©On-Bright Electronics Confidential
- 1 - OB_DOC_DS_69CC1
OB2269C
Current Mode PWM ControllerFrequency Shuffling
GENERAL DESCRIPTION
OB2269C is a highly integrated current mode PWM
control IC optimized for high performance, low
standby power and cost effective offline flyback
converter applications.
PWM switching frequency at normal operation is
externally programmable and trimmed to tight range.
At no load or light load condition, the IC operates in
extended ‘burst mode’ to minimize switching loss.
Lower standby power and higher conversion
efficiency is thus achieved.
VDD low startup current and low operating current
contribute to a reliable power on startup design with
OB2269C. A large value resistor could thus be used
in the startup circuit to minimize the standby power.
The internal slope compensation improves system
large signal stability and reduces the possible sub-
harmonic oscillation at high PWM duty cycle output.
Leading-edge blanking on current sense input
removes the signal glitch due to snubber circuit diode
reverse recovery. This greatly helps to reduce the
external component count and system cost in
application.
OB2269C offers complete protection coverage with
automatic self-recovery feature including Cycle-by-
Cycle current limiting (OCP), over load protection
(OLP), over temperature protection (OTP), VDD
over voltage protection (OVP) and under voltage
lockout (UVLO). The Gate-drive output is clamped
at 18V to protect the power MOSFET.
In OB2269C, OCP threshold slope is internally
optimized to reach constant output power limit over
universal AC input range.
Excellent EMI performance is achieved with On-
Bright proprietary frequency shuffling technique
together with soft switching control at the totem pole
gate drive output.
The tone energy at below 20KHZ is minimized in
operation. Consequently, audio noise performance is
greatly improved.
OB2269C is offered in both SOP-8 and DIP-8
packages.
FEATURES
■ On-Bright Proprietary Frequency Shuffling
Technology for Improved EMI Performance
■ Extended Burst Mode Control For Improved
Efficiency and Minimum Standby Power Design
■ Audio Noise Free Operation
■ External Programmable PWM Switching
Frequency
■ Internal Synchronized Slope Compensation
■ Low VIN/VDD Startup Current(6.5uA) and Low
Operating Current (2.3mA)
■ Leading Edge Blanking on Current Sense Input
■ Complete Protection Coverage With Auto Self-
Recovery
o External Programmable Over Temperature
Protection (OTP)
o With or Without On-chip VDD OVP for
System OVP
o Under Voltage Lockout with Hysteresis
(UVLO)
o Gate Output Maximum Voltage Clamp (18V)
o Line Compensated Cycle-by-Cycle Over-
current Threshold Setting For Constant Output
Current Limiting Over Universal Input Voltage
Range (OCP)
o Over Load Protection. (OLP)
APPLICATIONS
Offline AC/DC flyback converter for
■ Laptop Power Adaptor
■ PC/TV/Set-Top Box Power Supplies
■ Open-frame SMPS
■ Battery Charger
TYPICAL APPLICATION
On
-B
ri
gh
t
Co
nf
id
en
ti
al
t
o
Ly
co
n
(志
恒
通
电
子
)
©On-Bright Electronics Confidential
- 2 - OB_DOC_DS_69CC1
OB2269C
Current Mode PWM ControllerFrequency Shuffling
GENERAL INFORMATION
Pin Configuration
The OB2269C is offered in DIP and SOP packages
shown as below.
Ordering Information
Part Number Description
OB2269CAP With Frequency Shuffling,
DIP8, Pb-free
OB2269CAPV With Frequency Shuffling,
DIP8, Pb-free, no OVP
OB2269CCP With Frequency Shuffling,
SOP8, Pb-free
OB2269CCPV With Frequency Shuffling,
SOP8, Pb-free, no OVP
Package Dissipation Rating
Package RθJA (°C/W)
DIP8 90
SOP8 150
Absolute Maximum Ratings
Parameter Value
VDD/VIN DC Supply
Voltage
30 V
VDD Zener Clamp
VoltageNote
VDD_Clamp+0.1V
VDD Clamp Continuous
Current
10 mA
VFB Input Voltage -0.3 to 7V
VSENSE Input Voltage to Sense
Pin
-0.3 to 7V
VRT Input Voltage to RT Pin -0.3 to 7V
VRI Input Voltage to RI Pin -0.3 to 7V
Min/Max Operating Junction
Temperature TJ
-20 to 150 oC
Min/Max Storage
Temperature Tstg
-55 to 150 oC
Lead Temperature (Soldering,
10secs)
260 oC
Note: VDD_Clamp has a nominal value of 35V.
