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BP2866XJ
晶丰明源半导体
Non-isolated Buck Offline LED Driver
Description
Features
BP2866XJ is a high precision Buck constant current
LED driver. The device operates in critical conduction
mode and is suitable for 85Vac~265Vac universal
input offline LED lighting.
The BP2866XJ integrates a 500V power MOSFET,
with proprietary MOSFET driving technique. It
doesn’t need VCC capacitor and startup resistor. It can
achieve excellent constant current performance with
very few external components, so the system cost and
size are minimized.
BP2866XJ operates in critical conduction mode, it can
achieve precise output current and excellent line
regulation. The driver output current does not change
with the inductance and output voltage.
No VCC Capacitor and Startup Resistor
Integrated HV JFET for IC Power Supply
Internal 500V Power MOSFET
Critical Conduction Mode Operation
±5% LED Output Current Accuracy
Configurable OVP by Rovp resistor
LED Short Protection
Thermal Regulation Function
Available in SOP7 Package
Applications
LED Bulb
LED Tube
Other LED Lighting
The BP2866XJ offers protections to improve the
system reliability, including LED short circuit
protection, and thermal regulation function.
Typical Application
AC
BP2866XJ
HV 4
5 DRAIN
NC 3
6 DRAIN
ROVP 2
7 CS
GND 1
Figure 1. Typical application circuit for BP2866XJ
BP2866XJ_EN _DS_Rev.1.0
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BP2866XJ
晶丰明源半导体
Non-isolated Buck Offline LED Driver
Naming rules
BP286
6
Package type
Series name
XJ
TypitalRdson
Ordering Information
Part Number
Package
Operating
Temperature
BP2866XJ
SOP7
-40 ℃ to 105 ℃
Packing Method
Marking
Tape
BP2866X
XXXXXXY
WXXXYYJ
4000Pcs/Reel
Pin Configuration and Marking Information
XXXXXXY: Lot Code
WXXX: Sign
YY: Week
CS
GND
NC
HV
BP2866X
XXXXXXY
WXXXYYJ
ROVP
DRAIN
DRAIN
Figure 2. Pin configuration
Pin Definition
Pin No.
Name
1
GND
Ground
2
Rovp
OVP configure by a resistor between this pin and GND Pin
3
NC
Not connect
4
HV
High voltage power supply Pin
5,6
DRAIN
7
CS
BP2866XJ_EN _DS_Rev.1.0
Description
Internal HV Power MOSFET Drain.
Current Sense Pin. Connect a sense resistor between this pin and GND pin.
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BP2866XJ
晶丰明源半导体
Non-isolated Buck Offline LED Driver
Absolute Maximum Ratings (note1)
Symbol
HV
DRAIN
CS
Parameters
Range
Units
500V High voltage supply Pin
-0.3~500
V
Internal HV MOSFET drain voltage
-0.3~500
V
-0.3~8
V
-0.3~8
V
Current sense pin input voltage
Rovp
A
B
C
D
F
G
500
650
900
1000
1100
1500
IDMAX
Maximum drain current @ TJ=100℃
PDMAX
Power dissipation (note 2)
0.45
W
θJA
Thermal resistance (Junction to
Ambient)
145
℃/W
TJ
Operating junction temperature
-40 to 150
℃
Storage temperature range
-55 to 150
℃
2
KV
TSTG
ESD (note 3)
mA
Note 1: Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. Under “recommended operating
conditions” the device operation is assured, but some particular parameter may not be achieved. The electrical characteristics table defines the operation
range of the device, the electrical characteristics is assured on DC and AC voltage by test program. For the parameters without minimum and maximum value
in the EC table, the typical value defines the operation range, the accuracy is not guaranteed by spec.
Note 2: The maximum power dissipation decrease if temperature rise, it is decided by TJMAX, θJA, and environment temperature (TA). The maximum power
dissipation is the lower one between PDMAX = (TJMAX - TA)/ θJA and the number listed in the maximum table.
Note 3: Human Body mode, 100pF capacitor discharge on 1.5KΩ resistor
Recommended Operation Conditions
Symbol
Parameter
Range
ILED
Output LED current @
Vout=72V
(Input voltage 176V～265V)
ILED max
Unit
Maximum Output LED current
BP2866XJ_EN _DS_Rev.1.0
C
D
F
G
160
220
250
280
350
380
B
C
D
F
G
240
Minimum LED Loading Voltage
B
A
VLED min
A
300
400
450
500
550
mA
mA
& gt; 20
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& gt; 15
V
3
BP2866XJ
晶丰明源半导体
Non-isolated Buck Offline LED Driver
Electrical Characteristics (Notes 4, 5) (Unless otherwise specified, TA =25 ℃)
Symbol
Parameter
Conditions
Operating current
Min
FOP=4kHz
Typ
Max
Units
Supply Voltage Section
ICC
230
uA
Current Sense Section
VCS_TH
Threshold Voltage for
Peak Current Limit
TLEB
Leading Edge Blanking
Time for Current Sense
500
ns
TDELAY
Switch Off Delay Time
200
ns
VEN
OVP Pin enable threshold
0.3
V
IOVP
OVP Pin output current
35
uA
362
373
384
mV
Rovp
Internal Time Control Section
TOFF_MIN
Minimum OFF Time
2.5
us
TOFF_MAX
Maximum OFF Time
250
us
TON_MAX
Maximum On Time
40
us
TOVP_RST
OVP reset time
8
ms
MOSFET Section
BVDSS
Drain-Source Breakdown
Voltage
VGS=0V/IDS=250uA
IDSS
Power MOSFET leakage
current
VGS=0V/
VGS=500V
500
V
1
AJ RDS_ON
15
BJ RDS_ON
uA
8.5
CJ RDS_ON
DJ RDS_ON
MOSFET conductor
resistance
VGS=10V/IDS=0.1A
5.8
4.8
FJ RDS_ON
3
GJ RDS_ON
Ω
2
Thermal Regulation Section
TREG
Thermal Regulation
Temperature
140
℃
Note 4: production testing of the chip is performed at 25°C.
