EC4318 [E-CMOS]
Offiline Step- down Buck LED Driver IC with APFC;
| 型号： | EC4318 |
| 厂家： | 
E-CMOS Corporation |
| 描述： | Offiline Step- down Buck LED Driver IC with APFC 功率因数校正 |
| 文件： | 总7页 (文件大小：208K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Offiline Step- down Buck LED Driver IC with APFC
EC4318
General Description
Features
The EC4318 is a high precision non-isolated buck driver
with APFC, specially designed for universal input offline
constant current LED lighting, and reach out low THD.
Operating in critical conduction mode, the power MOSFET
switching loss is reduced and the inductor is fully utilized.
By integrating a 500V power MOSFET, the fewest external
components, and cutting-edge circuit design, output ability
can be precisely controlled in the most competitive method
of all kinds. EC4318 adopts floating ground structure,
inductor current is hence sensed during the whole
switching cycle, which generates precise output current,
line and load regulation when being applied in system.
EC4318 also features full protection function to enhance
reliability on board, including LED Open / Short circuit
protection, OVP/UVP/OTP (Self-reduce)/OCP current
sensing open protection and so on.
ꢀ
High Power Factor, ultra- low THD
ꢀ Valley Switch, High Efficiency, LOW EMI
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
High- V MOSFET embedded
Thermal Regulation Compensation
±3% Output Current Accuracy
Universal AC input
Auto Induction Compensate
Auto Output Voltage adaption
Full Protection Features: ( LED O/S CKT; OTP
OCP; OVP/UVP)
ꢀ
ꢀ
Auto Recovery to default
Fewest external components required on board
Applications
ꢀ
LED High Brightness Lighting
ꢀ
Light Bulb, Light Tube
Typical Application
E-CMOS Corp. (www.ecmos.com.tw)
Page 1 of 7
4E22N-Rev.P001
Offiline Step- down Buck LED Driver IC with APFC
EC4318
Pin Configuration
EC4318 performed in SOP-8 Package shown as below：
Pin Definition
Pin
Pin#
Feature Description
Name
Loop Compensation Node. This pin connects a capacitor to GND for
stabilization of the control
COMP
1
Power Supply Pin. Connect a bypass capacitor from this pin to GND
Feedback Voltage Input Pin. This pin detects the inductor
demagnetization signal and the output voltage.
VCC
FB
2
3
4
Current Sense Pin. Connect a resistor to GND to sense the inductor current;
Source of the
CS
Drain of the internal HV MOSFET
Drain of the internal HV MODFET
Ground
Drain
Drain
GND
GND
5
6
7
8
Ground
Ordering Information
EC4318 NN XX X
R : Tape Reel
M1：SOP-8L
Part No.
Package type
Marking
Remark
EC4318
LLLLL
1. LLLLL：LOT NO.
2. YYWW：Date code
3. T： Tracking code
EC4318NNM1R
SOP-8L
YYWWT
E-CMOS Corp. (www.ecmos.com.tw)
Page 2 of 7
4E22N-Rev.P001
Offiline Step- down Buck LED Driver IC with APFC
EC4318
Block Diagram
Absolute Maximun RatingꢀNote 1ꢁ
Symbol
VCC
Parameter
Range
-0.3~ clamp Voltage
-0.3~500
-0.3~7
Input voltage
V
V
VD
Internal HV MOSFET Drain to Source
Current sense pin input voltage
Feed back pin input voltage
Compensation pin voltage
Power dissipation（Note2）
Maximum junction temperature
Storage temperature
VCS
V
VFB
-0.3~7
V
VCOMP
PDMAX
TJ
-0.3~7
V
0.45
W
℃
℃
160
TSTG
-55~150
Note 1: Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. Under “recommended operating
conditions” the device operation is assured, but some particular parameter may not be achieved. The electrical characteristics table defines the operation
range of the device, the electrical characteristics is assured on DC and AC voltage by test program. For the parameters without minimum and maximum
value in the EC table, the typical value defines the operation range, the accuracy is not guaranteed by spec.