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.
On
-B
ri
gh
t
Co
nf
id
en
ti
al
t
o
Ly
co
n
(志
恒
通
电
子
)
©On-Bright Electronics Confidential
- 3 - OB_DOC_DS_69CC1
OB2269C
Current Mode PWM ControllerFrequency Shuffling
Marking Information
TERMINAL ASSIGNMENTS
Pin Num Pin Name I/O Description
1 GND P Ground
2 FB I Feedback input pin. PWM duty cycle is determined by voltage level into this
pin and current-sense signal level at Pin 6.
3 VIN I Connected through a large value resistor to rectified line input for Startup IC
supply and line voltage sensing.
4 RI I Internal Oscillator frequency setting pin. A resistor connected between RI
and GND sets the PWM frequency.
5 RT I Temperature sensing input pin. Connected through a NTC resistor to GND.
6 SENSE I Current sense input pin. Connected to MOSFET current sensing resistor
node.
7 VDD P DC power supply pin.
8 GATE O Totem-pole gate drive output for power MOSFET.
On
-B
ri
gh
t
Co
nf
id
en
ti
al
t
o
Ly
co
n
(志
恒
通
电
子
)
©On-Bright Electronics Confidential
- 4 - OB_DOC_DS_69CC1
OB2269C
Current Mode PWM ControllerFrequency Shuffling
BLOCK DIAGRAM
RECOMMENDED OPERATING CONDITION
Symbol Parameter Min Max Unit
VDD VDD Supply Voltage 12 23 V
RI RI Resistor Value 24 31 Kohm
TA Operating Ambient Temperature -20 85 oC
On
-B
ri
gh
t
Co
nf
id
en
ti
al
t
o
Ly
co
n
(志
恒
通
电
子
)
©On-Bright Electronics Confidential
- 5 - OB_DOC_DS_69CC1
OB2269C
Current Mode PWM ControllerFrequency Shuffling
ESD INFORMATION
Symbol Parameter Test Conditions Min Typ Max Unit
HBMNote Human Body Model
on All Pins Except
VIN and VDD
MIL-STD 3 KV
MM Machine Model on
All Pins
JEDEC-STD 250 V
Note: HBM all pins pass 3KV except High Voltage Input pin. The details are VIN passes 1kV, VDD passes 1.5KV, all other I/Os pass 3KV.
In system application, High Voltage Input pin is either a high impedance input or connected to a cap. The lower rating has minimum impacts
on system ESD performance.
