LYT4211-4218/4311-4318
™
LYTSwitch-4
High Power LED Driver IC Family
Single-Stage Accurate Primary-Side Constant Current (CC) Controller with
PFC for
Low-Line
Applications
with
TRIAC Dimming and Non-Dimming Options
Optimized for Different Applications and Power Levels
Part Number
LYT4211-LYT4218
LYT4311-LYT4318
Input Voltage Range
85-132 VAC
85-132 VAC
TRIAC Dimmable
No
Yes
Output Power Table
Product
LYT4x11E
LYT4x12E
LYT4x13E
LYT4x14E
LYT4x15E
LYT4x16E
LYT4x17E
LYT4x18E
Minimum Output Power Maximum Output Power
2.5 W
2.5 W
3.8 W
4.5 W
5.5 W
6.8 W
8.0 W
18 W
12 W
15 W
18 W
22 W
25 W
35 W
50 W
78 W
To read about
LYTSwitch-4 Low-Line
Click Here
LYT4221-4228/4321-4328
™
LYTSwitch-4
High Power LED Driver IC Family
Single-Stage Accurate Primary-Side Constant Current (CC) Controller with
PFC for
High-Line
Applications with TRIAC Dimming and Non-Dimming Options
Optimized for Different Applications and Power Levels
Part Number
LYT4221-LYT4228
LYT4321-LYT4328
Input Voltage Range
160-300 VAC
160-300 VAC
TRIAC Dimmable
No
Yes
Output Power Table
Product
LYT4x21E
LYT4x22E
LYT4x23E
LYT4x24E
LYT4x25E
LYT4x26E
LYT4x27E
LYT4x28E
Minimum Output Power Maximum Output Power
6W
6W
8W
9W
11 W
14 W
19 W
33 W
12 W
15 W
18 W
22 W
25 W
35 W
50 W
78 W
To read about
LYTSwitch-4 High-Line
Click Here
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LYT4211-4218/4311-4318
™
LYTSwitch-4
High Power LED Driver IC Family
Single-Stage Accurate Primary-Side Constant Current (CC) Controller with
PFC for Low-Line Applications with TRIAC Dimming and Non-Dimming Options
Product Highlights
•
•
•
•
•
•
•
Better than ±5% CC regulation
TRIAC dimmable to less than 5% output
Fast start-up
•
<250 ms at full brightness
•
<1s at 10% brightness
High power factor >0.9
Easily meets EN61000-3-2
•
Less than 10% THD in optimized designs
Up to 92% efficient
132 kHz switching frequency for small magnetics
AC
IN
D
V
LYTSwitch-4
BP
CONTROL
S
R
FB
High Performance, Combined Driver, Controller, Switch
The LYTSwitch-4 family enables off-line LED drivers with high
power factor which easily meet international requirements for
THD and harmonics. Output current is tightly regulated with
better than ±5% CC tolerance
1
. Efficiency of up to 92% is easily
achieved in typical applications.
Supports a Wide Selection of TRIAC Dimmers
The LYTSwitch-4 family provides excellent turn-on characteristics
for leading-edge and trailing-edge TRIAC dimming applications.
This results in drivers with a wide dimming range and fast
start-up, even when turning on from a low conduction angle –
large dimming ratio and low “pop-on” current.
Low Solution Cost and Long Lifetime
LYTSwitch-4 ICs are highly integrated and employ a primary-side
control technique that eliminates the optoisolator and reduces
component count. This allows the use of low-cost single-sided
printed circuit boards. Combining PFC and CC functions into a
single-stage also helps reduce cost and increase efficiency.
The 132 kHz switching frequency permits the use of small,
low-cost magnetics.
LED drivers using the LYTSwitch-4 family do not use primary-
side aluminum electrolytic bulk capacitors. This means greatly
extended driver lifetime, especially in bulb and other high
temperature applications.
PI-6800-050913
Figure 1.
Typical Schematic.
Optimized for Different Applications and Power Levels
Part Number
LYT4211-LYT4218
LYT4311-LYT4318
Input Voltage Range
85-132 VAC
85-132 VAC
TRIAC Dimmable
No
Yes
Output Power Table
1,2
Product
6
LYT4x11E
5
LYT4x12E
LYT4x13E
LYT4x14E
LYT4x15E
LYT4x16E
LYT4x17E
LYT4x18E
Minimum Output Power
3
Maximum Output Power
4
2.5 W
2.5 W
3.8 W
4.5 W
5.5 W
6.8 W
8.0 W
18 W
12 W
15 W
18 W
22 W
25 W
35 W
50 W
78 W
eSIP-7C (E Package)
Figure 2.
Package Options.
Table 1. Output Power Table.
Notes:
1. Performance for typical design. See Application Note.
2. Continuous power in an open-frame design with adequate heat sinking; device
local ambient of 70 °C. Power level calculated assuming a typical LED string
voltage and efficiency >80%.
3. Minimum output power requires C
BP
= 47
µF.
4. Maximum output power requires C
BP
= 4.7
µF.
5. LYT4311 C
BP
= 47
µF,
LYT4211 C
BP
= 4.7
µF.
6. Package: eSIP-7C (see Figure 2).
www.power.com
November 2014
This Product is Covered by Patents and/or Pending Patent Applications.
