Datasheet OB2263MP, OB2263CP Datasheet (On-Bright) [ru]

OB2263

Current Mode PWM Controller

GENERAL DESCRIPTION

OB2263 is a highly integrated current mode PWM
control IC optimized for high performance, low
standby power and cost effective offline flyback
converter applications in sub 30W range.
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
OB2263. 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 sub­harmonic oscillation at high PWM duty cycle output.
Leading-edge blanking on current sense(CS) input
removes the signal glitch due to snubber circuit diode
reverse recovery and thus greatly reduces the external
component count and system cost in the design.
OB2263 offers complete protection coverage with
automatic self-recovery feature including Cycle-by­Cycle current limiting (OCP), over load protection
(OLP), VDD over voltage clamp and under voltage
lockout (UVLO). The Gate-drive output is clamped
to maximum 18V to protect the power MOSFET.
Excellent EMI performance is achieved with On­Bright proprietary frequency shuffling technique
together with soft switching control at the totem pole
gate drive output.

Frequency Shuffling

Tone energy at below 20KHZ is minimized in the
design and audio noise is eliminated during operation.
OB2263 is offered in SOT23-6, 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 VDD Startup Current and Low Operating
Current (1.4mA)
Leading Edge Blanking on Current Sense Input

■

■

Good Protection Coverage With Auto Self­Recovery

o VDD Over Voltage Clamp and Under Voltage

Lockout with Hysteresis (UVLO)

o Gate Output Maximum Voltage Clamp (18V)
o On-Bright Proprietary Line Input Compensated

Cycle-by-Cycle Over-current Threshold Setting
For Constant Output Power Limiting Over
Universal Input Voltage Range.

o Overload Protection (OLP)

APPLICATIONS

Offline AC/DC flyback converter for

■

Battery Charger
Power Adaptor

■

Set-Top Box Power Supplies

■

Open-frame SMPS

■

TYPICAL APPLICATION

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OB2263

Current Mode PWM Controller

GENERAL INFORMATION

Pin Configuration

The OB2263 is offered in SOT23-6, DIP8 and SOP8
packages, shown as below.

Frequency Shuffling

Ordering Information

Part Number Description

OB2263MP SOT23-6, Pb-free
OB2263AP DIP8, Pb-free
OB2263CP SOP8, Pb-free

Package Dissipation Rating

Package

RθJA
(°C/W)

DIP8 90
SOP8 150
SOT23-6

200

Absolute Maximum Ratings

Parameter Value

VDD DC Supply Voltage 30 V
VDD Zener Clamp
Voltage

Note

VDD_Clamp+0.1V

VDD DC Clamp Current 10 mA
V

Input Voltage -0.3 to 7V

FB

V

Input Voltage to

SENSE

-0.3 to 7V
Sense Pin
VRI Input Voltage to RI Pin -0.3 to 7V
Min/Max Operating
Junction Temperature T
Min/Max Storage
Temperature T

VDD_Clamp has a nominal value of 34V.

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.

stg

-20 to 150 oC

J

-55 to 160 oC

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OB2263

Marking Information

Current Mode PWM Controller

Frequency Shuffling

TERMINAL ASSIGNMENTS

Pin Name I/O Description

GND P Ground
FB I Feedback input pin. The PWM duty cycle is determined by voltage level into this pin and

SENSE pin input.

RI I Internal Oscillator frequency setting pin. A resistor connected between RI and GND sets

the PWM frequency.
SENSE I Current sense input pin. Connected to MOSFET current sensing resistor node.
VDD P Chip DC power supply pin.
GATE O Totem-pole gate drive output for the power MOSFET.

