OB2560
High Precision CC/CV Primary-Side Controller
GENERAL DESCRIPTION
OB2560 is a high performance offline PSR
controller for low power AC/DC charger and
adapter applications. It operates in primary-side
sensing and regulation. Consequently,
opto-coupler and TL431 could be eliminated.
Proprietary Constant Voltage (CV) and Constant
Current (CC) control is integrated as shown in the
figure below.
In CC control, the current and output power setting
can be adjusted externally by the sense resistor
Rs at CS pin. In CV control, multi-mode operations
are utilized to achieve high performance and high
efficiency. In addition, good load regulation is
achieved by the built-in cable drop compensation.
Device operates in PFM in CC mode at large load
condition and it operates in PWM with frequency
reduction at light/medium load. The chip
consumes very low operation current. It achieves
less than 100mW standby power to meet strict
standby power standard.
OB2560 offers comprehensive protection
coverage with auto-recovery feature including
Cycle-by-Cycle current limiting, VDD over voltage
protection, feedback loop open protection, short
circuit protection, built-in leading edge blanking,
VDD under voltage lockout (UVLO), OTP etc.
OB2560 is offered in SOT23-6 package.
FEATURES
Driving MOSFET
Primary-side sensing and regulation without
TL431 and opto-coupler
High precision constant voltage and current
regulation at universal AC input
Multi-mode PWM/PFM operation for efficiency
improving
Good dynamic response
Programmable CV and CC regulation
Built-in primary winding inductance
compensation
Programmable cable drop compensation
No need for control loop compensation
Audio noise free operation
Built-in leading edge blanking (LEB)
Ultra low start-up current (typ. 1uA) and low
operating current (typ. 650uA)
Comprehensive protection coverage with
auto-recovery
Precise external OTP
VDD over voltage protection
VDD under voltage lockout with
hysteresis (UVLO)
Cycle-by-Cycle current limiting
Feedback loop open protection
Output short circuit protection
APPLICATIONS
Low Power AC/DC offline SMPS for
Cell Phone Charger
Digital Cameras Charger
Small Power Adapter
Auxiliary Power for PC, TV etc.
Linear Regulator/RCC Replacement
Figure.1. Typical CC/CV Curve
TYPICAL APPLICATION
~ ++
AC
VO
NS + CO
NP
FB VDD
GND GATE
RT CS
OB2560
+
NAUX
RS
©On-Bright Electronics
Confidential
-1-
Preliminary datasheet
OB_DOC_DS_256000