LYT4211-4218/4311-4318
Topology
Isolated Flyback
Buck
Tapped-Buck
Buck-Boost
Table 2.
Isolation
Yes
No
No
No
Efficiency
88%
92%
89%
90%
Cost
High
Low
Middle
Low
THD
Best
Good
Best
Best
Output Voltage
Any
Limited
Any
High-Voltage
Performance of Different Topologies in a Typical Non-Dimmable 10 W Low-Line Design.
Typical Circuit Schematic
Key Features
Flyback
Benefits
•
Provides isolated output
•
Supports widest range of output voltages
•
Very good THD performance
Limitations
•
Flyback transformer
•
Overall efficiency reduced by parasitic capacitance
and inductance in the transformer
•
Larger PCB area to meet isolation requirements
•
Requires additional components (primary clamp and bias)
•
Higher RMS switch and winding currents increases losses
and lowers efficiency
AC
IN
D
V
LYTSwitch-4
BP
CONTROL
S
R
FB
PI-6800-050913
Figure 3a. Typical Isolated Flyback Schematic.
Buck
Benefits
•
Highest efficiency
•
Lowest component count – small size
•
Simple low-cost power inductor
•
Low drain source voltage stress
•
Best EMI/lowest component count for filter
Limitations
•
Single input line voltage range
•
Output voltage <0.6
×
V
IN(AC)
×
1.41
•
Output voltage for low THD designs
•
Non-isolated
AC
IN
D
V
CONTROL
LYTSwitch-4
BP
S
R
FB
PI-6841-111813
Figure 3b. Typical Buck Schematic.
Tapped-Buck
Benefits
•
Ideal for low output voltage designs (<20 V)
•
High efficiency
•
Low component count
•
Simple low-cost tapped inductor
Limitations
•
Designs best suited for single input line voltage
•
Requires additional components (primary clamp)
•
Non-isolated
PI-6842-111813
AC
IN
LYTSwitch-4
D
V
CONTROL
BP
S
R
FB
Figure 3c. Typical Tapped-Buck Schematic.
Buck-Boost
Benefits
•
Ideal for non-isolated high output voltage designs
•
High efficiency
•
Low component count
•
Simple common low-cost power inductor can be used
•
Lowest THD
Limitations
•
Maximum V
OUT
is limited by MOSFET breakdown voltage
•
Single input line voltage range
•
Non-isolated
PI-6859-111813
AC
IN
D
V
CONTROL
LYTSwitch-4
BP
S
R
FB
Figure 3d. Typical Buck-Boost Schematic.
2
Rev. E 11/14
www.power.com
LYT4211-4218/4311-4318
BYPASS (BP)
BYPASS
CAPACITOR
SELECT
SOFT-START
TIMER
FAULT
PRESENT
5.9 V
REGULATOR
DRAIN (D)
HYSTERETIC
THERMAL
SHUTDOWN
-
I
LIM
M
I
AUTO-RESTART
COUNTER
5.9 V
5.0 V
VOLTAGE
MONITOR (V)
1V
STOP
LOGIC
JITTER
CLOCK
OSCILLATOR
3-V
T
OV
-
+
BYPASS PIN
UNDERVOLTAGE
Comparator
FB
OFF
DC
MAX
OCP
+
LINE
SENSE
FEEDBACK (FB)
V
BG
I
V
I
FB
FB
OFF
DC
MAX
PFC/CC
CONTROL
M
I
FEEDBACK
SENSE
REFERENCE (R)
6.4 V
REFERENCE
BLOCK
V
BG
Figure 4.
Functional Block Diagram.
Pin Functional Description
DRAIN (D) Pin:
This pin is the power FET drain connection. It also provides
internal operating current for both start-up and steady-state
operation.
SOURCE (S) Pin:
This pin is the power FET source connection. It is also the
ground reference for the BYPASS, FEEDBACK, REFERENCE
and VOLTAGE MONITOR pins.
BYPASS (BP) Pin:
This is the connection point for an external bypass capacitor for
the internally generated 5.9 V supply. This pin also provides
output power selection through choice of the BYPASS pin
capacitor value.
FEEDBACK (FB) Pin:
The FEEDBACK pin is used for output voltage feedback. The
current into the FEEDBACK pin is directly proportional to the
output voltage. The FEEDBACK pin also includes circuitry to
protect against open load and overload output conditions.
REFERENCE (R) Pin:
This pin is connected to an external precision resistor and is
used to configure for dimming (LYT4311-4318) and non-TRIAC
dimming (LYT4211-4218) modes of operation.
VOLTAGE MONITOR (V) Pin:
This pin interfaces with an external input line peak detector,
consisting of a rectifier, filter capacitor and resistors. The
applied current is used to control stop logic for overvoltage (OV),
provide feed-forward to control the output current and the
remote ON/OFF function.
Exposed Pad
(Backside) Internally
Connected to
SOURCE Pin (see
eSIP-7C Package
Drawing)
Figure 5.
Pin Configuration.
www.power.com
+
Gate
Driver
SenseFet
LEB
CURRENT LIMIT
COMPARATOR
-
I
LIM
V
SENSE
I
S
PI-6843-071112
SOURCE (S)
E Package (eSIP-7C)
(Top View)
5S
4 BP
3 FB
2V
1R
7D
PI-7076-062513
3
Rev. E 11/14
嵌入式系统
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