High Performance CCM/QR mode Primary-Side Controller
OB2374
GENERAL DESCRIPTION
OB2374 is an excellent primary side regulation
controller with CC/CV operation for medium level
power AC/DC charger and adapter applications.
The device directly drives a power MOSFET and
operates in CCM/QR mode to provide high
efficiency along with several functions of built-in
protections. It removes the need for secondary
feedback circuitry to lower the total bill of material
cost. Proprietary Constant Voltage (CV) and
Constant Current (CC) control is integrated as
shown in the figure below.
In CV control, the controller changes the mode of
operation according to line voltage and load
condition. At full loading, the controller operates in
fixed frequency CCM in low line voltage and
operates quasi-resonant (QR) mode in high line
voltage. The primary side regulation power
supplies up to high power without the efficiency
limitation of DCM or audible noise.
In CC control, OB2374 samples the Vcs peak
current and the demagnetization pulse to
regulation the output constant current. The current
and output power setting can be adjusted
externally by the sense resistor Rs at CS pin.
OB2374
offers
comprehensive
protection
coverage with auto-recovery feature including
Cycle-by-Cycle current limiting, VDD OVP, OLP,
SCP etc.
OB2374 consumes less than 75mW input power at
no- load condition with high line voltage.
OB2374 is offered in SOT23-6 package.
FEATURES
Primary-side sensing and regulation operates
in CCM/QR mode without TL431 and
opto-coupler
High precision constant voltage and current
regulation at universal AC input
Fixed frequency (65kHz) CCM mode
operation with low line voltage at full load
Quasi-resonant operation for high efficiency in
high line voltage
Good dynamic response
Programmable CV and CC regulation
Built-in primary winding inductance
compensation
Programmable cable drop compensation
Built-in control loop compensation
External over temperature protection with
latch shutdown (OTP)
Audio noise free operation
Built-in leading edge blanking (LEB)
Ultra low start-up current and low operating
current
Comprehensive protection coverage with
auto-recovery
VDD over voltage protection (OVP)
VDD under voltage lockout with
hysteresis (UVLO)
Cycle-by-cycle current limiting
Feedback open loop protection (OLP)
Output short circuit protection (SCP)
APPLICATIONS
Medium level Power AC/DC offline SMPS for
Cell phone charger
Tablet PC
AC/DC adapter
Set-top box power supplies
Figure.1. Typical CC/CV Curve
©On-Bright Electronics
Confidential
-1-
Preliminary Datasheet
OB_DOC_DS_237400
High Performance CCM/QR mode Primary-Side Controller
OB2374
TYPICAL APPLICATION
GENERAL INFORMATION
Pin Configuration
The pin map is shown as below for SOT23-6.
Absolute Maximum Ratings
Parameter
Value
VDD Voltage
-0.3 to 30V
FB Input Voltage
-0.3 to 7V
COMPInput Voltage
-0.3 to 7V
CS Input Voltage
-0.3 to 7V
GATE Input Voltage
-0.3 to 24V
Min/Max Operating Junction
-40 to 150
℃
Temperature T
J
Operating
Ambient
-20 to 85
℃
Temperature T
A
Min/Max
Storage
-55 to 150
℃
Temperature T
stg
Lead
Temperature
260
℃
(Soldering, 10secs)
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.
FB
GND
VDD
1
2
3
6
5
4
COMP
CS
GATE
Ordering Information
Part Number
Description
OB2374MP
SOT23-6, Pb-free in T&R
Package Dissipation Rating
Package
RθJA (℃/W)
SOT23-6
200
Recommended Operating Condition
Symbol
Parameter
Range
VDD
VDD Supply Voltage
9 to 22V
©On-Bright Electronics
Confidential
-2-
Preliminary Datasheet
OB_DOC_DS_237400
嵌入式系统
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