OB3622M (On-Bright)
High Precision Non-isolated Power Switch

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OB3622M
High Precision Non-isolated Power Switch
GENERAL DESCRIPTION
OB3622M is a high current precision, non-isolated
power switch for LED lighting. It works under
transition mode.
It significantly simplifies the LED lighting system
design by eliminating the auxiliary winding
inductance and works under low current. A 650V
power switch is also integrated into the device.
The LED current can be adjusted externally by the
sense resistor Rs at CS pin and high precision
constant current regulation is realized.
OB3622M offers comprehensive protection
coverage with auto-recovery features including
LED string open protection, LED string short circuit
protection, cycle-by-cycle current limiting, built-in
leading edge blanking, VDD under voltage lockout
(UVLO), over temperature protection (OTP), etc.
OB3622M is offered in SOP8 package.
FEATURES
High precision Constant Current Regulation at
Universal AC input
Sense and supply without auxiliary winding
inductance
Low System Cost and High Efficiency
Low operation current
Programmable CC Regulation
Transition Mode operation
Built-in Primary winding inductance
compensation
LED string short circuit protection
LED string open protection
Cycle-by-Cycle Current Limiting
Built-in Leading Edge Blanking (LEB)
VDD Under Voltage Lockout with Hysteresis
Over temperature protection (OTP)
APPLICATIONS
LED lighting
TYPICAL APPLICATION
~+
AC
+
CS
NC
VDD
SW
GND
GND
Drain
Drain
OB3622M
Output Power Table
Product
Condition
90Vac~264Vac Input
220Vac±20% Input
OB3622M
IOUT0.2A
6.6W
11.3W
Note: Maximum practical continuous power in an open frame design with sufficient drain pattern as a heat sink, at 50ambient
and 60temperature rise. Higher output power is possible with extra added heat sink or air circulation to reduce thermal resistance.
©On-Bright Electronics
Confidential
-1-
Preliminary Datasheet
OB_DOC_DS_3622M00


OB3622M (On-Bright)
High Precision Non-isolated Power Switch

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OB3622M
High Precision Non-isolated Power Switch
GENERAL INFORMATION
Pin Configuration
The pin map is shown as below for SOP8.
CS 1
8 GND
NC 2
7 GND
VDD 3
6 Drain
SW 4
5 Drain
Ordering Information
Part Number
Description
OB3622MCP-H 8 Pin SOP, Pb free in Tube
OB3622MCPA-H 8 Pin SOP, Pb free in T&R
Note: All Devices are offered in Pb-free Package if not
otherwise noted.
Package Dissipation Rating
Package
RθJA (/W)
SOP8
90
.
Absolute Maximum Ratings
Parameter
Value
VDD Voltage
-0.3 to 20V
DRAIN Voltage
-0.3 to 650V
CS Input Voltage
-0.3 to 7V
SW Input Voltage
-0.3 to 20V
Min/Max Operating
Junction Temperature TJ
Min/Max Storage
Temperature Tstg
Lead Temperature
(Soldering, 10secs)
-40 to 150
-55 to 150
260
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.
OB3622M X X
X -X
High PF, High CC Buck Topology LED driver
Package Package Pb free Packing BVdss
C:SOP8
P:Pb-free
Blank:Tube H: 650V
A: Tape/Reel
©On-Bright Electronics
Confidential
-2-
Preliminary Datasheet
OB_DOC_DS_3622M00


OB3622M (On-Bright)
High Precision Non-isolated Power Switch

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Marking Information
OB3622M
High Precision Non-isolated Power Switch
TERMINAL ASSIGNMENTS
Pin Num Pin Name I/O Description
1 CS I Current sensing terminal
2 NC
No Connection
3
VDD
P Power supply Input
4 SW I MOSFET Source Terminal
5,6
DRAIN
I MOSFET Drain Terminal
7
GND
P Power Ground, suggest to be left floating with no pad in PCB layout.
8
GND
P Power Ground
©On-Bright Electronics
Confidential
-3-
Preliminary Datasheet
OB_DOC_DS_3622M00


