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PDF LT1548 Data sheet ( Hoja de datos )
| Número de pieza | LT1548 | |
| Descripción | High Precision CC/CV Primary-Side PWM Power Switch | |
| Fabricantes | Longtium Microelectronics | |
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Hay una vista previa y un enlace de descarga de LT1548 (archivo pdf) en la parte inferior de esta página. Total 10 Páginas | ||
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LT1548
High Precision CC/CV Primary-Side PWM Power Switch
GENERAL DESCRIPTION
LT1548 is a high performance offline
PWM Power switch for low power AC/DC
charger and adaptor 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 as well at large
load condition and it operates in PWM with
frequency reduction at light/medium load.
LT1548 offers power on soft start control
and protection coverage with auto-recovery
features including Cycle-by-Cycle current
limiting, VDD OVP, VDD clamp and UVLO.
Excellent EMI performance is achieved with
On-Bright proprietary frequency shuffling
technique. High precision constant voltage (CV)
and constant current (CC) can be achieved by
LT1548.
FEATURES
5% Constant Voltage Regulation, 5%
Constant Current Regulation at Universal
AC input
Primary-side Sensing and Regulation
Without TL431 and Opto-coupler
Programmable CV and CC Regulation
Adjustable Co白nsta光ntLCEuDrr升ent压an型d 驱Ou动tpu器t
Power Setting
Built-in Secondary Constant Current
Control with Primary Side Feedback
Built-in Adaptive Current Peak Regulation
Built-in Primary winding inductance
compensation
Programmable Cable drop Compensation
Power on Soft-start
2
Built-in Leading Edge Blanking (LEB)
Cycle-by-Cycle Current Limiting
VDD Under Voltage Lockout with
Hysteresis (UVLO)
VDD OVP,VDD Clamp
Offered in DIP8 package
APPLLICATIONS
Low Power AC/DC offline SMPS for :
Cell Phone Charger，Digital Cameras Charger
Small Power Adaptor
Auxiliary Power for PC, TV etc.
Linear Regulator/RCC Replacement
Xi′an Longtium Microelectronics Technology Developing Co., Ltd
（2011-AUG Version1.0）
1 /10
www.longtiumic.com
1 page  
LT1548
ELECTRICAL CHARACTERISTICS
(TA = 25OC, VDD=VDDG=16V, if not otherwise noted)
Symbol
Parameter
Test Conditions Min Typ Max Unit
Supply Voltage (VDD) Section
I DD ST
Standby Current
VDD=13V
5 20 uA
I DD op
Operation Current
UVLO(ON)
VDD Under Voltage
Lockout Enter
Operation supply
current INV=2V,
CS=0V,
VDD=VDDG=20V
-
2.5 3.5
VDD falling
7.5 8.5 10
mA
V
UVLO(OFF)
VDD Under Voltage
Lockout Exit
VDD rsing
13.5 14.5 16.0 V
VDD_clamp
Maximum VDD operation
voltage
IDD=10mA
30.5 32.5 34．5 V
OVP
Over voltage protection
Threshold
Ramp VDD until
gate shut down
27.5 29.5 31.5 V
Current Sense Input Section
TLEB
LEB time
540 ns
Vth_oc
Over current threshold
870 900 930 mV
Td_oc
OCP Propagation delay
150 ns
ZSENSE_IN
T_ss
Input Impedance
Soft start time
50 Koh
10 mms
Frequency Section
Freq_Max
IC Maximum frequency
66 72 78 KHz
Freq_Nom
System Nominal switch
frequency
60 KHz
Freq_startup
INV=0V, Comp=5V
14
KHz
△f/Freq
Frequency shuffling range
+/- 4 %
Error Amplifier section
Vref_EA
Reference voltage for EA
1.97 2
2.03 V
Gain DC gain of EA
60 dB
I_COMP_MAX
Max. Cable compensation
current
INV=2V, Comp=0V
42
uA
Power MOSFET Section
BVdss
Rdson
MOSFET Drain-Source
Breakdown Voltage
On Resistance
Static, Id=0.4A
600
5
V
Ώ
Note: Freq Max indicates IC internal maximum clock frequency. In system application, the
maximum operation frequency of 60KHz nominal occurs at maximum output power or the transition
point from CV to CC.
Xi′an Longtium Microelectronics Technology Developing Co., Ltd
（2011-AUG Version1.0）
5 / 10
www.longtiumic.com
5 Page | ||
| Páginas | Total 10 Páginas | |
| PDF Descargar | [ Datasheet LT1548.PDF ] | |
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