GENERAL DESCRIPTION
OB5269 is a highly integrated current mode PWM control IC with high voltage start up, optimized for
high performance, low standby power
consumption and cost effective offline flyback converter applications.
PWM switching frequency at normal operation is
internally fixed and is trimmed to a tight range. At
no load or light load condition, the IC operates in
extended ‘burst mode’ to minimize switching loss.
Very low standby power consumption and very
high conversion efficiency is thus achieved.
High voltage startup is implemented in OB5269,
which features with short startup time and low
standby current.
OB5269 offers complete protection coverage with
auto-recovery including Cycle-by-Cycle current
limiting (OCP), over load protection (OLP), and
VDD under voltage lockout (UVLO). It also
provides the protections with latched shut down
including over temperature protection (OTP), and
over voltage (fixed or adjustable) protection (OVP).
Excellent EMI performance is achieved with On-Bright proprietary frequency shuffling technique.
The tone energy at below 22KHZ is minimized to avoid audio noise during operation. OB5269 is offered in SOP8 package.
FEATURES
■ High Voltage Startup
■ Power on Soft Start Reducing MOSFET Vds Stress ■ Frequency shuffling for EMI
■ Extended Burst Mode Control For Improved Efficiency and Minimum Standby Power ■ Audio Noise Free Operation ■ Fixed 65KHZ Switching Frequency ■ Comprehensive Protection Coverage o VDD Under Voltage Lockout with Hysteresis (UVLO) o Cycle-by-cycle over current protection (OCP) o Overload Protection (OLP) with auto-recovery o Over Temperature Protection (OTP) with latch shut down o VDD Over voltage Protection(OVP) with latch shut down o Adjustable OVP through external Zener APPLICATIONS Offline AC/DC flyback converter for ■ Battery Charger ■ Power Adaptor ■ Open-frame SMPS
TYPICAL APPLICATION
张高琨 13760160570
GENERAL INFORMATION
Pin Configuration
The OB5269 is offered in SOP8 package, shown as below.
RT FB CS GND HV NC VDD GATE
Ordering Information
Part Number Description
OB5269CP SOP8, Pb-free
OB5269CPA SOP8, Pb-free in Taping Package Dissipation Rating
Package RθJA(℃/W)
SOP8 150 Absolute Maximum Ratings
Parameter Value
VDD DC Supply Voltage 30V
High-Voltage Pin, HV -0.3 to 500 V
VDD Zener Clamp
Voltage Note
VDD_Clamp+0.1V VDD DC Clamp Current 10 mA
FB Input Voltage -0.3 to 7V
CS Input Voltage -0.3 to 7V
RT Input Voltage -0.3 to 7V
Min/Max Operating
Junction Temperature TJ
-40 to 150 ℃
Min/Max Storage
Temperature Tstg
-55 to 160 ℃
Lead Temperature (Soldering, 10secs)
260 ℃
Note:VDD_Clamp has a nominal value of 32V.
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.
OB5269 X X X
Current Mode PWM Controller with HV
Startup
Package
C:SOP8Package Pb free
P:lead-free
Packing
Blank:Tube
A:Taping
张高琨 13760160570
Marking Information
YWWZZZ OB5269CP
S
Y:Year Code
WW:Week Code(01-52)ZZZ:Lot Code C:SOP8 Package P:Pb-free Package
S:Internal Code(Optional)
TERMINAL ASSIGNMENTS
Pin Num
Pin Name
I/O
Description
1 RT I Dual function pin. Either connected through a NTC resistor to ground for over temperature shutdown/latch control or connected through Zener to
VDD for adjustable over voltage protection
2 FB I
Feedback input pin. The PWM duty cycle is determined by voltage level into this pin and the current-sense signal at CS pin 3 CS
I Current sense input 4 GND P Ground 5 Gate
O Totem-pole gate driver output for power Mosfet 6 VDD P Power Supply 8 HV
P Connected to the line input or bulk capacitor via resistors for startup
RECOMMENDED OPERATING CONDITION
Symbol Parameter
Min/Max Unit VDD VDD Supply Voltage
12 to 23.5 V T A
Operating Ambient Temperature
-20 to 85
℃
张高琨 13760160570
张高琨 13760160570
BLOCK DIAGRAM
ELECTRICAL CHARACTERISTICS