Note 5: the maximum and minimum parameters specified are guaranteed by test, the typical value are guaranteed by design, characterization and statistical
analysis
BP2866XJ_EN _DS_Rev.1.0
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BP2866XJ
晶丰明源半导体
Non-isolated Buck Offline LED Driver
Internal Block Diagram
DRAIN
HV
VCC Power supply
VCC
UVLO & Power on
reset
ROVP
Thermal
Reculation
OVP
control
Logic &
Protection
ZCD
LEB
+
Current
sense
-
0.373V
GND
CS
Figure 3. BP2866XJ Internal Block Diagram
Application Information
The BP2866XJ is a high performance non-isolated
Buck converter specially designed for LED lighting.
The device integrates a 500V power MOSFET. With
very few external components, the converter achieves
excellent constant current control. And it can save
VCC capacitor and startup resistor. So the system size
and cost is greatly reduced.
Start Up
When the system powered on, the HV pin supply
the power to the IC. Then the IC start working. After
the chip operates normally, the HV JFET supplies the
working current also.
Constant Current Control
Cycle by Cycle current sense is adopted in BP2866XJ,
the CS pin is connected to the internal current sense
comparator, and the voltage on CS pin is compared
with the internal 0.373V reference voltage. The
MOSFET will be switched off when the voltage on
CS pin reaches the threshold. The CS comparator
includes a 500ns leading edge blanking time.
The peak inductor current is given by:
I PK
373
R CS
Where, RCS is the current sense resistor value.
BP2866XJ_EN _DS_Rev.1.0
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BP2866XJ
晶丰明源半导体
Non-isolated Buck Offline LED Driver
The current in LED can be given by:
I LED
system will operate in discontinuous current mode
and the output current will be lower than the designed
value. If the inductance is too large, the Toff may be
higher than the maximum off time, the system will
operate in continuous conduction mode and the output
current will be higher than the designed value. So it is
important to choose a proper inductance.
I PK
2
Where, IPK is the peak current of the inductor.
Inductor Selection
The BP2866XJ works under inductor current critical
conduction mode. When the power MOFET is
switched on, the current in the inductor rises up from
zero, the on time of the MOSFET is given by:
t on
L IPK
VIN VLED
The OVP voltage is set by the resistor which connects
the ROVP Pin. The current out of the ROVP Pin is
35uA.
When the LED load is open, the output voltage
becomes higher and the Toff becomes lower. So we
can get the Tovp by the needed OVP voltage. The
Tovp is given by:
Where,
L is the inductor value
VIN is the DC bus voltage after the rectifier bridge
VLED is the voltage on the LED
Tovp
After the power MOSFET is switched off, the current
in the inductor decreases. When the inductor current
reaches zero, the power MOSFET is turned on again
by IC internal logic. The off time of the MOSFET is
given by:
t off
Rovp Resistor Value calculate
L IPK
VLED
where，
Vcs is CS reference voltage（373mV）
Vovp is the needed OVP
Then we can get the Rovp resistor value by the Tovp.
The Rovp is given by:
Rovp
The inductance can be given by:
L
VLED (VIN VLED )
f IPK VIN
The f is the system switching frequency, which is
proportional to the input voltage. So the minimum
switching frequency is set at lowest input voltage, and
the maximum switching frequency is set at highest
input voltage.
The minimum and maximum off time of BP2866XJ
are 2.5us and 250us, respectively. Referring to the
equation of Toff calculation, if the inductance is too
low, the Toff may be lower than the minimum off time,
BP2866XJ_EN _DS_Rev.1.0
L Vcs
Rcs Vovp
150
10 3
Tovp
Noted: the Rovp Pin has the enable function. When
the ROVP Pin voltage is lower 0.3V, the IC is disabled
and the system has no output. So we suggest the
ROVP resistor will be higher 15kΩ. If you needn’t
OVP function you can disconnect the ROVP Pin.
Protection Function
The BP2866XJ offers rich protection functions to
improve the system reliability, including LED short
protection, thermal regulation.
When the LED short circuit is detected, the system
works at low frequency (4kHz), so the system power
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BP2866XJ
晶丰明源半导体
Non-isolated Buck Offline LED Driver
consumption is very low.
The BP2866XJ integrates thermal regulation function.
When the system is over temperature, the output
current is gradually reduced, so the output power
dissipation and thermal are also reduced. The system
temperature is regulated and the system reliability is
improved. The thermal regulation temperature is set
to 140℃ internally.
PCB Layout
The PCB designing rules should be followed in
BP2866XJ PCB layout:
CS resistor
The current sense resistor should be short to the bus
capacitor ground. And it is separated from other signal
ground. Another the bigger copper area of the CS Pin
is better for thermal dissipation.
HV Pin
HV trace should be far away from the CS pin trace
and other low voltage pin.
The Area of Power Loop
The area of main current loop should be as small as
possible to reduce EMI radiation, such as the inductor,
the power MOSFET, the output diode and the bus
capacitor loop.
Drain Pin
To increase the copper area of DRAIN pin for better
thermal dissipation. However too large copper area
may compromise EMI performance.
BP2866XJ_EN _DS_Rev.1.0
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BP2866XJ
晶丰明源半导体
Non-isolated Buck Offline LED Driver
Physical Dimensions
BP2866XJ_EN _DS_Rev.1.0
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