Note 2: The maximum power dissipation decrease if temperature rise, it is decided by TJMAX, θJA, and environment temperature (TA). The maximum
power dissipation is the lower one between PDMAX = (TJMAX - TA)/ θJA and the number listed in the maximum table.
Recommended Operating Condition
Condition
Parameter
≤12
Unit
W
85~ 264Vac (full range)
175~264Vac (single range)
Operating temperature
Vac input
TA
≤18
W
℃
-20~85
E-CMOS Corp. (www.ecmos.com.tw)
Page 3 of 7
4E22N-Rev.P001
Offiline Step- down Buck LED Driver IC with APFC
EC4318
Electrical Characteristics (Unless otherwise specified, VCC=8V and TA =25 ℃ )
Symbol
Parameter
Condition
Min.
7.5
Typ.
Max.
Unit
Supply Voltage Section
VCC_clamp
ICC_clamp
VCC_ST
Vuvlo_HYS
Ist
VCC clamp Voltage
VCC clamp Current
Start-up Voltage
8.0
8.5
5
V
mA
V
VCC rising
VCC falling
7.07
7.57
1.32
70
8.07
UVLO Hysteresis Voltage
Start-up Current
V
VCC < VCC_ST - 0.5V
100
600
uA
uA
Iop
Operating Current
400
Current Sensing Section
Vocp
TLEB
Td
OCP Peak Voltage Limitation
1
V
Leading Edge Blanking Time
for Current Sense
350
200
ns
ns
Switch off Delay Time
Compensation Section
Internal Driving Section
Feedback Section
VREF
VCL
Internal Reference Voltage
COMP Low Clamp Voltage
COMP High Clamp Voltage
194
200
1.5
4.0
206
mV
V
VCH
V
TOFF_MIN
TON_MAX
TOFF_Max
Minimum Off Time
Maximum On Time
Maximum Off Time
3
us
us
us
20
100
FB Over Voltage Protection
Threshold
VFB
1.6
0.2
V
V
FB Falling Edge Threshold
Voltage
VZCD
High V MOSFET Section
VGS=10V/IDS=0.5A
RDSON
VDS
D-S on resistance
5
ꢀ
D-S breakdown Voltage
VGS=0V/IDS=250uA
500
V
Over Temp. Protection Sction
Tcomp
Thermal regulation Temp.
150
TSD
OTP Shut Down Temp.
160
30
TSD_HYS
Shut Down Hysteresis Temp.
E-CMOS Corp. (www.ecmos.com.tw)
Page 4 of 7
4E22N-Rev.P001
Offiline Step- down Buck LED Driver IC with APFC
EC4318
Application Info.
Output Current control
EC4318 is a high precision Active PFC driver which
integrates 500V power MOSFET, specifically designed
for non-isolated buck offline constant current LED lighting.
Even when switching in critical conduction condition,
EC4318 achieves high power factor, high efficiency and
ultra- low THD.
The EC4318 utilizes floating ground structure. The inductor
current is sensed during the whole switching cycle, hence it
achieves high precision output current and perfect line and
load regulation. The current in LED can be calculated by
equation of:
Start- up
Where 200mV is the internal reference voltage, and Rcs is
the value of current- sensing resistor.
