079
0.012
0.024
0º
8º
Preliminary Datasheet
OB_DOC_DS_339903
OB3399
High Precision Offline Primary-Side PWM Controller
IMPORTANT NOTICE
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RIGHT TO MAKE CHANGES
On-Bright Electronics Corp. reserves the right to make corrections, modifications, enhancements,
improvements and other changes to its products and services at any time and to discontinue any product
or service without notice. Customers should obtain the latest relevant information before placing orders
and should verify that such information is current and complete.
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WARRANTY INFORMATION
On-Bright Electronics Corp. warrants performance of its hardware products to the specifications applicable
at the time of sale in accordance with its standard warranty. Testing and other quality control techniques
are used to the extent it deems necessary to support this warranty. Except where mandated by
government requirements, testing of all parameters of each product is not necessarily performed.
On-Bright Electronics Corp. assumes no liability for application assistance or customer product design.
Customers are responsible for their products and applications using On-Bright’s components, data sheet
and application notes. To minimize the risks associated with customer products and applications,
customers should provide adequate design and operating safeguards.
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LIFE SUPPORT
On-Bright Electronics Corp.’s products are not designed to be used as components in devices intended to
support or sustain human life. On-bright Electronics Corp. will not be held liable for any damages or claims
resulting from the use of its products in medical applications.
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MILITARY
On-Bright Electronics Corp.’s products are not designed for use in military applications. On-Bright
Electronics Corp. will not be held liable for any damages or claims resulting from the use of its products in
military applications.
©On-Bright Electronics
Confidential
- 10 -
Preliminary Datasheet
OB_DOC_DS_339903
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