Datasheet

UNISONIC TECHNOLOGIES CO., LTD
UPSRB01A
Preliminary
LINEAR INTEGRATED CIRCUIT
HIGH PRECISION CC/CV
PRIMARY SIDE SWITCHING
REGULATOR

6
DESCRIPTION
5
The UTC UPSRB01A is a primary control unit for switch mode
charger and adapter applications. The controlled variable is
transferred by an auxiliary winding from the secondary to the
primary side. The device uses Pulse Frequency Modulation
(PFM) method to build discontinuous conduction mode (DCM)
flyback power supplies.
The UTC UPSRB01A operates in primary-side sensing and
regulation. Opto-coupler and TL431 could be eliminated. It also
eliminates the need of loop compensation circuitry while
maintaining stability.
The UTC UPSRB01A achieves high precision CV/CC
regulation and high power efficiency. It offers comprehensive
protection coverage with auto-recovery features including
Cycle-by-cycle current limiting, output over voltage protection,
VDD over voltage protection, feedback loop open protection, short
circuit protection, leading edge blanking, VDD under voltage
lockout, etc.

1
2
3
SOT-26
FEATURES
* ±5% constant voltage regulation at universal AC input
* Primary side control without TL431 and opto-coupler
* High precision constant current regulation at universal AC input
* Programmable CV and CC regulation
* Eliminates control loop compensation circuitry
* Flyback topology in DCM operation
* Random frequency modulation to reduce system EMI
* Driver BJT switch

4
* Built-in leading edge blanking
* Built-in primary winding inductance
compensation
* Open circuit protection
* Output over voltage protection
* VDD over voltage protection
* Short circuit protection
* Over temperature protection
ORDERING INFORMATION
Ordering Number
UPSRB01AG-AG6-R
Package
SOT-26
Packing
Tape Reel
UPSRB01AG-AG6-R
(1)Packing Type
(1) R: Tape Reel
(2)Package Type
(2) AG6: SOT-26
(3)Green Package
(3) G: Halogen Free and Lead Freee
www.unisonic.com.tw
Copyright © 2015 Unisonic Technologies Co., Ltd
1 of 7
QW-R103-095.a
UPSRB01A
Preliminary

MARKING

PIN CONFIGURATION

PIN DESCRIPTION
PIN NO.
1
2
3
4
5
6

PIN NAME
GND
CS
BASE
FB
VC
VDD
LINEAR INTEGRATED CIRCUIT
DESCRIPTION
Ground
Current sense input.
Base drive for power BJT.
The voltage feedback from the auxiliary winding
Low pass filter capacitor for cable compensation
Power supply
BLOCK DIAGRAM
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
2 of 7
QW-R103-095.a
UPSRB01A

Preliminary
LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIMUM RATING
PARAMETER
SYMBOL
RATINGS
UNIT
VDD Voltage
VDD
-0.3~30
V
VC Voltage
VC
-0.3~7
V
BASE Voltage
VBASE
-0.3~7
V
CS Input Voltage
VCS
-0.3~7
V
FB Input Voltage
VFB
-0.3~7
V
Junction Temperature
TJ
-40~150
°C
Operating Temperature
TOPR
+150
°C
Storage Temperature
TSTG
-55~150
°C
Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.

ELECTRICAL CHARACTERISTICS (TA=25°C, VDD=15V, if not otherwise noted)
PARAMETER
Supply Voltage (VDD) Section
Start up Current
Static Current
Turn-off Threshold Voltage
Turn-on Threshold Voltage
VDD Over Voltage Protection
Operating Voltage
Current Sense Input Section
LEB Time
Over Current Threshold
OCP Propagation Delay
FB Input Section
Reference Voltage for Feedback
Threshold
Minimum Pause
Maximum Pause
BASE Drive Section
Base Sourcing Maximum Current
Base Sourcing Current After Pre-off
Base Drive Low Side On Resistor
SYMBOL
MIN
TYP
MAX
UNIT
VTH(OFF)
VTH (ON)
VDD_OVP
6.0
11.5
25
1
300
6.8
12.5
27
3
400
7.6
13.5
29
25
μA
μA
V
V
V
V
TLEB
VCS
485
0.5
500
515
μS
mV
IST
IOP
TD_OC
TEST CONDITIONS
VDD=11V
VDD=15V
From OCP Comparator to
Base Drive
nS
VFB
1.98
2.00
2.02
V
TPAUSE_MIN
TPAUSE_MAX
8
2.0
10
12
μS
mS
IOUT(SOURCE)
IOUT(PRE)
RDSON_L
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
100
20
0.5
30
1
1
40
1.5
mA
mA
Ω
3 of 7
QW-R103-095.a
UPSRB01A

