CL88030 230 V
AC
Offline LED Driver Evaluation Board User’s Guide
DS50002772A-page 10
2018 Microchip Technology Inc.
• Reduced Output Ripple (optional):
- An external capacitor with four diodes provides lower output ripple
- Strobing occurs at low line
- Provides continuous power to the driver
• Active Line Regulation:
- Active circuitry provides better regulated output power over variations in AC
line voltage
- –12%/+0% line regulation typical
- Prevents driver from overheating at high AC line voltages
- Prevents excessive currents at low line
- Required for reasonable line regulation and efficient operation, given only four
or six taps
- If unused, the ALR pin is left open in the application
• Overtemperature Protection (OTP), Optional:
- An inexpensive external NTC thermistor provides remote temperature
sensing. The thermistor may be near the LEDs to provide nearly direct
monitoring of LED temperature.
- OTP is linear (no on/off cycling)
- A widely available, 470 k
NTC provides an 85°C maximum temperature
- Temperature adjustable via selection of NTC thermistor resistance
- If unused, the OTP pin is tied to BIAS
• Two Current-setting Resistors:
- Different hold-up and direct AC currents lower the THD and output ripple
- Tap current ratios internally set
- Reduces component count
- Fewer pins
- Simplifies application design
- Single-point current control for reduced EMI
