DataSheet.es OB2287 Hoja de datos PDF


PDF OB2287 Datasheet ( Hoja de datos )

Número de pieza OB2287
Descripción High Performance Current Mode PWM Controller
Fabricantes On-Bright Electronics 
Logotipo On-Bright Electronics Logotipo
Vista previa
Total 13 Páginas
		
OB2287 datasheet

1 Page

OB2287 pdf
OB2287
High Performance Current Mode PWM Controller
ELECTRICAL CHARACTERISTICS
(TA = 25OC, RI=20K ohm, VDD=16V, if not otherwise noted)
Symbol
Parameter
Supply Voltage (VDD) Section
I_VDD_Startup VDD Start up Current
I_VDD_Ops
UVLO(Enter)
UVLO(Exit)
OVP(Latch)
OVP(De-Latch)
I(Vdd)_latch
TD_OVP
VDD_Clamp
T_Softstart
Operation Current
VDD Under Voltage
Lockout Enter
VDD Under Voltage
Lockout Exit
(Startup)
VDD Over Voltage
Latch Trigger
VDD Latch Release
Voltage Threshold
VDD bleeding current
at latch shutdown
when VDD = 8V
VDD OVP Debounce
time
VDD Zener Clamp
Voltage
Soft Start Time
Feedback Input Section(FB Pin)
AVCS
PWM Input Gain
VFB_Open
VFB Open Voltage
Test Conditions
VDD =15V, Measure
current into VDD
VFB=3V
I(VDD ) = 5 mA
ΔVFB /ΔVcs
VDD=18V
Min Typ Max Unit
5 20 uA
2.3 mA
8 9 10 V
14 15 16 V
26.5 28
6.5
45
29.5 V
V
uA
100 uSec
31 V
16 mSec
2.2 V/V
6V
IFB_Short
VTH_0D
VTH_BM
VTH_PL
TD_PL
ZFB_IN
FB pin short circuit
current
Zero Duty Cycle FB
Threshold Voltage
Burst Mode FB
Threshold Voltage
Power Limiting FB
Threshold Voltage
Power limiting
Debounce Time
Input Impedance
VDD=18V, Short FB pin
to GND, measure current
1.1
1.6
4.4
250
6
Current Sense Input(Sense Pin) Section
T_blanking
Sense Input Leading
Edge Blanking Time
VTH_OC_0
Internal current
limiting threshold
TD_OC
Over Current
Detection and Control
Delay
VDD=18V
Zero duty cycle
CL=1nf at GATE,
350
0.68 0.7
70
Oscillator Section
FOSC Normal Oscillation
Frequency
F(shuffle)/Fosc Frequency shuffling
range
60 65
-4
mA
1V
V
V
mSec
Kohm
nSec
0.72 V
nSec
70 KHZ
4%
©On-Bright Electronics
-5-
Confidential
OB_DOC_DS_8700
Free Datasheet http://www.d

5 Page

OB2287 arduino
OB2287
High Performance Current Mode PWM Controller
An example is to implement system OVP
protection with a latch shutdown function through a
photo coupler and affiliated circuits. When OVP
detection signal connected to RT is lower than
VTH_OTP OB2287 controls system into latch
shutdown. The recovery of the AC/DC system
could only be realized by resetting internal latch
when VDD voltage drops below VDD_De-latch
value. This could be achieved by unplugging/re-
plugging of AC source in AC start-up configuration.
counting cycle begins. The counting time in
OB2287 is 1 second. Therefore, the nominal
operation of OLP is not disturbed.
z Pin floating and short protection
OB2287 provides pin floating protection for RI, CS,
FB, etc., and RI pin short protection. In cases when
the pin are floating or RI pin is shorted to ground,
PWM switching is disabled, thus protect the power
system.
z Brownout protection
By monitoring the voltage level on pin BO during
normal operation, the controller protects the SMPS
against low main condition. When BO voltage level
falls below 1.05V, and if it lasts for about 50ms, the
controller stops pulsing until this level goes back
and the operation resumes. By adjusting the resistor
divider connected between the high input voltage
and this pin, start and stop levels are programmable.
z OCP compensation for CCM/DCM
In OB2287, a proprietary OCP compensation is
provided for better OCP performance in the
universal input range. In conventional OCP
compensation, only the gate delay is compensated.
In OB2287, in addition to that, the mode difference
between CCM and DCM is also compensated, since
in 90VAC the system often works in CCM. In this
way, a more accurate OCP is achieved over the
entire line voltage range.
z Restart timer
In some special applications, such as LCDTV, the
power supply of PWM stage is provided by other
DC source and it is always on. The following
diagram shows an AC/DC part of the LCDTV. The
front end is a PFC stage, followed by a PWM stage.
The PFC stage is controlled by PWM stage. A
stand along standby converter provides the DC
power supply for both PWM and PFC stages.
z Overload Operation
When over load (for example, short circuit) occurs,
a fault is detected. If this fault is present for more
than 250ms, OB2287 enters an auto-recovery soft
burst mode. All pulses are stopped, VDD will drops
below UVLO and the controller will try to restart,
with the power-on soft start. The SMPS resumes
operation if the fault has gone. Otherwise, a burst
sequence starts again.
z Soft Start
OB2287 features an internal 16ms soft start to
soften the constraints occurring in the power supply
during startup. It is activated during the power on
sequence. As soon as VDD reaches UVLO(exit),
the peak current is gradually increased from nearly
zero to the maximum clamping level 0.7V. The soft
start is also activated during OLP sequence. Every
restart attempt is followed by soft start.
In such situations, when the over loading protection
(OLP) occurs, PWM stage will be latched of and it
will not recover since it is powered by the standby
DC supply. OB2287 overcomes this by an internal
restart timer. When OLP occurs, then the timer
begins counting. When counting over, the OLP
states will be cleared. System tends to restart and
auto-recover. If OLP still exists, then another
z Gate Drive
The PWM output 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
16.5V clamp is added for MOSFET gate protection
at higher than expected VDD input.
©On-Bright Electronics
- 10 -
Confidential
OB_DOC_DS_8700
Free Datasheet http://www.datasheetlist.com/

10 Page





PáginasTotal 13 Páginas
PDF Descargar[ OB2287.PDF ]

Enlace url


Hoja de datos destacado

Número de piezaDescripciónFabricantes
OB2283High Performance Current Mode PWM ControllerOn-Bright Electronics
On-Bright Electronics
OB2287High Performance Current Mode PWM ControllerOn-Bright Electronics
On-Bright Electronics
OB2288Highly Integrated Current Mode PWM ControllerOn-Bright Electronics
On-Bright Electronics

Número de piezaDescripciónFabricantes
SSM2604

Low Power Audio Codec.

Analog Devices
Analog Devices
SLG3NB3331

32.768 kHz and MHz GreenCLK.

Silego
Silego
SLA6805M

High Voltage 3 phase Motor Driver IC.

Sanken
Sanken
SDC1742

12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters.

Analog Devices
Analog Devices
SDC1741

12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters.

Analog Devices
Analog Devices


DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares,
permitiéndote verlos en linea o descargarlos en PDF.


Index : 0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z


www.DataSheet.es    |   2018   |  Contacto  |  Buscar