Datasheet

UNISONIC TECHNOLOGIES CO., LTD
US1652
Preliminary
CMOS IC
PRIMARY-SIDE REGULATION
PWM POWER SWITCH

DESCRIPTION
The UTC US1652 is a primary control 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 US1652 operates in primary-side sensing and
regulation. Opto-coupler and TL431 could be eliminated. It
operates in fixed frequency mode at large load conditions,
frequency reduction mode at light/medium load and ‘Extended
burst mode’ at No/light load conditions. So that low standby power
can be achieved.
The UTC US1652 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
* Programmable CV and CC regulation
* Primary-side sensing and regulation with No TL431 and
opto-coupler
* Multi-mode operation for high efficiency
* Adjustable constant current and output power setting
* Power on soft-start time (4ms)
* Frequency shuffling and adjustable gate drive greatly
improving EMI

DIP-8
* ”Extended burst mode control” for improved efficiency
and minimum standby design
* Built-in leading edge blanking (LEB)
* VDD under voltage lockout
* VDD over voltage shutdown and clamp
* Cycle-by-Cycle current limiting
* Fail-safe protection for open loop fault condition
* Auto-restart in over voltage condition
ORDERING INFORMATION
Ordering Number
Lead Free
US1652L-D08-T
Halogen Free
US1652G-D08-T
Package
Packing
DIP-8
Tube
US1652L-D08-T
(1)Packing Type
(1) T: Tube
(2)Package Type
(2) D08: DIP-8
(3)Green Package
(3) L: Lead Free, G: Halogen Free and Lead Free
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Copyright © 2015 Unisonic Technologies Co., Ltd
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US1652
Preliminary

MARKING

PIN CONFIGURATION

VDDG 1
8
GND
VDD 2
7
GND
INV 3
6
Drain
CS 4
5
Drain
PIN DESCRIPTION
PIN NO.
1
2
PIN NAME
VDDG
VDD
3
INV
4
5, 6
7, 8
CS
Drain
GND

CMOS IC
DESCRIPTION
Internal gate driver power supply
IC DC power supply input
Inverting input of error amplifier (EA). Connected to resistor divider from primary sensing
winding reflecting output voltage. PWM duty cycle is determined by EA output and
current sense signal at pin 4.
Current sense input
HV MOSFET Drain Pin. The Drain pin is connected to the primary lead of the transformer
Ground
BLOCK DIAGRAM
VDD
2
VDDG
1
5/6 Drain
Regulator & Por
Vref
Logic
core
Drive
Power
MOSFET
OVP
Softstart
30V
CC/CV
controller
INV 3
LEB
PWM
1.25V
4 CS
0.82V
7/8
GND
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US1652

Preliminary
CMOS IC
ABSOLUTE MAXIMUM RATING (TA=25°C, unless otherwise specified)
PARAMETER
SYMBOL
RATINGS
UNIT
Drain Voltage (Off State)
BVDSS
-0.3~650
V
VDD Voltage
VDD
-0.3~33
V
VDDG Voltage
VDDG
-0.3~33
V
VDD Zener Clamp Continuous Current
IDD_clamp
10
mA
CS Input Voltage
VCS
-0.3~7
V
INV Input Voltage
Vinv
-0.3~7
V
Operating Junction Temperature
TJ
-20~150
°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=VDDG=16V, unless otherwise specified)
PARAMETER
Supply Voltage (VDD) Section
Standby Current
Operation Current
SYMBOL
IDD ST
IDD op
VDD Under Voltage Lockout Enter
VDD Under Voltage Lockout Exit
UVLO(ON)
UVLO(OFF)
Over Voltage Protection Voltage
OVP(ON)
IDD=10mA
Current Sense Input Section
LEB Time
VTH_OC_test
Propagation Delay
Input Impedance
Soft Start Time
CV Section
Normal Mode Frequency
Burst Mode Base Frequency
Frequency Shuffling Range
CC Section
Oscillation Frequency
Error Amplifier section
Reference Voltage for EA
DC Gain of the EA
Unity Gain Bandwidth
Power MOSFET Section
Mos Drain-Source Breakdown
Voltage
Static Drain to Source On
Resistance
OTP SECTION
Threshold Temperature of OTP
(Note)
TEST CONDITIONS
TYP
MAX
UNIT
5
10
μA
1.0
2.0
mA
7.5
14.0
8.5
15
9.5
16.0
V
V
28.5
30.0
31.5
V
VDD=13V
Operation Supply Current
INV=1.25V, CS=0V, VDD=VDDG=20V
CS=0V,INV=1V Ramp up VDD Until
Gate Clock is Off
VDD_clamp
33
TLEB
Vth_oc
Td_oc
780
ZSENSE_IN
T_ss
Freq
Freq_Burst
△f/Freq
Freq
45
Minimum frequency
Maximum frequency
VREF_EA
Gdc
GBW
1.2
820
300
50
4
50
22
±4
V
860
55
12
50
1.21
1.25
50
37.5
μs
mV
ns
KΩ
ms
KHz
KHz
%
KHz
KHz
1.29
V
dB
kHz
BVDSS
650
V
RDS(ON)
6
Ω
TOTP
+150
°C
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
MIN
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US1652

