LYTSwitch-7

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

Figure 1. Buck − Typical Application Schematic.

Data Sheets

Product Details

The LYTSwitch™-7 family is ideal for single-stage, high PF, constant current LED dimmable applications.

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

LYTSwitch-7 devices are suitable for applications from 4 W to 22 W. See Graph 1 for selection guidance based on typical inductance. LYTSwitch-7 peak current mode operation is suitable for TRIAC applications without the need of an active bleeder.

Product Highlights

Single-Stage PFC + Accurate CC Output

  • ±3% CC regulation in single line input voltage applications
  • Power factor >0.9
  • High efficiency >85%
  • Robust 725 V MOSFET for increased line voltage surge performance
  • Critical Conduction Mode (CrM) buck
  • Low EMI
  • Excellent line noise and transient rejection

Dimming Highlights

  • Fast turn-on (<500 ms)
  • Low pop-on
  • Better than 10:1 dimming ratio
  • Simple passive R-C damper
  • Monotonic dimming response

Design Flexibility

  • Wide input (90 VAC – 308 VAC) and output voltage range operation
  • LYT7503D and LYT7504D both cover power range for optimum device selection
  • Requires no inductor bias winding
  • Small form factor package – SO-8

Highest Reliability

  • Industries lowest component count dimming solution
  • 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
    • Over-temperature shutdown provides protection during fault conditions

Applications

Output Power Graphs


Notes:

  1. Maximum practical continuous power in an open frame design with adequate heat sinking, measured at 50˚C ambient.
  2. Output power graph based on typical value in inductance, ILIMIT(AR), T ON(MAX) and package thermal limitations.

Product Documents

Design Examples

Product Image