OB3622M (On-Bright)
High Precision Non-isolated Power Switch

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BLOCK DIAGRAM
OB3622M
High Precision Non-isolated Power Switch
VDD 3
GND 7,8
5,6 Drain
UVLO
LDO
POR
AVDD
600V
CC
Controller
Logic
Control
4 SW
Line
compensation
OTP
OCP
LEB 1 CS
©On-Bright Electronics
Confidential
-4-
Preliminary Datasheet
OB_DOC_DS_3622M00


OB3622M (On-Bright)
High Precision Non-isolated Power Switch

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OB3622M
High Precision Non-isolated Power Switch
ELECTRICAL CHARACTERISTICS
(TA = 25, VDD=7.5V, if not otherwise noted)
Symbol
Parameter
Test Conditions
Min Typ
Supply Voltage (VDD) Section
I start-up
Start up current
VDD=UVLO(OFF)-1V
120
I oper
operation current
VDD=7.5V, no loading
280
UVLO(OFF) VDD under voltage lockout exit
9
UVLO(ON)
VDD under voltage lockout enter
6.5
VDD_CLAMP VDD CLAMP
VDD current 1mA
10.5
Current Sense Input Section
TLEB
LEB time
0.3
Vth_ocp
Over current threshold
485 500
Td_oc
OCP propagation delay
From OCP comparator
to gate drive
100
Toff_max
Maximum off time
600
Toff_min
Minimum off time
5
Ton_max
Maximum on time
305
Source Drive Section
Rdson_l
Source drive low side on resistor
1.3
OTP Section
OTP
Over temperature protection
150
Power MOSFET Section
BVdss
MOSFET
Drain-Source
Breakdown Voltage
650
Rds,on
On resistance
18
Max Unit
150 uA
320 uA
V
V
V
us
515 mV
ns
us
us
us
ohm
V
ohm
©On-Bright Electronics
Confidential
-5-
Preliminary Datasheet
OB_DOC_DS_3622M00


OB3622M (On-Bright)
High Precision Non-isolated Power Switch

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OB3622M
High Precision Non-isolated Power Switch
CHARACTERIZATION PLOTS
UVLO(ON) vs Temperature
7.5
7.1
6.7
6.3
5.9
5.5
-40 -10 20 50 80 110 140
Tem perature()
UVLO(OFF) vs Temperature
10.0
9.6
9.2
8.8
8.4
8.0
-40 -10 20 50 80 110 140
Tem perature()
I_startup vs Temperature
105
101
97
93
89
85
-40 -10 20 50 80 110 140
Tem perature()
I_oper vs Temperature
300
280
260
240
220
200
-40 -10 20 50 80 110 140
Tem perature()
Vth_oc vs Temperature
550
530
510
490
470
450
-40 -10 20 50 80 110 140
Tem perature()
Rds_on(ohm )vs Tem perature
34
29
24
19
14
9
-40 -10 20 50 80 110 140
Temperature()
Ivdd vs VDD
300
250 Ivdd_off
200 Ivdd_on
150
100
50
0
0 1 2 3 4 5 6 7 8 9 10
VDD(V)
©On-Bright Electronics
Confidential
-6-
Preliminary Datasheet
OB_DOC_DS_3622M00


