Datasheet

UNISONIC TECHNOLOGIES CO., LTD
UC1103
Preliminary
CMOS IC
HIGH PRECISION CC/CV
PRIMARY SIDE SWITCHING
REGULATOR

DESCRIPTION
The UTC UC1103 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 integrates PWM controller to enhance the
performance of discontinuous conduction mode (DCM) flyback
converters.
The UTC UC1103 operates in primary-side sensing and
regulation. Opto-coupler and TL431 could be eliminated. It also
provides off-time modulation to linearly decrease PWM frequency
under light-load conditions so that low standby power can be
achieved.
The UTC UC1103 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, VDD over voltage protection, VDD clamp, OTP,
leading edge blanking, VDD under voltage lockout, etc.

FEATURES
* High voltage startup
* ±5% constant voltage regulation at universal AC input
* High precision constant current regulation at universal AC input
* Primary side control without TL431 and opto-coupler
* Programmable CV and CC regulation
* Programmable cable compensation in CV mode
* Flyback topology in DCM operation
* Frequency hopping to reduce system EMI

SOP-8
* Driver MOSFET switch
* Built-in leading edge blanking
* Built-in primary winding inductance
compensation
* Gate output maximum voltage clamped at 15V
* Cycle-by-cycle current limiting
* Over voltage protection
* VDD under-voltage lockout
ORDERING INFORMATION
Ordering Number
UC1103G-S08-R
UC1103G-S08-R
Package
SOP-8
(1)Packing Type
(1) R: Tape Reel
(2)Package Type
(2) S08: SOP-8
(3)Green Package
(3) G: Halogen Free and Lead Free
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Copyright © 2015 Unisonic Technologies Co., Ltd
Packing
Tape Reel
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UC1103
Preliminary

MARKING

PIN CONFIGURATION

CMOS IC
CS
1
8
HV
GATE
2
7
NC
VDD
3
6
GND
COMR
4
5
VS
PIN DESCRIPTION
PIN NO.
1
2
3
4
5
6
7
8
PIN NAME
CS
GATE
VDD
COMR
VS
GND
NC
HV
DESCRIPTION
Current sense input.
Gate drive for power MOSFET.
Power supply.
Cable compensation.
The voltage feedback from the auxiliary winding.
Ground
No connect
High-voltage startup.
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UC1103

Preliminary
CMOS IC
BLOCK DIAGRAM
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UC1103

Preliminary
CMOS IC
ABSOLUTE MAXIMUM RATING
PARAMETER
SYMBOL
RATINGS
UNIT
HV Pin Input Voltage
VHV
500
V
Supply Voltage
VDD
30
V
Voltage at VS, CS, COMR to GND
-0.3~7.0
V
Power Dissipation (TA<50°C)
PD
660
mW
Operating Ambient Temperature
TA
-40~+105
°C
Operating Junction Temperature
TJ
-40~+150
°C
Storage Temperature Range
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.

THERMAL RESISTANCES CHARACTERISTICS
PARAMETER
Junction to Ambient
Junction to Case

SYMBOL
θJA
θJC
RATINGS
150
39
UNIT
°C/W
°C/W
ELECTRICAL CHARACTERISTICS (VDD=15V, TA=25°C, unless otherwise specified)
PARAMETER
SUPPLY SECTION
Turn-on Threshold Voltage
Turn-off Threshold Voltage
VDD OVP Protection
Operating Current
Green-Mode Operating Current
HV START-UP SECTION
Minimum Startup Voltage on HV Pin
Supply Current Drawn from Pin HV
Leakage Current after Startup
OSCILLATOR SECTION
Maximum Frequency
Minimum Frequency at CCM
Minimum Frequency at No-load
Frequency Hopping Range
Frequency Hopping Period
Frequency Variation vs. VDD Deviation
VOLTAGE SENSE SECTION
Reference Voltage for EA
Reference Voltage for CCM
Max. Cable Compensation Current
CURRENT SSENSE SECTION
Current Sense Threshold Voltage
OCP Propagation Delay
Leading Edge Blank Time
Soft Start Time
SYMBOL
VTH(ON)
VTH(OFF)
VDD_OVP
IDD-OP
IDD-GREEN
VHV-MIN
IHV
IHV-LC
fOSC-CM-MIN
fOSC-N-MIN
△f/freq
tFHR
fDV
VDD=10~25V
VVR
VVR_CCM
MIN
TYP
15
8
16
9
28
1.6
1.5
VDC=100V
HV=500V, VDD=VDD-OFF+1V
fOSC
MAX UNIT
17
10
2
50
V
mA
μA
53
kHz
kHz
Hz
kHz
ms
%
0.6
0.5
47
±1.5
50
13
300
±2.0
3
1
V
V
V
mA
mA
±2.5
2
ICABLE_MAX
2.475 2.525 2.625
0.5
25
V
V
uA
VCS
tD_OC
tLEB
tSS
800
90
600
10
mV
nS
nS
mS
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TEST CONDITIONS
200
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UC1103

