Energy-Efficient, Accurate Primary-Side Regulation CC Switcher LED Lighting Applications
Figure 1. Typical Flyback Implementation – Not a Simplified Circuit.
Data Sheets

LYTSwitch-2 Data Sheet
Energy-Efficient, Accurate Primary-Side Regulation CC/CV Switcher for LED Lighting Applications
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Product Details
Description
LYTSwitch-2 dramatically simplifies low power CC LED drivers by eliminating the optocoupler and secondary control circuitry. The family introduces a revolutionary control technique to provide very tight output current regulation, compensating for transformer and external component variations, and device parameter tolerances as well as input voltage variations.
The device incorporates a 725 V power MOSFET, a novel 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.
Product Highlights
Accurate CC Regulation (< ±3% typical)
- Transformer inductance variation
- External component changes with temperature
- Input line voltage variations – this ensures accurate regulation in production
Highly Reliable, Small Size Designs
- Eliminates the optocoupler and secondary CC control circuitry
- Eliminates control loop compensation circuitry
- Frequency jittering greatly reduces EMI filter cost
- Programmable switching frequency reduces transformer size
- 725 V Switching 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
- Reduced field returns
- 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
- Halogen free and RoHS compliant package
Applications
- LED bulbs, downlights, luminaires, ballasts and T8 tubes
Applications
Power Table
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 |
LYT2004K/E | 9 W | 10 W |
LYT2005K/E | 10 W | 12 W |
Notes:
- Nominal input and bias supply applied to BYPASS pin.
- Performance for typical design.
- Maximum continuous power in a typical non-ventilated bulb measured at ±50 °C ambient, device TJ ≤ 100 °C.
- Maximum practical continuous power in an open frame design with adequate heat sinking, measured at +50 °C.
- Packages: D: SO-8C, E: eSIP-7C, K: eSOP-12B.