RT8480高压升压/SEPIC控制器及应用电路

立琦推出RT8480高压升压/SEPIC控制器

The RT8480 is a current mode PWM controller designed to drive an external MOSFET for high current LED applications. With a low side current sense amplifier threshold of 190mV, the LED current is programmable with one external current sense resistor. With programmable operating frequency up to 800kHz, the external inductor and capacitors can be small while maintaining high frequency. Dimming can be done by either analog or digital. A built-in clamping comparator and filter allow easy low noise analog dimming conversion from digital signal with only one external capacitor. An unique True PWM dimming control is made easy with MOSFET under LED string. A very high dimming ratio can be achieved by adopting both analog/digital dimming and True PWM dimming together. The RT8480 is available in a SOP-16 package.

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Ordering Info

Note : Richtek Green products are : ►RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. ►Suitable for use in SnPb or Pb-free soldering processes.

Features

• High Voltage Capability : VIN Up to 36V, VOUT is limited by External MOSFET Switch • Boost Operation • Current Mode PWM with Programmable Switching Frequency • Easy Dimming Control : Analog or Digital Converting to Analog with One External Capacitor • True PWM Dimming : External FET Driver is Build-In • Programmable Soft-Start to Avoid Inrush Current • Programmable Over Voltage Protection • VIN Undervoltage Lockout and Thermal Shutdown • 16-Lead SOP Package • RoHS Compliant and Halogen Free

Application

• General Industrial High Power LED Lighting • Desk Lights and Room Lighting • Building and Street Lighting • Industrial Display Backlight

Pin Configurations

( VIEW) SOP-16

RT8480应用电路 Typical Applications Circuit

Figure 1. Analog Dimming in Boost Configuration Figure 2. PWM to Analog Dimming in Boost Configuration Figure 3. True PWM Dimming in Boost Configuration Figure 4. Constant Voltage Output of Boost Converter Figure 5. Constant Voltage Output of SEPIC Converter