RECOMMENDED OPERATING CONDITION

Symbol Parameter Min

Max

VDD VDD Supply Voltage 10 to 30 V
RI RI Resistor Value 100 Kohm
T

A

Operating Ambient Temperature -20 to 85

Unit

o

C

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OB2263

BLOCK DIAGRAM

Current Mode PWM Controller

Frequency Shuffling

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OB2263

Current Mode PWM Controller

Frequency Shuffling

ELECTRICAL CHARACTERISTICS

(TA = 25OC if not otherwise noted)

Symbol Parameter Test Conditions Min Typ Max Unit
Supply Voltage (VDD)

I_VDD_Startup VDD Start up

Current

I_VDD_Ops Operation Current VDD=16V,

UVLO(ON) VDD Under Voltage

Lockout Enter
UVLO(OFF) VDD Under Voltage

Lockout Exit

(Recovery)
VDD_Clamp VDD Zener Clamp

Voltage

Feedback Input Section(FB Pin)

A

VCS

V

Open V

FB_

PWM Input Gain

Open Loop

FB

Voltage
IFB_Short FB pin short circuit

current
VTH_0D Zero Duty Cycle FB

Threshold Voltage
VTH_PL Power Limiting FB

Threshold Voltage
TD_PL Power limiting

Debounce Time
ZFB_IN Input Impedance 6 Kohm
DC_MAX Maximum Duty

Cycle

Current Sense Input(Sense Pin)

T_blanking Leading edge

blanking time
Z

_IN Input Impedance 40 Kohm

SENSE

TD_OC Over Current

Detection and

Control Delay
VTH_OC Over Current

Threshold Voltage at

zero Duty Cycle

Oscillator

F

Normal Oscillation

OSC

Frequency

∆f_Temp

Frequency

Temperature Stability

∆f_VDD

Frequency Voltage

Stability
RI_range Operating RI Range 50 100 150 Kohm
V_RI_open RI open load voltage 2 V

VDD =12.5V, RI=100K

3 20 uA
Measure Leakage current
into VDD

1.4 mA

RI=100Kohm, V

FB

=3V

7.8 8.8 9.8 V

13 14 15 V

I

= 5 mA 34 V

VDD

ΔV

FB

/ΔVcs

2.0 V/V

4.8 V

Short FB pin to GND and

1.2 mA
measure current
VDD = 16V,

0.75 V
RI=100Kohm

3.7 V

35 mSec

VDD=18V,

75 %
RI=100Kohm, FB=3V,
CS=0

RI = 100 Kohm 300 ns

VDD = 16V,
CS>V

_OC, FB=3.3V

TH

75 nSec

FB=3.3V, RI=100 Kohm 0.70 0.75 0.80 V

RI = 100 Kohm 60 65 70 KHZ

VDD = 16V,
RI=100Kohm, T

o

to 100

C

VDD = 12-25V,

-20oC

A

5 %

5 %
RI=100Kohm

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OB2263

F

_BM Burst Mode Base

osc

Frequency

Current Mode PWM Controller

VDD = 16V, RI =

22 KHZ
100Kohm

Frequency Shuffling

Gate Drive Output

VOL Output Low Level VDD = 16V, Io = -20 mA 0.8 V
VOH Output High Level VDD = 16V, Io = 20 mA 10 V
V_Clamp Output Clamp

18 V

Voltage Level
T_r Output Rising Time VDD = 16V, CL = 1nf 220 nSec
T_f Output Falling Time VDD = 16V, CL = 1nf 70 nSec

Frequency Shuffling

∆f_OSC

Frequency

RI=100K -3 3 %
Modulation range
/Base frequency

f_shuffling Shuffling Frequency RI=100K 64 HZ

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OB2263

Current Mode PWM Controller

CHARACTERIZATION PLOTS

VDD = 16V, RI = 100 Kohm, TA = 25oC condition applies if not otherwise noted.

