RT8452应用电路 (高电压高电流LED驱动器控制器) The RT8452 is a current mode PWM controller designed to drive an external MOSFET for high current LED applications. With a current sense amplifier threshold of 190mV, the LED current is programmable with one external current sense resistor. With the maximum operating input voltage of 36V and output voltage up to 48V, the RT8452 is ideal for buck, boost or buck-boost operation.
With 350kHz operating frequency, the external inductor and capacitors can be small while maintaining high efficiency.
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 RT8452 is available in WQFN-16L 3x3 and SOP-16 packages. 更详细介绍：http:///soft/39/2010/2010093090874.html |
| 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 : VINUp to 36V, VOUTUp to 48V
• Buck, Boost or Buck-Boost Operation
• Current Mode PWM with 350kHz Switching Frenquency
• 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
• VINUndervoltage Lockout and Thermal Shutdown
• 16-Lead WQFN and SOP Packages.
• 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
WQFN-16L 3x3 |
| 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. Analog Dimming in Buck-Boost Configuration
 Figure 5. Analog Dimming in Buck Configuration |
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