Preliminary
LINEAR INTEGRATED CIRCUIT
OPERATION DESCRIPTION
The UTC UPSRB01A is a primary control unit for switch mode charger and adapter applications. It operates in
primary-side sensing and regulation. Opto-coupler and TL431 could be eliminated. Proprietary built-in CV and CC
control can achieve high precision CV/CC performance. It uses Pulse Frequency Modulation (PFM) method to build
discontinuous conduction mode (DCM) flyback power supplies.
Startup control
The VDD pin of UTC UPSRB01A is connected to the line input through a resistor. A large value startup resistor can
be used to minimize the power loss in application because the start current of UTC UPSRB01A is very low. When
the VDD voltage reaches VTH (ON), the internal startup circuit is disabled and the IC turns on.
Operating Current
The Operating current of UTC UPSRB01A is as low as 400μA. Good efficiency and very low standby power can
be achieved.
Constant Voltage Operation
The output voltage is defined by the transmission ratio between the secondary and auxiliary winding. The UTC
UPSRB01A captures the auxiliary winding feedback voltage at FB pin and operates in constant-voltage (CV) mode
to regulate the output voltage. The auxiliary voltage reflects the output voltage is given by:
N
VAUX = A ×(VO + ∆V)
(1)
NS
Where △V indicates the drop voltage of the output diode.
Figure2. Auxiliary voltage waveform
Via a resistor divider connected between the auxiliary winding and FB, the VAUX is sampled at the Tsampling end
and it is hold until the next sampling. The sampled voltage is compared with 2V reference voltage and the error is
amplified. The error amplifier output reflects the load condition and controls the Toff time to regulate the output
voltage, thus constant output voltage can be achieved.
Constant Current Operation
When the sampled voltage is below 2V reference voltage and the error amplifier output reaches its maximum, thus
UTC UPSRB01A operates in constant-current (CC) mode. The CC point and maximum output power can be
externally adjusted by external current sense resistor Rcs. The larger Rcs, the smaller CC point is, and the smaller
output power becomes.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
4 of 7
QW-R103-095.a
UPSRB01A

Preliminary
LINEAR INTEGRATED CIRCUIT
OPERATION DESCRIPTION (Cont.)
Figure3. Adjustable output power by changing RCS
Figure4. Secondary current waveform
In CC operation, the CC loop control function of UTC UPSRB01A will keep a fixed proportion between secondary
inductance de-magnetization time (Tdemag) and switching cycle time (Tsw). The fixed proportion is
Tdemag 1
(2)
=
TSW
2
Thus the output current is given by:
Iout =
Tdemag 1 NP
1 NP
= ×
×I
×
× IPK ×
TSW
4 NS PK
2 NS
(3)
Current Sensing and Leading Edge Blanking
Cycle-by-cycle current limiting is offered in UTC UPSRB01A. The switch current is detected by a sense resistor
into the CS pin. When the power switch is turned on, a turn-on spike will occur on this resistor. A 500ns leading-edge
blanking is built in to avoid false-termination of the switching pulse so that the external RC filtering is no longer
needed.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
5 of 7
QW-R103-095.a
UPSRB01A

Preliminary
LINEAR INTEGRATED CIRCUIT
OPERATION DESCRIPTION (Cont.)
Drive BJT
The driver is a push pull stage with the supply voltage VDD. It provides the driving current for the external power
bipolar transistor. The output signal is current-limited to IOUT(SOURCE).
Protection Control
Good power supply system reliability is achieved with its comprehensive protection features including output
over-voltage protection, VDD over voltage protection, feedback loop open protection, Cycle-by-cycle current limiting,
short circuit protection, leading edge blanking and UVLO, etc.
VDD is supplied by transformer auxiliary winding output. The output of UTC UPSRB01A is shutdown when VDD
drops below VTH(OFF) and the power converter enters power on start-up sequence thereafter.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
6 of 7
QW-R103-095.a
UPSRB01A
Preliminary
LINEAR INTEGRATED CIRCUIT
TYPICAL APPLICATION CIRCUIT (5V/1A)

BOM
Reference
BD1
L1
C1
C2
C3
C4
C6
C8
D5,D7
D6
Component
BD 1A/600V
Choke
EC 4.7u F 400V 105°C
EC 4.7u F 400V 105°C
CC 1n F 1000V 1206
EC 2.2u F 50V 105°C
EC 680u F 10V 105°C
CC 22n F 50V 0805
UTC 1N4007
UTC SB340
Reference
R3
R1,R2
R4
R6
R7
R9
T1
F1
Q1
Component
R 2.4KΩ 1206 ±5%
R 4.7MΩ 1206 ±5%
R 330KΩ 1206 ±5%
R 20KΩ 0805 ±1%
R 3.3KΩ 0805 ±1%
R 1.1Ω 1206 ±5%
EE-16
FUSE 1A 250VAC
UTC MJE13003
UTC assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or
other parameters) listed in products specifications of any and all UTC products described or contained
herein. UTC products are not designed for use in life support appliances, devices or systems where
malfunction of these products can be reasonably expected to result in personal injury. Reproduction in
whole or in part is prohibited without the prior written consent of the copyright owner. The information
presented in this document does not form part of any quotation or contract, is believed to be accurate
and reliable and may be changed without notice.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
7 of 7
QW-R103-095.a
Similar pages