Preliminary
CMOS IC
OPERATION DESCRIPTION
The UTC US1652 is a primary control 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
achievegood CV/CC performance. The device integrates PWM controller to enhance the performance of
discontinuous conduction mode (DCM) flyback converters.
Startup Current and Start up Control
The VDD pin of UTC US1652 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 US1652 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 US1652 is as low as 1mA. Good efficiency and very low standby power can be
achieved.
Soft Start Control
The UTC US1652 features an internal 4ms soft start to minimize the component electrical over-stress during
power on startup. As soon as VDD reaches UVLO (OFF), the control algorithm will ramp peak current voltage
threshold gradually from nearly zero to normal setting of 0.82V. Every restart is a soft start.
Constant Voltage Operation
The UTC US1652 is designed to produce good CC/CV control characteristic as shown in the Fig. 1.
To support UTC US1652 proprietary CC/CV control, system needs to be designed in DCM mode for flyback
system. When INV is equivalent or larger than 1.25V, the system works in CV control, In CV operation, the output
voltage is sensed on the primary side and the sensed signal controls the duty cycle through a built-in error amplifier
(EA). Connected to a resistor divider from the primary side sensing winding, the inverting input of the Error Amplifier
(EA) is compared to an internal reference voltage of 1.25V to regulate the output voltage. The EA output is internally
connected to the PWM generator and controls the duty cycle.
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US1652

Preliminary
CMOS IC
OPERATION DESCRIPTION (Cont.)
Constant Current Operation
When INV lower than 1.25V, the system works in CC control, In CC operation, the CC point and maximum output
power can be externally adjusted by external current sense resistor Rcs. The larger Rcs, the saller CC point is, and
the smaller output power becomes, and vice versa as shown in Fig.2.
VO
Large RS
Small RS
IO
Fig 2. Adjustable output power by changing RS
In charger applications, a discharged battery charging starts in the CC portion of the curve until it is nearly full
charged and smoothly switches to operate in CV portion of the curve.
In an AC/DC adapter, the normal operation occurs only on the CV portion of the curve. The CC portion provides
added cycle-by-cycle current limiting protection.
Extended Burst Mode Operation
At light load or zero load condition, most of the power dissipation in a switching mode power supply is from
switching loss, the core loss of the transformer and the loss on the snubber circuit. The magnitude of power loss is in
proportion to the switching frequency. Lower switching frequency leads to the reduction on the power loss and thus
conserves the energy.
The UTC US1652 self adjusts the switching frequency according to the loading condition. The switch frequency is
reduced at light/no load condition to improve the conversion efficiency. At light load/no load condition, the output of
the Error amplifier (EA) drops below the burst mode threshold level and device enters Burst Mode control. The
frequency control also eliminates the audio noise at any loading conditions.
Operation switching frequency
The switching frequency of UTC US1652 is internally set and adjusted according to CC/CV operation. No
external frequency setting components are required.
Frequency shuffling for EMI improvement
The frequency Shuffling/jittering (switching frequency modulation) is implemented in UTC US1652. The
oscillation frequency is modulated with a pseudo random source so that the tone energy is spread out. The spread
spectrum minimizes the conduction band EMI and therefore eases the system design.
Current Sensing and Leading Edge Blanking
Cycle-by-cycle current limiting is offered in UTC US1652. 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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US1652

Preliminary
CMOS IC
OPERATION DESCRIPTION (Cont.)
Adjustable Drive Capability
The internal power MOSFET in UTC US1652 is driven by a dedicated gate driver for power switch control. Too
weak the gate drive strength results in higher conduction and switch loss of MOSFET while too strong gate drive
compromises EMI. A good tradeoff is achieved through the built-in totem pole gate design with right output strength
control. The gate drive strength can be adjusted externally by a resistor connected between VDD and VDDG, The low
idle loss and good EMI system design is possible with this dedicated control scheme.
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 US1652 is shutdown when VDD drops
below VTH(OFF) and the power converter enters power on start-up sequence thereafter.
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US1652
Preliminary
CMOS IC
TYPICAL APPLICATION CIRCUIT (9V/0.5A)

L
F1
3
BD1 4
1
2
N
C1
Is
L1
T1
R4
R2
R1
C2
R3
D4
C4
D3
Ns C6
Np
Vo
R8
Vo
Io
D2
C3
C5
R9
R5
D1
VDD
VDDG
DRAIN
UTC
INV US1652 CS
R6
BOM
Reference
BD1
L1
C1,C2
C3
C4
C5
C6
D1, D2, D4
D3
R1
Component
BD 1A/600V
1mH 6x8mm
EC 4.7μF 400V 105°C
EC 4.7μF 50V 105°C
CC 1n F 1000V 1206
CC 0.33μF 50V 0805
EC 560μF 10V 105°C
Diode UTC 1N4007
Diode UTC SB360
R 2.4KΩ 1206 ±5%
GND
Reference
R2,R3
R4
R5
R6
R7
R8
R9
T1
F1
CY1
Na
CY1
R7
Component
R 1.5MΩ 1206 ±5%
R 200KΩ 1206 ±5%
R 47KΩ 0805 ±1%
R 3KΩ 0805 ±1%
R 3Ω 1206 ±5%
R 2.4KΩ 1206 ±5%
R 470Ω 0805 ±5%
EE-16
FUSE 1A 250VAC
Y/C 1000p F 250V
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
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