Single-Stage LED Driver IC with Combined PFC and
Constant Current Output for Buck Topology
Single-Stage PFC + Accurate CC Output
• ±3% CC regulation in single line input voltage applications
• Power factor >0.9
• High efficiency >93%
• Robust 725 V MOSFET for increased line voltage surge performance
• Critical Conduction Mode (CrM) buck
• Low EMI
• Excellent line noise and transient rejection
• Supports high- and low-side buck topologies
• Wide input (90 VAC – 308 VAC) and output voltage range operation
• 3 family members cover power range for optimum device selection
• Requires no inductor bias winding
• 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
• Over-temperature shutdown provides protection during fault
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
The CrM operation results in low turn-on losses and reduces cost of
output diode (slower reverse recovery).
LYTSwitch-1 devices are suitable for applications from 2 W to 22 W.
See Table 1 for selection guidance.
Figure 2. SO-8 D Package.
Figure 1a. High-Side Buck − Typical Application Schematic.
Figure 1b. Low-Side Buck − Typical Application Schematic.
Output Power Table1
Optimized for Smallest Components
VOUT ≤ 30 V2
45 V ≤ VOUT ≤ 55 V2
Optimized for Lowest THD
VOUT ≤ 30 V2
VOUT ≥ 55 V2
Table 1. Output Power Table (Buck Topology).
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).
This Product is Covered by Patents and/or Pending Patent Applications.