With ultra- low start- up power (Typ.@70uA, Max. @
100uA)ꢂwhen it is applied at Vac = 85V to start- upꢂ
the start- up Resistance can be calculated in below ꢃ
Feedback Voltage measurement (OVP)
Voltage on FB pin determines operating state on board ꢂ
when it reaches over 1.6V(Typ.) , EC4318 would sense
and turn into Over- Voltage Protection modeꢂ and system
is thus jump to power- saving “ hiccup mode” ꢂOVP
voltage is generated byꢃ
Chip Power supply and consumption
After EC4318 being started-upꢂthe rectifier D6 is crucial
to adopt fast recovery Diode. The formula of Current- limit
resistance R4 would beꢃ
Please refer to typical application schematic to find R2 &
R3, in which R3=10K,ꢀ15K Max., and 8.2K Min.ꢁꢂin
above formula, the Constant 1.6 can be put 1.3 when
designing systems, Set Vovp= 90V, we can come out
R2=552K from above equation, herewith, we adopt 560K
resistor instead. As VFB is between 1.3-1.9, when
choosing the withstand voltage of C4, It is recommended to
set @ 1.9ꢂhence, Vovp =1.9*ꢀ10+560ꢁ/10 =108Vꢂ
moreover, the Withstand Voltage of C4 must be over
Vovpꢂherein We choose C4 @ 200V. After EC4318 falls
in “hiccup mode”, the output voltage is automatically
sensed constantly in working cycles. When output voltage
is beneath Vovp, system would recover to normal function
state.
In which “D” stands for duty Cycleꢂand 400uA is normal
operating current of EC4318 ꢂVLED is output loading
voltage. Power consumption of this certain Resistor can be
calculated atꢃ
For instanceꢃwhen Solution requiresꢃ
Vac in= 180~260VꢂVout= 36~80VꢂIout= 240m Then, in
low range of Vac in=180V; Vout =36V => R4 could be
generated in the following calculation:
D=36/180/1.414=0.141, R4=(1-0.141)*(36-9)/400uA=58K;
In high range of Vac in= 260VꢂVout= 80Vꢂthen
D=80/260/1.414=0.218ꢂand the power consumption
of resistance isꢃ
P=ꢀ80-9ꢁ*ꢀ80-9ꢁ/58 * (1-0.218)=68 mWꢄ
E-CMOS Corp. (www.ecmos.com.tw)
Page 5 of 7
4E22N-Rev.P001
Offiline Step- down Buck LED Driver IC with APFC
EC4318
LED Open/ Short Protection
The Area of Power Loop
When the LED is open circuit, the output voltage will
gradually rise up. The output voltage is sensed by the FB
pin when power MOSFET is turned off. When FB voltage
reaches the OVP threshold, it will trigger fault logic and the
system stops switching. When the LED is shorted circuit,
the system will work under 10kHz switching frequency.
Meanwhile, the output voltage is low and the VCC pin
cannot be charged up by the output voltage, so the VCC pin
voltage will gradually decrease and finally reaches the
UVLO threshold.
The area of main current loop should be as small as
possible to reduce EMI radiation.
FB Pin
The feedback resistor divider should be as close as
possible to the FB pin, and the trace must keeps away from
dynamic node of the inductor (DRAIN Pin trace), otherwise
the FB pin OVP function might have risk to be mis-
triggered by noise in system.
DRAIN Pin
Thermal Regulation (Over Temp. Protection)
The EC4318 integrates thermal regulation function. When
the system is over temperature, the output current is
gradually reduced; the output power and thermal
dissipation are also reduced. The system temperature is
regulated and the system reliability is improved. The
thermal regulation temperature is set to 150℃ internally.
To increase the copper area of DRAIN pin for better
thermal dissipation. However, over- enlarged copper pad
might also compromise EMI performance. Please leverage.
Filtering input Capacitor
With purposes to gain higher power factor, this Cap. Is
suggested to set @ 10-100nF
PCB Layouts
The following guidelines is recommended in EC4318 PCB
layout:
Bypass Capacitor:
The bypass capacitor on VCC pin should be as close as
possible to the VCC and GND pins.
Ground Path:
The power ground path for current sense resistor should
be short and wide, and it should be as close as possible to
the IC ground pins, otherwise the LED output current
accuracy may be affected. The IC signal ground for COMP
and FB components should be connected to the IC GND
pins with short traces, and should be away from the power
ground path.
E-CMOS Corp. (www.ecmos.com.tw)
Page 6 of 7
4E22N-Rev.P001
Offiline Step- down Buck LED Driver IC with APFC
EC4318
Package Information
E-CMOS Corp. (www.ecmos.com.tw)
Page 7 of 7
4E22N-Rev.P001
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