(T A = 25℃, VDD=15V, unless otherwise noted) Symbol Parameter Test Conditions Min Typ. Max Unit IHV Supply current from HV pin
VDD=2V, HV=100V 2 2.8 5 mA leakage
HV pin leakage current after
startup
VDD=15V, HV=500V
10
uA
Supply Voltage (VDD)
Istartup VDD Start up Current VDD=UVLO(OFF)-1V, measure leakage
current into VDD
5 20 uA I_VDD_Operation Operation Current V FB =3V 1.8 2.5mA
UVLO(ON)
VDD Under Voltage Lockout
Enter
8.3 9.3 10.3V UVLO(OFF)
VDD Under Voltage Lockout
Exit (Recovery)
14.3 15.3 16.3V Vpull-up Pull-up PMOS active 12 V Vdd_clamp Ivdd =10mA 30 32 34 V
OVP(ON) Over voltage protection
voltage
FB=3V
Ramp up VDD until gate clock is off
24 26 28 V
Vth_recovery
Auto release threshold
voltage
5 V Vth_latch Latch release threshold 4.2 V Feedback Input Section(FB Pin)
V FB_Open V FB Open Loop Voltage 3.9 5 V
Avcs
PWM input gain ΔVFB/Δ
VCS
1.7 V/V Maximum duty cycle Max duty cycle @
VDD=14V,VFB=3V,VCS=0.3V
75 80 85 %
Vref_green
The threshold enter green
mode
2 V Vref_burst_H The threshold exit burst mode 1.2 V
Vref_burst_L The threshold enter burst
mode
1.1 V
I FB _Short FB pin short circuit current
Short FB pin to GND
and measure current
360 uA V TH _PL Power Limiting FB Threshold
Voltage
3.7 V
T D _PL
Power limiting Debounce
Time
80 88 96 mSec Z FB _IN Input Impedance 17 Kohm Current Sense Input(CS Pin) SST Soft start time 4 ms T_blanking Leading edge blanking time 320 ns Z SENSE _IN Input Impedance 40 Kohm
T D _OC Over Current Detection and Control Delay From Over Current
Occurs till the gate
driver output starts to
turn off
60 nSec
V TH _OC Internal Current Limiting
Threshold Voltage with zero duty cycle
0.72 0.75 0.78V
Vocp_clamping CS voltage clamper 0.95 V Oscillator
张高琨 13760160570
OB5269
High Voltage Green Mode PWM Controller
F OSC
Normal Oscillation Frequency VDD=15V, FB=3V, 60 65 70 KHZ △f_OSC Frequency jittering +/-4 % F_shuffling Shuffling frequency 32 Hz
△f_Temp Frequency Temperature
Stability
1 % △f_VDD Frequency Voltage Stability 1 % F_Burst Burst Mode Switch Frequency
22
KHZ
Gate driver VOL
Output low level @ VDD=15V,
Io=20mA
1 V
VOH
Output high level @
VDD=15V, Io=20mA
8 V V_clamping Output clamp voltage 13 V
T_r Output rising time 1V ~ 10V
@ CL=1000pF
70 nS
T_f Output falling time 10V ~ 1V
@ CL=1000pF
30 nS
Over temperature protection IRT Output current of RT pin 95 100 105uA Vth_OTP Threshold voltage for OTP 0.95 1 1.05V Td_OTP OTP debounce time 8 Cycle VRT_FL Voltage at floating RT pin 2.6 V
Vth_OVP
External OVP threshold
voltage
3.6 V Td_OVP External OVP debounce time 8 Cycle
张高琨 13760160570
张高琨 13760160570CHARACTERIZATION PLOTS
VDD = 15V, TA = 25℃ condition applies if not otherwise noted.
OPERATION DESCRIPTION
OB5269 is a highly integrated current mode PWM control IC optimized for high performance, low standby power consumption and cost effective offline flyback converter applications. The ‘Extended burst mode’ control greatly reduces the standby power consumption and helps the design easily to meet the international power conservation requirements.
?Internal High Voltage Startup and Under Voltage Lockout (UVLO)
OB5269 integrates HV startup circuit, and provides about 2.8mA current to charge VDD pin during power on state from HV pin. When VDD cap voltage is higher than UVLO(OFF), the charge current is switched off. At this moment, the VDD capacitor provides current to OB5269 until the auxiliary winding of the main transformer starts to provide the operation current.
In general application, a 51KΩ resistor is recommended to be placed in the high voltage path to limit the current.
Fig1 Startup current timing ?Operating Current
The typical operating current of OB5269 is 1.8mA. Good efficiency is achieved with this low operating current together with the ‘Extended burst mode’ control features.
