www.power.com

September 2015

Energy-Efficient, Accurate Primary-Side Regulation

CC/CV Switcher for LED Lighting Applications

LYT2002-2005

LYTSwitch-2 Family

This Product is Covered by Patents and/or Pending Patent Applications.

Output Power Table2

Product5

90-308 VAC

Enclosed Bulb3

Ballast Driver4

LYT2002D

5 W

6 W

LYT2003D

6 W

7 W

LYT2004D

7 W

8 W

LYT2004E/K

9 W

10 W

LYT2005E/K

10 W

12 W

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 T

J ≤ 100 °C.

4. Maximum practical continuous power in an open frame design with adequate

heat sinking, measured at +50 °C.

5. Packages: D: SO-8C, E: eSIP-7C, K: eSOP-12B.

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

This enhances production yield

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

•

Programmable switching frequency reduces transformer size

•

725 V switching power MOSFET enables clampless flyback designs

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

EcoSmart™– Energy Efficient

•

No-load consumption <30 mW1

•

No current sense resistors – maximizes efficiency

Green Package

•

All parts are halogen free and RoHS compliant

Applications

•

LED bulbs, down lights, luminaires, ballasts and T8 tubes

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.

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.

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.

Figure 1. Typical Flyback Implementation – Not a Simplified Circuit.

LYTSwitch-2

PI-7037a-051914

D

S

FB

BP

AC

IN