LYT2002-2005
LYTSwitch-2 Family
Energy-Efficient, Accurate Primary-Side Regulation
CC/CV Switcher for LED Lighting Applications
Product Highlights
Accurate CC Regulation, Meets ±3% in a Typical
Design1
Controller Automatically Compensates For:
• Transformer inductance variation
• External component changes with temperature
• Input line voltage variations
AC
IN
D
S
FB
BP
This enhances production yield
LYTSwitch-2
Cost-Effective, Small Size Designs
• Eliminates the optocoupler and secondary CC control circuitry
• Eliminates control loop compensation circuitry
• Frequency-jitter greatly reduces EMI filter cost
PI-7037a-051914
• Programmable switching frequency reduces transformer size
• 725 V switching power MOSFET enables clampless flyback designs
Figure 1. Typical Flyback Implementation – Not a Simplified Circuit.
Advanced Protection/Safety Features
• Auto-restart protection reduces power delivered by >90% for output
short-circuit and control loop faults (open and short-circuit components)
• Hysteretic thermal shutdown – with automatic recovery
• Meets high-voltage creepage requirements between DRAIN and all
other pins both on the PCB and at the package
2
Output Power Table
EcoSmart™– Energy Efficient
90-308 VAC
• No-load consumption <30 mW1
Product5
Enclosed Bulb3
Ballast Driver4
• No current sense resistors – maximizes efficiency
Green Package
LYT2002D
LYT2003D
LYT2004D
LYT2004E/K
LYT2005E/K
5 W
6 W
7 W
9 W
10 W
6 W
7 W
• All parts are halogen free and RoHS compliant
Applications
• LED bulbs, down lights, luminaires, ballasts and T8 tubes
8 W
10 W
12 W
Description
The LYTSwitch™-2 family of ICs dramatically simplifies low power CC
LED drivers by eliminating the optocoupler and secondary control
circuitry. The family introduces a revolutionary control technique which
provides accurate output current regulation, compensating for
transformer and external component variations, and device parameter
tolerances as well as input voltage variations.
Table 1. Output Power Table.
Notes:
1. Nominal input and bias supply applied to BYPASS pin.
2. Performance for typical design.
3. Maximum continuous power in a typical non-ventilated bulb measured at +50
°C ambient, device TJ ≤ 100 °C.
4. Maximum practical continuous power in an open frame design with adequate
heat sinking, measured at +50 °C.
The device incorporates a high-voltage switching MOSFET, an ON/OFF
control state-machine, a high-voltage switched current source for
self-biasing, frequency jitter to reduce EMI, cycle-by-cycle current limit
and hysteretic thermal shutdown circuitry into a monolithic IC. This high
level of integration enables cost-effective designs with very few
external components, reducing solution cost and driver size.
5. Packages: D: SO-8C, E: eSIP-7C, K: eSOP-12B.
LYTSwitch-2 parts minimize energy consumption when the output is
unloaded. Practical designs can easily achieve less than 30 mW
no-load consumption.
The 725 V power MOSFET used in LYTSwitch-2 devices increases the
circuits’ ability to withstand input surge. In addition, each package is
designed to maximize the creepage distance between high-voltage pins
and logic level inputs. This increased pin spacing increases driver
lifetime and reliability in polluted environments. These in-built protec-
tion features also protect the entire circuit from excess temperature
operation, increasing lifetime in thermally challenging environments.
www.power.com
September 2015
This Product is Covered by Patents and/or Pending Patent Applications.