Demonstration circuit 2718A from Analog Devices is a non-opto flyback dc-dc converter featuring the LT8316. The demo board outputs 12V and maintains tight regulation with a load current from 30mA to 3A. It is optimized to operate over a wide 100- to 600-Vdc input voltage range. Output voltage accuracy stays within ±5% over the entire input voltage and load range.
Possible applications for the 2718A include: Isolated telecom, automotive, industrial, medical power supplies; Isolated off-line housekeeping power supplies; Electric vehicles and battery stacks; and Multioutput isolated power supplies for inverter gate drives.
Features include:
- Wide Input Voltage Range: 100- to 600-Vdc
- No Opto-Isolator Required for Regulation
- Quasi-Resonant Boundary Mode Operation
- Constant-Current and Constant-Voltage Regulation
- Low-Ripple Light Load Burst Mode® Operation
- Low Quiescent Current: 75µA
- Programmable Current Limit and Soft-Start
- TSSOP Package with High-Voltage Spacing
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2718A performance summary. Specifications are at TA = 25°C. (click on table to enlarge)
2718A schematic. (click on schematic to enlarge)
The LT8316
The LT8316 is a high-voltage flyback controller. No optoisolator is needed for regulation. The part samples the output voltage from the isolated flyback waveform appearing across a third winding on the transformer. Quasi-resonant boundary mode operation improves load regulation. The LT8316 is available in a thermally-enhanced 20-pin TSSOP package with four pins removed for high-voltage spacing.
At start-up, the LT8316 charges its INTVCC capacitor via a high voltage current source. During normal operation, the current source turns off and the device draws its power from a third winding on the transformer minimizing standby power dissipation.
