High Precision CC/CV Primary-Side Controller
OB2305
GENERAL DESCRIPTION
OB2305 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 30mW standby power to meet strict
standby power standard.
OB2305
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.
OB2305 is offered in SOT23-6 package (for up to
10W application) and SOP8 package (for up to
15W application).
FEATURES
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
Less than 30mW standby power consumption
at 230V with typical application circuit
Programmable CV and CC regulation
Built-in dynamic signal detection from 2
nd
-side
synchronous rectification
Built-in line voltage and primary winding
inductance compensation
Programmable cable drop compensation
No need for control loop compensation
Precise internal over temperature protection
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
VDD under voltage lockout with
hysteresis (UVLO)
Cycle-by-cycle current limiting
Feedback loop open protection
Output short circuit protection
Over temperature protection (OTP)
nf
co
TYPICAL APPLICATION
O
n-
©On-Bright Electronics
br
Figure.1. Typical CC/CV Curve
ig
ht
id
Confidential
-1-
en
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
tia
lt
o
福
Preliminary datasheet
OB_DOC_DS_230500
½
High Precision CC/CV Primary-Side Controller
OB2305
GENERAL INFORMATION
Pin Configuration
The pin map is shown as below:
SOT23-6
Ordering Information
Part Number
Description
OB2305MP
SOT23-6, Pb-free, T&R
OB2305CP
SOP8, Pb-free in Tube
OB2305CPA
SOP8, Pb-free in T&R
Package Dissipation Rating
Package
RθJA (℃/W)
SOT23-6
200
SOP8
150
SOP8
GATE
1
8
VDD
NC
2
7
GND
SD
3
6
CS
4
co
5
nf
GND
FB
br
ig
ht
O
n-
OB2305
id
Absolute Maximum Ratings
Parameter
Value
VDD Voltage
-0.3 to 30V
FB Input Voltage
-0.3 to 7V
CS Input Voltage
-0.3 to 7V
SD Input Voltage
-0.3 to 24V
GATE Input Voltage
-0.3 to 24V
Min/Max Operating Junction
-40 to 150
℃
Temperature T
J
Operating
Ambient
-40 to 150
℃
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.
en
X
X
Package
M:SOT23-6
Recommended operating condition
Symbol
Parameter
Range
VDD
VDD Supply Voltage
9 to24V
High Precision CC/CV Primary-Side PWM
Controller
C:SOP8
©On-Bright Electronics
Confidential
-2-
tia
lt
X
Package Pb-free
P:Pb-free
o
福
Packing
Blank:Tube
A: Tape/Reel
Preliminary datasheet
OB_DOC_DS_230500
½
High Precision CC/CV Primary-Side Controller
OB2305
ELECTRICAL CHARACTERISTICS
(TA = 25℃, VDD=15V, if not otherwise noted)
Symbol
Parameter
Supply Voltage (VDD) Section
I start-up
Start up current
I static
Static current
13.8
7.0
26
Test Conditions
VDD=UVLO_OFF-1V
Min
Typ. Max
5
15
Unit
uA
mA
V
V
V
V
ns
ns
mV
mV
mV
us
ns
0.65 1.0
O
UVLO(OFF)
VDD under voltage lockout exit
UVLO(ON)
VDD under voltage lockout enter
VDD_OVP
VDD over voltage protection
Max. Operating
Voltage
Current Sense Input Section
TLEB
LEB time
TD_OC
OCP propagation delay
Vth_ocp_min
Minimum over current threshold
Vth_ocp_max
Maximum over current threshold
Vcs_mini
Minimum CS threshold
Ton_max
Maximum Ton
Td_oc
OCP propagation delay
FB Input Section
Reference voltage for feedback
Vref_fb
threshold
Tpause_min
Minimum Toff
F_min
Minimum frequency
Vth_cc_shutdown CC mode shut down threshold
Maximum cable compensation
Icomp_cable
current
Gate Drive Section
V_clamp
Output clamp voltage level
Tr
Output rising time
CL=0.22nF
Tf
Output falling time
CL=0.22nF
Rdson_l
Internal switch on resistor
Before startup, SD pin leakage
Isw_leak
Vsw=VDD-1V
current
Output Over Voltage Protection
V_OVP
Output Over voltage threshold
On chip Over temperature Section
福
485
330
100
500
550
100
50
100
tia
lt
22
12
2.9
150
115
o
en
id
2.475 2.50 2.525 V
2.0
200
1.55
24
26
us
Hz
V
uA
V
ns
ns
Ω
uA
V
℃
℃
ht
co
nf
br
13.5 15
180
30
1.0 2
1
3.0
165
130
3.1
180
145
n-
T_otp
T_otp_rec
©On-Bright Electronics
ig
Over temperature trigger point
Over temperature recovery point
Confidential
-5-
Preliminary datasheet
OB_DOC_DS_230500
½
24
515
14.8 15.8
7.6 8.2
27
28
测评中心专版
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