ELECTRICAL CHARACTERISTICS
(TA = 25OC, VDD=16V, RI=24Kohm if not otherwise noted)
Symbol Parameter Test Conditions Min Typ Max Unit
Supply Voltage (VDD)
I_VDD_Startup VDD Start up
Current
VDD =15V, Measure
current into VDD
6.5 20 uA
I_VDD_Operation Operation Current VFB=3V 2.3 mA
UVLO(Enter) VDD Under Voltage
Lockout Enter
9.5 10.5 11.5 V
UVLO(Exit) VDD Under Voltage
Lockout Exit
(Startup)
15.5 16.5 17.5 V
OVP(ON)*Optional VDD Over Voltage
Protection Enter
23.5 25 26.5 V
OVP(OFF)*Optional VDD Over Voltage
Protection Exit
(Recovery)
21.5 23 24.5 V
OVP_Hys*Optional OVP Hysteresis OVP(ON)-OVP(OFF) 2 V
TD_OVP VDD OVP
Debounce time
80 uSec
VDD_Clamp VDD Zener Clamp
Voltage
I(VDD ) = 5mA 35 V
Feedback Input Section(FB Pin)
AVCS PWM Input Gain ΔVFB /ΔVcs 2.8 V/V
VFB_Open VFB Open Voltage 5.9
V
IFB_Short FB pin short circuit
current
Short FB pin to GND,
measure current
0.80 mA
VTH_0D Zero Duty Cycle FB
Threshold Voltage
0.95 V
VTH_BM Burst Mode FB
Threshold Voltage
1.7 V
VTH_PL Power Limiting FB
Threshold Voltage
4.4 V
TD_PL Power limiting
Debounce Time
80 mSec
ZFB_IN Input Impedance 7.2 Kohm
Current Sense Input(Sense Pin)
T_blanking Sense Input Leading
Edge Blanking Time
250 nS
ZSENSE_IN Sense Input 30 Kohm
On
-B
ri
gh
t
Co
nf
id
en
ti
al
t
o
Ly
co
n
(志
恒
通
电
子
)
©On-Bright Electronics Confidential
- 6 - OB_DOC_DS_69CC1
OB2269C
Current Mode PWM ControllerFrequency Shuffling
Impedance
TD_OC Over Current
Detection and
Control Delay
CL=1nf at GATE, 120 nSec
VTH_OC_0 Current Limiting
Threshold at No
Compensation
I(VIN) = 0uA 0.85 0.90 0.95 V
VTH_OC_1
Current Limiting
Threshold at
Compensation
I(VIN) = 150uA 0.81 V
Oscillator
FOSC Normal Oscillation
Frequency
60 65 70 KHZ
∆f_Temp Frequency
Temperature
Stability
-20oC to 100oC 2 %
∆f_VDD Frequency Voltage
Stability
VDD = 12-25V 2 %
RI_range Operating RI Range 12 24 60 Kohm
V_RI_open RI open voltage 2.0 V
F_BM Burst Mode Base
Frequency
22 KHZ
DC_max Maxmum Duty
Cycle
75 80 85 %
DC_min Minimum Duty
Cycle
- - 0 %
Gate Drive Output
VOL Output Low Level Io = -20 mA 0.3 V
VOH Output High Level Io = +20 mA 11 V
VG_Clamp Output Clamp
Voltage Level
VDD=20V 18 V
T_r Output Rising Time CL = 1nf 120 nSec
T_f Output Falling Time CL = 1nf 50 nSec
Over Temperature Protection
I_RT Output Current of
RT pin
70 uA
VTH_OTP OTP Threshold
Voltage
1.015 1.065 1.115 V
VTH_OTP_off OTP Recovery
Threshold Voltage
1.165 V
TD_OTP OTP De-bounce
Time
100 uSec
V_RT_Open RT Pin Open
Voltage
3.5 V
Frequency Shuffling
∆f_OSC Frequency
Modulation range
/Base frequency
-3 3 %
Freq_Shuffling Shuffling Frequency RI = 24Kohm 32 HZ
On
-B
ri
gh
t
Co
nf
id
en
ti
al
t
o
Ly
co
n
(志
恒
通
电
子
)
©On-Bright Electronics Confidential
- 7 - OB_DOC_DS_69CC1
OB2269C
Current Mode PWM ControllerFrequency Shuffling
CHARACTERIZATION PLOTS
VDD Start-up Current vs. Voltage
0
1
2
3
4
5
6
7
8
9
10
11
0 2 4 6 8 10 12 14 16
VDD VOLTAGE (V)
S
ta
rt-
up
C
ur
re
nt
(u
A
)
VDD Startup Current vs Temperature
0
2
4
6
8
-25 5 35 65 95 125
Temperature(C)
Is
ta
rtu
p(
uA
)
VDD UVLO and Operation Current
0
0.5
1
1.5
2
2.5
3
0 2 4 6 8 10 12 14 16 18 20 22 24
VDD Voltage (V)
VD
D
Cu
rr
en
t
(m
A)
VDD Operation Current vs. Load
1
2
3
4
5
6
0 500 1000 1500 2000
Gatedrive Loading (pf)
I(
VD
D)
(
mA
)
Fosc 50Khz Fosc 65Khz Fosc 100Khz
VDD UVLO(enter) vs. Temperature
10.3
10.35
10.4
10.45
10.5
10.55
10.6
-10 10 30 50 70 90 110
Temperature(C)
U
V
LO
(e
nt
er
) (
V
)
VDD UVLO(exit) vs. Temperature
16.4
16.5
16.6
16.7
16.8
16.9
-10 10 30 50 70 90 110
Temperature(C)
U
V
LO
(e
xi
t)
