Isolated Flyback Converter without an Opto-Coupler
The LTR3575 is a monolithic switching regulator specifically designed for the isolated flyback topology. No third winding or optoisolator is required for regulaTIon. The part senses the isolated output voltage directly from the primary side flyback waveform. A 2.5A, 60V NPN power switch is integrated along with all control logic into a 16-lead TSSOP package.
The LT3575 operates with input supply voltages from 3V to 40V, and can deliver output power up to 14W with no external power switch. The LT3575 uTIlizes boundary mode operaTIon to provide a small magneTIc solution with improved load regulation.
The output voltage is easily set with two external resistors and the transformer turns ratio. Off the shelf transformers are available for many applications.
LT3575主要特性:
3V to 40V Input Voltage Range
2.5A, 60V Integrated NPN Power Switch
Boundary Mode Operation
No Transformer Third Winding or Optoisolator Required for Regulation
Improved Primary-Side Winding Feedback Load Regulation
VOUT Set with Two External Resistors
BIAS Pin for Internal Bias Supply and Power NPN Driver
Programmable Soft-Start
Programmable Power Switch Current Limit
Thermally Enhanced 16-Lead TSSOP
LT3575应用:
Industrial, Automotive and Medical Isolated Power Supplies
图1。LT3575方框图
图2。LT3575低输入电压5V隔离反激转换器电路图
图3。LT3575 +/-12V隔离反激转换器电路图
图4。LT3575 5V隔离反激转换器电路图
图5。LT3575 3.3V隔离反激转换器电路图
图6。LT3575 12V隔离反激转换器电路图
图7。LT3575 四输出12V隔离反激转换器电路图