OB3622M (On-Bright)
High Precision Non-isolated Power Switch

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OB3622M
High Precision Non-isolated Power Switch
OPERATION DESCRIPTION
OB3622M is a high current precision, non-isolated
power switch for LED lighting working under
transition mode. It significantly simplifies the LED
lighting system design by eliminating the auxiliary
winding inductance and works under low current. A
650V power switch is also integrated into the
device.
Start up Control
Startup process is realized by charging VDD
capacitor. When VDD voltage reaches up to
UVLO(OFF), the inner circuit works. A 10.5V
(typical) clamp circuit is applied to clamp VDD
voltage. At work state, no auxiliary winding
inductance is necessary.
Principle of CC Operation
For buck type operating in transition mode, the
peak voltage of CS is detected cycle-by-cycle, and
compared with internal reference voltage, Vth_ocp
(typical value 500mV).. When the voltage at CS
pin is up to the threshold voltage, the power switch
will be turned off.
Ipk Vth _ ocp
(1)
RCS
Where, Rcs indicates the resistor at CS pin for
primary side current sensing.
Refer to the equation 1, LED output current is
ILED I pk Vth _ ocp
(2)
2 2 RCS
OB3622M works under transition mode and the
on-time for power switch is
ton LIpk
(3)
Vin VLED
Where L is the inductor of transformer at
primary-side winding, Vin is line voltage after
rectifying and VLED is the voltage at LED.
When power switch turns off, the current flowing in
the inductor will reduce to zero and the power
switch will turn on after then. The off-time for
power switch is
toff LIpk
VLED
The inductor could also be calculated by
(4)
L VLEDVinVLED
f Ipk Vin
(5)
Where, f is the working frequency. The working
frequency changes with input voltage. The lowest
input voltage determines the lowest working
frequency and the highest input voltage
determines the highest working frequency.
The minimum and maximum off-time are set in
OB3622N. Therefore, the value of inductor should
be carefully designed to achieve good LED output
current, according to equation 4.
Inner Line Compensation
OB3622N provides internal line compensation,
therefore no outside sensing devices are needed.
The compensated voltage is added to CS voltage
cycle-by-cycle and LED output current is kept
constant under different line voltage.
Current Sensing and Leading Edge
Blanking
Cycle-by-Cycle current limiting is offered in
OB3622M. The switch current is detected by a
sense resistor into the CS pin. An internal leading
edge blanking circuit chops off the sensed voltage
spike at initial power MOSFET on state so that the
external RC filtering on sense input is no longer
needed.
Protection
OB3622M offers comprehensive protection
coverage with auto-recovery features including
LED string open loop protection, LED string short
circuit protection.
OB3622M detects the states of LED. When LED
string short circuit occurs, the switching frequency
is reduced to the minimum switching frequency
with maximum Toff time. OB3362M resumes
normal operation after the fault condition is
removed. When LED string open circuit occurs,
OB3622M stops switching and re-detect the LED
string status after 160ms (typical). If the fault
condition is removed, OB3362M resumes normal
operation. Otherwise, the above operation is
repeated.
Over temperature protection is offered in
OB3622M. When temperature rises above 150
(typical), switching will be stopped. The normal
operation is resumed until the temperature falls
below 130(typical).
©On-Bright Electronics
Confidential
-7-
Preliminary Datasheet
OB_DOC_DS_3622M00


OB3622M (On-Bright)
High Precision Non-isolated Power Switch

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PACKAGE MECHANICAL DATA
OB3622M
High Precision Non-isolated Power Switch
Symbol
A
A1
A2
b
c
D
E
E1
e
L
θ
Dimensions In Millimeters
Min Max
1.350
1.750
0.050
0.250
1.250
1.650
0.310
0.510
0.100
0.250
4.700
5.150
3.800
4.000
5.800
6.200
1.270 (BSC)
0.400
1.270
0º 8º
Dimensions In Inches
Min Max
0.053
0.069
0.002
0.010
0.049
0.065
0.012
0.020
0.004
0.010
0.185
0.203
0.150
0.157
0.228
0.244
0.050 (BSC)
0.016
0.050
0º 8º
©On-Bright Electronics
Confidential
-8-
Preliminary Datasheet
OB_DOC_DS_3622M00


OB3622M (On-Bright)
High Precision Non-isolated Power Switch

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OB3622M
High Precision Non-isolated Power Switch
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
-9-
Preliminary Datasheet
OB_DOC_DS_3622M00




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