(V
)
On
-B
ri
gh
t
Co
nf
id
en
ti
al
t
o
Ly
co
n
(志
恒
通
电
子
)
©On-Bright Electronics Confidential
- 8 - OB_DOC_DS_69CC1
OB2269C
Current Mode PWM ControllerFrequency Shuffling
Fosc(KHz) vs RI(Kohm)
20
50
80
110
140
12 24 36 48 60
RI(Kohm)
Fo
sc
(K
H
z)
Fosc(KHz) vs. Temperature
63.5
64.0
64.5
65.0
65.5
66.0
-20 5 30 55 80 105 130
Temp(C)
Fo
sc
(K
H
z)
Vth_OC vs. I(vin)
0.6
0.7
0.8
0.9
1.0
0 50 100 150 200 250 300
I(vin) (uA)
V
th
_O
C
(V
)
Vth_OC(50KHz)
Vth_OC(65KHz)
I_RT vs. Temperature
70.6
70.8
71
71.2
71.4
-20 0 20 40 60 80 100 120
Temperature(C)
I_
R
T(
uA
)
On
-B
ri
gh
t
Co
nf
id
en
ti
al
t
o
Ly
co
n
(志
恒
通
电
子
)
©On-Bright Electronics Confidential
- 9 - OB_DOC_DS_69CC1
OB2269C
Current Mode PWM ControllerFrequency Shuffling
OPERATION DESCRIPTION
The OB2269C is a highly integrated PWM
controller IC optimized for offline flyback
converter applications. The extended burst mode
control greatly reduces the standby power
consumption and helps the design easily meet the
international power conservation requirements.
• Startup Current and Start up Control
Startup current of OB2269C is designed to be very
low so that VDD could be charged up above
UVLO(exit) threshold level and device starts up
quickly. A large value startup resistor can therefore
be used to minimize the power loss yet reliable
startup in application. For a typical AC/DC adaptor
with universal input range design, a 2 MΩ, 1/8 W
startup resistor could be used together with a VDD
capacitor to provide a fast startup and yet low
power dissipation design solution.
z Operating Current
The Operating current of OB2269C is low at
2.3mA. Good efficiency is achieved with OB2269C
low operating current together with extended burst
mode control schemes.
z Frequency shuffling for EMI improvement
The frequency Shuffling/jittering (switching
frequency modulation) is implemented in
OB2269C. The oscillation frequency is modulated
with a internally generated random source so that
the tone energy is evenly spread out. The spread
spectrum minimizes the conduction band EMI and
therefore eases the system design in meeting
stringent EMI requirement.
z Burst Mode Operation
At zero load or light load condition, most of the
power dissipation in a switching mode power
supply is from switching loss on the MOSFET
transistor, the core loss of the transformer and the
loss on the snubber circuit. The magnitude of
power loss is in proportion to the number of
switching events within a fixed period of time.
Reducing switching events leads to the reduction
on the power loss and thus conserves the energy.
OB2269C self adjusts the switching mode
according to the loading condition. At from no load
to light/medium load condition, the FB input drops
below burst mode threshold level (1.8V). Device
enters Burst Mode control. The Gate drive output
switches only when VDD voltage drops below a
preset level and FB input is active to output an on
state. Otherwise the gate drive remains at off state
to minimize the switching loss thus reduce the
standby power consumption to the greatest extend.
The nature of high frequency switching also
reduces the audio noise at any loading conditions.
z Oscillator Operation
A resistor connected between RI and GND sets the
constant current source to charge/discharge the
internal cap and thus the PWM oscillator frequency
is determined. The relationship between RI and
switching frequency follows the below equation
within the specified RI in Kohm range at nominal
loading operational condition.
