Single-Stage LED Driver IC with Combined PFC and Constant Current Output for Buck Topology

Data Sheets

Product Details

The LYTSwitch™-1 family is ideal for single-stage, high PF constant current LED bulbs and tubes.

The family incorporates a high-voltage MOSFET with a variable on-time CrM controller. Extensive protection features with minimum external components provide industry leading power density and functionality. The devices can be used in high-side or low-side non-isolated buck topology.

The CrM operation results in low turn-on losses and reduces cost of output diode (slower reverse recovery).

Device power capability is related to the output voltage as illustrated in Table 1. The internal current limit of the device dictates the size selection based on output voltage and power.


Key Features

  • Single-Stage PFC + Accurate CC Output
    • CC regulation better than ±5%
    • Power factor >0.9
    • High efficiency >93%
    • Critical Conduction Mode (CrM) buck, low EMI
    • Excellent line noise and transient rejection
  • Design Flexibility
    • Supports buck topology: high and low-side
    • Wide input and output voltage range operation
    • 3 family members cover power range for optimum device selection Highest Reliability
    • Lowest component count
    • Comprehensive protection features with auto-restart
    • Input and output overvoltage protection (OVP)
    • Output short-circuit protection
    • Open-loop protection
    • Advanced thermal control
    • Thermal foldback ensures that light continues to be delivered at elevated temperatures

Power Table

Output Power Table1
Product3 Optimized for Smallest Components
VOUT ≤ 30 V2 45 V ≤ VOUT ≤ 55 V2
LYT1402D 4.0 W 8.0 W
LYT1403D 7.5 W 15 W
LYT1404D 11 W 22 W
Product3 Optimized for Lowest THD
VOUT ≤ 30 V2 VOUT ≤ 55 V2
LYT1602D 4.0 W 8.0 W
LYT1603D 7.5 W 15 W
LYT1604D 11 W 22 W


  1. Maximum practical continuous power in an open frame design with adequate heat sinking, measured at 50°C ambient.
  2. Output power scales linearly if VOUT falls in between the specified voltages.
  3. Package: SO-8 (D Package).

Product Documents

Design Examples

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