Preliminary
CMOS IC
ELECTRICAL CHARACTERISTICS(Cont.)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
GATE DRIVE SECTION
Output Voltage Low
VOL
VDD=15V, Io_sink=20mA
Output Voltage High
VOH
VDD=15V, Io_source=20mA
5
Rising Time
tR
CL=1nF
Falling Time
tF
CL=1nF
Output Clamp Voltage
VCLAMP
VDD=25V
OTP SECTION
Threshold Temperature of OTP (Note)
TOTP
Note: When the over-temperature protection is activated, the power system enters auto restart
disabled.
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TYP
MAX UNIT
1.5
200
60
16
250
100
18
V
V
nS
nS
V
+150
°C
mode and output is
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UC1103

Preliminary
CMOS IC
OPERATION DESCRIPTION
The UTC UC1103 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. The device integrates PWM controller to enhance the
performance of discontinuous conduction mode (DCM) flyback converters.
High-Voltage Startup control
The HV pin of UTC UC1103 is connected to the line input through a resistor (100K is recommended). During
startup, the internal startup circuit in UTC UC1103 is enabled. Meanwhile, line input supplies a constant current to
charge the hold-up capacitor through the resistor. 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 UC1103 is as low as 1.6mA. 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
UC1103 captures the auxiliary winding feedback voltage at VS 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 VS, the VAUX is sampled at the Tsampling end
and it is hold until the next sampling. The sampled voltage is compared with 2.5V reference voltage and the error is
amplified. The error amplifier output reflects the load condition and controls the Toff time and the Ipk to regulate the
output voltage, thus constant output voltage can be achieved.
Constant Current Operation
When the sampled voltage is below 2.5V reference voltage and the error amplifier output reaches its maximum,
thus UTC UC1103 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.
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UC1103

Preliminary
CMOS IC
OPERATION DESCRIPTION(Cont.)
Figure3. Adjustable output power by changing Rcs
Figure4. Secondary current waveform
In CC operation, the CC loop control function of UTC UC1103 will keep a fixed proportion between secondary
inductance de-magnetization time (Tdemag) and switching cycle time (Tsw). The fixed proportion is
Tdemag 1
=
Tsw
2
(2)
1 NP
Tdemag 1 NP
×
× Ipk ×
= ×
× Ipk
2 NS
Tsw
4 NS
(3)
Thus the output current is given by:
Iout =
Programmable Cable Drop Compensation
UTC UC1103 has a built-in cable voltage drop compensation to achieve good load regulation. An offset voltage is
generated at VS pin by an internal current flowing into the resistor divider. The current is inversely proportional to the
voltage of COMR pin. As a result, it is inversely proportional to the output load current. The voltage drop across the
cable is compensated by this offset voltage at VS pin. It can also be programmed by adjusting the resistance of the
divider to compensate the drop for various cable lines used.
Current Sensing and Leading Edge Blanking
Cycle-by-cycle current limiting is offered in UTC UC1103. 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.
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UC1103

Preliminary
CMOS IC
OPERATION DESCRIPTION(Cont.)
Gate Output
The UTC UC1103 output stage is a fast totem-pole gate driver. Cross conduction has been avoided to minimize
heat dissipation, increase efficiency, and enhance reliability. The output driver is clamped at 15V to protect power
MOSFET transistors against undesired over-voltage gate signals.
Protection Control
Good power supply system reliability is achieved with its comprehensive protection features including VDD
over-voltage protection, VDD Clamp, GATE Clamp, Power on soft start, Cycle-by-cycle current limiting, short circuit
protection, leading edge blanking, OTP and UVLO, etc.
VDD is supplied by transformer auxiliary winding output. The output of UTC UC1103 is shutdown when VDD drops
below VTH(OFF) and the power converter enters power on start-up sequence thereafter.
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UC1103

Preliminary
CMOS IC
TYPICAL APPLICATION CIRCUIT (5V/2.4A)
BOM
Reference
BD1
L1
C1
C2
C3
C4
C5
C6
D4, D5
D6
Component
BD 2A/600V
Choke
EC 10μF/400V 105°C
EC 10μF/400V 105°C
CC 1nF/1000V 1206
EC 22μF/50V 105°C
CC 68nF/50V 0805
EC 1500μF/10V 105°C
Diode UTC 1N4007
Diode UTC MGBR10L45C
Reference
R1
R2
R7
R8
R9
R10
T1
F1
Q1
Component
R 200kΩ 1206 ±5%
R 2.4kΩ 1206 ±5%
R 39kΩ 0805 ±1%
R 10kΩ 0805 ±1%
R 1Ω 1206 ±5%
R 100kΩ 1206 ±5%
RM-6
FUSE 1A 250VAC
N-channel UTC 6N60L
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.
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