20

15

VDD Startup Current vs. Voltage

5.0

4.6

4.2

I_VDD_startup vs. Temp

10

3.8

5

3.4

Ivdd_startup(uA

0

0246810121416

I_vdd_startup (uA)

3.0

-20 10 40 70 100 130

VDD(V)

Frequency Shuffling

Temp(C)

VDD UVLO and Ops Current

VDD Operation Current vs. Load(pF)

2

50KHz 65KHz 100KHz

1.6

1.2

0.8

I(VDD) (mA)

0.4

0

0 5 10 15 20 25 30

VDD (V)

UVLO(ON) vs Temp

9.0

8.8

8.6

8.4

8.2

UVLO(ON) (V)

8.0

-20 10 40 70 100 130

Temp(C)

5
4
3
2

I(VDD) (m A)

1
0

0 500 1000 1500 2000

Gat e L o ad ( p F)

UVLO(OFF) vs Temp

14.5

14.4

14.3

14.2

UVLO(OFF) (V)

14.1

14.0

-20 10 40 70 100 130

Temp(C)

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OB2263

Fosc(KHz) vs. RI(Kohm)

140
115

90
65

Fosc(KHz)

40

50 70 90 110 130 150

RI(Kohm)

Current Mode PWM Controller

Fosc vs. Temp

66.5
66

65.5
65

64.5

Fosc (KHz)

64

63.5

-20 5 30 55 80 105 130
Temp (C)

Frequency Shuffling

Vth_OC (V) vs Duty_cycle(%)

1.2

1.1
1

0.9

Vth_OC(V

0.8

0.7

0 10203040506070

Duty_cycle(%)

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OB2263

Current Mode PWM Controller

OPERATION DESCRIPTION

The OB2263 is a highly integrated PWM controller
IC optimized for offline flyback converter
applications in sub 30W power range. 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 OB2263 is designed to be very
low so that VDD could be charged up above UVLO
threshold level and device starts up quickly. A large
value startup resistor can therefore be used to
minimize the power loss yet provides reliable
startup in application. For 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 low power
dissipation solution.

• Operating Current

The Operating current of OB2263 is low at 1.4mA.
Good efficiency is achieved with OB2263 low
operating current together with extended burst
mode control features.

• Frequency shuffling for EMI improvement

The frequency Shuffling/jittering (switching
frequency modulation) is implemented in OB2263.
The oscillation frequency is modulated with a
random source so that the tone energy is spread out.
The spread spectrum minimizes the conduction
band EMI and therefore reduces system design
challenge.

• Extended Burst Mode Operation

At zero load or light load condition, majority 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.
OB2263 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. 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

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Frequency Shuffling

minimize the switching loss and reduces the
standby power consumption to the greatest extend.
The frequency control also eliminates the audio
noise at any loading conditions.

• 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.

F

OSC

6500

=

)(

KohmRI

Khz

)(

• Current Sensing and Leading Edge Blanking

Cycle-by-Cycle current limiting is offered in
OB2263 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.

• 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.

• Gate Drive

OB2263 Gate is connected to an external MOSFET
gate 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.
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 easier to achieve with this
dedicated control scheme. An internal 18V clamp is
added for MOSFET gate protection at higher than
expected VDD input.

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OB2263

Current Mode PWM Controller

• Protection Controls

Good power supply system reliability is achieved
with its rich protection features including Cycle-by­Cycle current limiting (OCP), Over Load
Protection (OLP) and over voltage clamp, Under
Voltage Lockout on VDD (UVLO).
With On-Bright Proprietary technology, the OCP
threshold tracks PWM Duty cycles and is line
voltage compensated to achieve constant output
power limit over the universal input voltage range
with recommended reference design.

Frequency Shuffling

At overload condition when FB input voltage
exceeds power limit threshold value for more than
TD_PL, control circuit reacts to shut down the
output power MOSFET. Device restarts when VDD
voltage drops below UVLO limit.
VDD is supplied by transformer auxiliary winding
output. It is clamped when VDD is higher than
threshold value. The power MOSFET is shut down
when VDD drops below UVLO limit and device
enters power on start-up sequence thereafter.

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OB2263

PACKAGE MECHANICAL DATA

SOT23-6

Current Mode PWM Controller

Frequency Shuffling

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OB2263

8-Pin Plastic DIP

Current Mode PWM Controller

Frequency Shuffling

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