?Soft Start
OB5269 features an internal 4ms soft start to soften the electrical stress occurring in the power supply during startup. It is activated during the power on sequence. As soon as VDD reaches UVLO(OFF), the CS peak voltage is gradually increased from 0V to the maximum level. Every restart up begins with a soft start.
?Frequency shuffling for EMI improvement The frequency shuffling (switching frequency modulation) is implemented in OB5269. The oscillation frequency is modulated so that the tone energy is spread out. The spread spectrum minimizes the conduction band EMI and therefore eases the system design.
?Green-Mode Operation
OB5269 provides green-mode control to reduce the switching frequency in light-load and no-load conditions. V FB, which is derived from the voltage feedback loop, is taken as the reference. Once
V FB is lower than the threshold voltage (Vref_green), switching frequency is continuously decreased to the minimum green-mode frequency
of around 22KHz.
?Extended Burst Mode Operation
At light load or zero load condition, most of the power dissipation in a switching mode power supply is from switching loss in the MOSFET, the core loss of the transformer and the loss in the snubber circuit. The magnitude of power loss is in proportion to the switching frequency. Lower switching frequency leads to the reduction on the power loss and thus conserves the energy.
The switching frequency is internally adjusted at no load or light load condition. The switching frequency is reduced at light/no load condition to improve the conversion efficiency. At light load or no load condition, the FB input drops below burst mode threshold voltage (Vref_burst_L) and device enters Burst Mode control. The gate driver output switches only when FB voltage is higher than the threshold voltage (Vref_burst_H) to output an on state. Otherwise the gate drive remains at off state to minimize the switching loss and reduces the standby power consumption to the greatest extend.
The switching frequency control also eliminates the audio noise at any loading conditions. ?Oscillator Operation
The switching frequency is internally fixed at 65KHZ. No external frequency setting components are required for PCB design simplification.
张高琨 13760160570
OB5269
High Voltage Green Mode PWM Controller
? Current Sensing and Leading Edge Blanking Cycle-by-Cycle current limiting is offered in OB5269 current mode PWM control. The switching current is detected by a sense resistor connected to the CS pin. An internal leading edge blanking circuit chops off the sensed voltage spikes due to snubber diode reverse recovery and surge gate current of power MOSFET at initial internal power MOSFET on state. The current limiting comparator is disabled and cannot turn off the internal power MOSFET during the blanking period. The PWM duty cycle is determined by the current sense input voltage and the FB input voltage.
? 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 eliminates the sub-harmonic oscillation and thus reduces the output ripple voltage.
? Driver
The power MOSFET is driven by a dedicated gate driver for power switching control. Too weak gate driver results in higher conduction and switch loss of MOSFET while too strong gate driver results the compromise of EMI.
A good tradeoff is achieved through the built-in totem pole gate design with right output strength and dead time control. The low idle loss and good EMI system design is achieved with this dedicated control scheme.
? Protection Controls
Good power supply system reliability is achieved with auto-recovery protection features including Cycle-by-Cycle current limiting (OCP), Over Load Protection (OLP), and Under Voltage Lockout on VDD (UVLO), and latched shutdown features including over temperature protection (OTP) and VDD over voltage protection (OVP).
With On-Bright proprietary technology, the OCP is line voltage compensated to achieve constant output power limit over the universal input voltage range.
At overload condition when FB input voltage exceeds power limit threshold value for more than TD_PL, control circuit shuts down the converter. It restarts when VDD voltage drops below Vth_recovery. For protection with latched shut down mode, control circuit shutdowns (latch) the power MOSFET when an Over Temperature condition or Over Voltage condition is detected until VDD drops below Vth_latch , and device enters power on restart-up sequence thereafter .
张高琨 13760160570
PACKAGE MECHANICAL DATA
Dimensions In Millimeters Dimensions In Inches Symbol
Min Max Min Max
A 1.350 1.750 0.053 0.069 A1 0.050 0.250 0.002 0.010 A2 1.250 1.650 0.049 0.065 b 0.310 0.510 0.012 0.020 c 0.170 0.250 0.006 0.010
D 4.700 5.150 0.185 0.203
E 3.800 4.000 0.150 0.157 E1 5.800 6.200 0.228 0.244 e 1.270 (BSC) 0.05 (BSC)
L 0.400 1.270 0.016 0.050 θ 0o 8o 0o 8o
张高琨 13760160570
张高琨 13760160570
IMPORTANT NOTICE
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.
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.
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.
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.