New Industry Products

16Vin to 600Vin No-Opto Isolated Flyback Controller Delivers up to 100W

July 24, 2019 by Scott McMahan

The LT8316 from Analog Devices solves key electric vehicle battery problems, including high voltage power conversion, isolation from the battery stack (safety), and high-efficiency power conversion to minimize battery drain. The LT8316 is a controller that also allows the optimization of power needs from selecting the power switch that best fits the application.

Applications for this flyback controller include isolated telecom, automotive, industrial, and medical power supplies, isolated offline housekeeping power supplies, electric vehicles, and battery stacks. (See typical application diagram above).

The device features a 16V to 600V input voltage range that allows for isolated power at high input voltages. It has a 75µA quiescent current for extremely low standby power that minimizes battery drain and helps maintain output accuracy.

With no-opto flyback, it regulates the output from the primary side by measuring the reflected voltage, thereby eliminating the need for an optocoupler, which would increase cost and size.

No optoisolator is required for regulation. The device samples the output voltage from the isolated flyback waveform that appears across a third winding on the transformer.

Quasi-resonant boundary mode operation enhances load regulation, reduces transformer size, and preserves high efficiency.

At start-up, the LT8316 charges its INTVCC capacitor from a high voltage current source. During regular operation, the current source turns off, and the device draws power from a third winding on the transformer, thereby minimizing standby power dissipation.

Operating from a wide range of input supply voltages, the LT8316 can deliver up to 100W of power. It is available in a thermally enhanced 20-pin TSSOP package with four pins removed for high voltage spacing.


  • Wide Input Voltage Range: 16V to 600V
  • 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