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부품번호 | EMD2055 기능 |
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기능 | PWM Step-Up DC/DC Converter | ||
제조업체 | Elite Semiconductor | ||
로고 | |||
전체 13 페이지수
ESMT/EMP
Preliminary
EMD2055
PWM Step-Up DC/DC Converter for Panel Backlight (11 WLEDs Driver)
General Description
The EMD2055 is a highly efficient, step-up DC/DC
converter for driving white LEDs. The device can
drive up to 11 serially connected white LEDs from a
single Li-Ion battery, or to drive multiple serial and
parallel combinations with a DC power supply from
2.5V to 5.5V. The EMD2055 uses current mode and
pulse-width modulated (PWM) operation. Its high
switching operation frequency of 1.0MHz allows the
system to use small inductor, input and output
capacitors. An internal compensation circuit can
reduce the external component count.
To safeguard the system, the EMD2055 includes
various protection circuits such as under-voltage
lockout, current limit, over voltage and thermal
shutdown. EMD2055 are available in the tiny
packages of SOT-23-6L and TDFN-8L (2x2mm).
Applications
Mobile Phone
Digital Still Cameras
Portable applications
MP3 Players
GPS Receivers
Features
Up to 11 WLEDs supports
Low Quiescent Current: 120 µA
Over Voltage Protection: 36.5V
Inherently Matched LED Current
Shutdown Current < 1µA
Reference Voltage 0.24V
PWM Dimming Control (100Hz~100kHz)
Internal Soft Start and Compensation
1.5A Internal power MOSFET Switch
Low Profile SOT-23-6 and TDFN-8L Packages
Typical Application (9S3P)
Fig. 1
Elite Semiconductor Memory Technology Inc./Elite MicroPower Inc.
Publication Date: Jan. 2013
Revision: 0.03 1/13
ESMT/EMP
Preliminary
EMD2055
Absolute Maximum Ratings
Devices are subjected to failure if they stay above absolute maximum ratings
Input Voltage
– 0.3V to 6V Operating Temperature Range
–40°C to 85°C
EN, VFB Voltages
– 0.3V to VIN
Storage Temperature
–65°C to 150°C
LX ,OUT Voltage
– 0.3V to 37V Junction Temperature
150°C
ESD Susceptibility
HBM 2kV
Lead Temperature (Soldering, 10 sec)
260°C
MM 200V
Thermal data
Package
SOT-23-5
TDFN-8
(2x2 mm)
Thermal resistance
θJA (Note 2)
θJC (Note 3)
θJA (Note 2)
θJC (Note 3)
Parameter
Junction-ambient
Junction-case
Junction-ambient
Junction-case
Value
250°C/W
81oC/W
165oC/W
24oC/W
Note 1: TJ is a function of the ambient temperature TA and power dissipation PD (TJ = TA + (PD) * (165°C/W)).
Note 2: θJA is measured in the natural convection at TA=25℃ on a highly effective thermal conductivity test board
(2 layers , 2S0P ) according to the JEDEC 51-7 thermal measurement standard.
Note 3: θJC represents the heat resistance between the chip and the package top case.
Electrical Characteristics
(Vcc = 3.7V, TA = 25°C, unless otherwise specified.)
PARAMETER
TEST CONDITION
Under Voltage Lock Out
Supply Current
Continuously Switching
Quiescent Current
No Switching, VFB = 1V
Shutdown Current
VEN < 0.4V
Operation Frequency
Maximum Duty Cycle
Feedback Voltage
Thermal Shutdown Protection
Thermal Shutdown Hysteresis
Ron
Current Limit
Isw = 200mA
Shutdown Voltage Low
Enable Voltage High
EN Leakage Current
Maximum Output Voltage
OVP
OVP Hysteresis
MIN
1.8
0.8
93
0.228
0.4
0.2
TYP
120
1.0
95
0.240
165
20
0.5
1.5
1.3
36
41
1
MAX
2.4
1
1
1.2
0.252
0.8
1.2
3
UNIT
V
mA
µA
uA
MHz
%
V
℃
℃
ohm
A
V
V
µA
V
V
V
Elite Semiconductor Memory Technology Inc./Elite MicroPower Inc.
Publication Date: Jan. 2013
Revision: 0.03 4/13
4페이지 ESMT/EMP
Application Information
Detailed Description
The EMD2055 is a constant frequency, current-mode boost DC-DC converter which can drive up to WLEDs
11S1P ~ 9S3P, depending on the input voltage range. The device can provide the well matched output
current through each WLED serial chain to obtain uniform illumination. The fast operation frequency allows
smaller inductor and input/output capacitors to be used.
During normal operation, the internal oscillator sends a pulse signal to set latch and turn on internal MOSFET
each duty circle. A current sense voltage sums MOSFET current and slope signal connected to the negative
terminal of the PWM comparator. When this signal voltage exceeds output voltage of the error amplifier, the
PWM comparator sends a signal to reset the latch and turn off internal MOSFET. The output voltage of the error
amplifier is magnified from the difference between reference voltage and feedback voltage. If the reference
voltage is higher than feedback voltage, more current is delivered to the output; otherwise, less current is
delivered.
UVLO
The EMD2055 provides Under-Voltage-Lock-Out (UVLO) protection. When VIN is lowered below UVLO threshold,
the UVLO circuit will send a signal to turn off the internal power MOSFET, which will stop supplying output
current. The 100mV hysteresis circuit in the UVLO circuit can prevent supply transients from causing a false
restart. Once the VIN exceeds UVLO threshold again, the device will unlock the latch and turn on the internal
power MOSFET to continue the normal operation.
Enable / Disable
The EMD2055 enters shutdown mode when EN pin voltage is less than 0.4V. During shutdown mode, all internal
circuits of the EMD2055 are turned off and the quiescent current is reduced to less than 1uA. When the EN pin
voltage is higher than 1.2V, the device will start operation.
The EN pin can also be used for dimming control by using a PWM modulated signal. The frequency of this PWM
signal can range from 100Hz to 100kHz. The average LED driving current is directly proportional to the duty
cycle of the PWM duty cycle, i.e., 0% duty cycle corresponding to zero WLEDs current and 100% duty cycle
corresponding to full WLEDs current.
OVP
When any of the serially connected WLEDs chain is open, the boost control loop behaves as an open loop
operation, which may cause damage on the LX pin due to excessive voltage. In order to prevent this damage
from happening, the EMD2055 provides an Over-Voltage-Protection (OVP) circuit, with the protection
threshold set at 41V. When LX pin exceeds 41V, the internal operation will be shut off.
Elite Semiconductor Memory Technology Inc./Elite MicroPower Inc.
Publication Date: Jan. 2013
Revision: 0.03 7/13
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부품번호 | 상세설명 및 기능 | 제조사 |
EMD2055 | PWM Step-Up DC/DC Converter | Elite Semiconductor |
EMD2055-00FK08NRR | PWM Step-Up DC/DC Converter | Elite Semiconductor |
DataSheet.kr | 2020 | 연락처 | 링크모음 | 검색 | 사이트맵 |