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Número de pieza | OB2276A | |
Descripción | High Performance Current Mode PWM Controller | |
Fabricantes | On-Bright Electronics | |
Logotipo | ||
Hay una vista previa y un enlace de descarga de OB2276A (archivo pdf) en la parte inferior de esta página. Total 11 Páginas | ||
No Preview Available ! OB2276A
High Performance Current Mode PWM Controller
GENERAL DESCRIPTION
OB2276A 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
internally fixed and is 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 and low
standby design with OB2276A.
OB2276A offers complete protection coverage
with auto-recovery including Cycle-by-Cycle
current limiting (OCP), over load protection (OLP),
Brownout protection, VDD over voltage protection
(OVP), over temperature protection (OTP), output
over voltage protection and VDD under voltage
lockout (UVLO). Excellent EMI performance is
achieved with On-Bright proprietary frequency
shuffling technique.
The tone energy at below 22KHZ is minimized in
the design and audio noise is eliminated during
operation.
OB2276A is offered in SOP8 package.
TYPICAL APPLICATION
FEATURES
■ Power on Soft Start Reducing MOSFET Vds
Stress
■ Frequency shuffling for EMI
■ Extended Burst Mode Control For Improved
Efficiency and Minimum Standby Power
Design
■ 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 threshold
setting for constant output power limiting
over universal input voltage range
o Overload Protection (OLP) with auto-
recovery
o Brownout Protection with auto-recovery
o VDD OVP with auto-recovery
o Over Temperature Protection with auto-
recovery
o Output Over Voltage Protection with auto-
recovery
APPLICATIONS
Offline AC/DC flyback converter for
■ Battery Charger
■ Power Adapter
■ Set-Top Box Power Supplies
■ Open-frame SMPS
©On-Bright Electronics
Confidential
-1-
Preliminary Datasheet
OB_DOC_DS_2276A00
1 page OB2276A
High Performance Current Mode PWM Controller
ELECTRICAL CHARACTERISTICS
(TA = 25℃, VDD=18V, unless otherwise noted)
Symbol
Parameter
Supply Voltage (VDD)
Istartup
VDD Start up Current
I_VDD_Operation Operation Current
UVLO(ON)
UVLO(OFF)
Vpull-up
VDD Under Voltage Lockout
Enter
VDD Under Voltage Lockout
Exit (Recovery)
Pull-up PMOS active
OVP(ON)
Over Voltage Protection
Voltage
Vdd_clamp
Feedback Input Section(FB Pin)
VFB_Open
VFB Open Loop Voltage
Avcs
PWM input gain Δ VFB/ Δ
VCS
Maximum duty Max duty cycle @
cycle
VDD=18V,VFB=3V,VCS=0V
Vref_green
Vref_burst_H
Vref_burst_L
The threshold enter green
mode
The threshold exit burst mode
The threshold enter burst
mode
IFB_Short
FB pin short circuit current
VTH_PL
Power Limiting FB Threshold
Voltage
TD_PL
Power limiting Debounce
Time
ZFB_IN
Input Impedance
Current Sense Input(CS Pin)
SST Soft start time
T_blanking
Leading edge blanking time
ZSENSE_IN
Input Impedance
TD_OC
Over Current Detection and
Control Delay
VTH_OC
Vocp_clamping
Oscillator
FOSC
△f_OSC
F_shuffling
△f_Temp
Internal Current Limiting
Threshold Voltage with zero
duty cycle
CS voltage clamper
Normal Oscillation Frequency
Frequency jittering
Shuffling frequency
Frequency
Temperature
Stability
Test Conditions
VDD=UVLO(OFF)-
1V, measure leakage
current into VDD
VDD=18V,VFB=3V,
CS=0V,Cgate=1nF
CS=0V,FB=3V
Ramp up VDD until
gate clock is off
Ivdd=10mA
Short FB pin to GND
and measure current
From Over Current
Occurs till the Gate
driver output starts to
turn off
VDD=18V, FB=3V,
CS=0V
Min
8
19
28.5
32
3.9
75
80
0.65
62
Typ
3
1.8
9
20
13
30
34
4.2
2
80
1.65
1.25
1.15
0.2
3.7
88
16
4
220
40
100
0.7
0.9
65
+/-4
50
1
Max Unit
20 uA
2.5 mA
10 V
21 V
V
31.5 V
36 V
V
V/V
85 %
V
V
V
mA
V
96 ms
kΩ
ms
ns
kΩ
ns
0.75 V
V
68 kHz
%
Hz
%
©On-Bright Electronics
Confidential
-5-
Preliminary Datasheet
OB_DOC_DS_2276A00
5 Page OB2276A
High Performance Current Mode PWM Controller
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.
©On-Bright Electronics
Confidential
- 11 -
Preliminary Datasheet
OB_DOC_DS_2276A00
11 Page |
Páginas | Total 11 Páginas | |
PDF Descargar | [ Datasheet OB2276A.PDF ] |
Número de pieza | Descripción | Fabricantes |
OB2276 | High Performance Current Mode PWM Controller | On-Bright |
OB2276A | High Performance Current Mode PWM Controller | On-Bright Electronics |
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