Diodes – AP1688: Universal Input Voltage, High Power Factor and High Efficiency LED Buck Controller


The AP1688 is a high power factor, constant current buck controller for universal input voltage applications.
The buck controller operates under Boundary Conduction Mode (BCM) to achieve high efficiency, low electromagnetic interference (EMI) and low total harmonic distortion (THD). Open loop control is adopted for the AP1688, which achieves excellent line and load regulation. AP1688 features fast start-up, low start-up current, low operation current and high efficiency. It also has comprehensive protection features including undervoltage lockout (UVLO), over-voltage protection (OVP), overcurrent protection (OCP), over-protection (OTP) and LED short and open protection.


  • Optimized for buck topology
  • >0.9 high power factor
  • ±5% system current accuracy
  • Low start-up current
  • Eliminates control loop compensation circuitry
  • Open load and reload detection
  • BCM operation
  • >90% high efficiency
  • Good line regulation and load regulation
  • Tight CC regulation performance
  • Built-in acceleration start