)(
)(
1560 Khz
KohmRI
FOSC =
z Current Sensing and Leading Edge
Blanking
Cycle-by-Cycle current limiting is offered in
OB2269C current mode PWM control. The switch
current is detected by a sense resistor into the sense
pin. An internal leading edge blanking circuit chops
off the sense voltage spike at initial MOSFET on
state due to snubber diode reverse recovery so that
the external RC filtering on sense input is no longer
required. The current limit comparator is disabled
and thus cannot turn off the external MOSFET
during the blanking period. PWM duty cycle is
determined by the current sense input voltage and
the FB input voltage.
z Internal Synchronized Slope Compensation
Built-in slope compensation circuit adds voltage
ramp onto the current sense input voltage for PWM
generation. This greatly improves the close loop
stability at CCM and prevents the sub-harmonic
oscillation and thus reduces the output ripple
voltage.
z Over Temperature Protection
A NTC resistor in series with a regular resistor
should connect between RT and GND for
temperature sensing and protection. NTC resistor
value becomes lower when the ambient temperature
rises. With the fixed internal current IRT flowing
through the resistors, the voltage at RT pin
becomes lower at high temperature. The internal
OTP circuit is triggered and shutdown the
MOSFET when the sensed input voltage is lower
than VTH_OTP.
z Gate Drive
On
-B
ri
gh
t
Co
nf
id
en
ti
al
t
o
Ly
co
n
(志
恒
通
电
子
)
©On-Bright Electronics Confidential
- 10 - OB_DOC_DS_69CC1
OB2269C
Current Mode PWM ControllerFrequency Shuffling
OB2269C Gate is connected to the Gate of an
external MOSFET for power switch control. Too
weak the gate drive strength results in higher
conduction and switch loss of MOSFET while too
strong gate drive output compromises the EMI.
Good tradeoff is achieved through the built-in
totem pole gate drive design with right output
strength and dead time control. The low idle loss
and good EMI system design is easier to achieve
with this dedicated control scheme. An internal
18V clamp is added for MOSFET gate protection at
higher than expected VDD input.
z Protection Controls
Good system reliability is achieved with
OB2269C’s rich protection features including
Cycle-by-Cycle current limiting (OCP), Over Load
Protection (OLP), over temperature protection
(OTP), on-chip VDD over voltage protection (OVP,
optional) and under voltage lockout (UVLO).
The OCP threshold value is self adjusted lower at
higher current into VIN pin. This OCP threshold
slope adjustment helps to compensate the increased
output power limit at higher AC voltage caused by
inherent Over-Current sensing and control delay. A
constant output power limit is achieved with
recommended OCP compensation scheme on
OB2269C.
At output overload condition, FB voltage is biased
higher. When FB input exceeds power limit
threshold value for more than 80mS, control circuit
reacts to turnoff the power MOSFET.
Similarly, control circuit shutdowns the power
MOSFET when an Over Temperature condition is
detected. OB2269C resumes the operation when
temperature drops below the hysteresis value.
VDD is supplied with transformer auxiliary
winding output. It is clamped when VDD is higher
than 35V. MOSFET is shut down when VDD drops
below UVLO(enter) limit and device enters power
on startup sequence thereafter.
On
-B
ri
gh
t
Co
nf
id
en
ti
al
t
o
Ly
co
n
(志
恒
通
电
子
)
本文档为【OB2269_icpdf】,请使用软件OFFICE或WPS软件打开。作品中的文字与图均可以修改和编辑,
图片更改请在作品中右键图片并更换,文字修改请直接点击文字进行修改,也可以新增和删除文档中的内容。
该文档来自用户分享,如有侵权行为请发邮件ishare@vip.sina.com联系网站客服,我们会及时删除。
[版权声明] 本站所有资料为用户分享产生,若发现您的权利被侵害,请联系客服邮件isharekefu@iask.cn,我们尽快处理。
本作品所展示的图片、画像、字体、音乐的版权可能需版权方额外授权,请谨慎使用。
网站提供的党政主题相关内容(国旗、国徽、党徽..)目的在于配合国家政策宣传,仅限个人学习分享使用,禁止用于任何广告和商用目的。