Texas Instruments' UCC28910 and UCC28911 are high-voltage flyback switches that provide output voltage and current regulation without the use of optocouplers. Both devices integrate a 700V power FET and controller that processes operational information from the flyback auxiliary winding and power FET to provide precise output voltage and current control. The integrated high-voltage current source for start-up is switched off during operation of the device, and the controller current consumption can be dynamically adjusted according to the load. Both can achieve very low standby power consumption.
The control algorithms in UCC28910 and UCC28911 combine switching frequency and peak primary current modulation, which can make the working efficiency meet or exceed applicable standards. Discontinuous Conduction Mode (DCM) with valley switching reduces switching losses. Built-in protection helps control stress levels of secondary and major components across the entire working range. The company said that frequency jitter can help reduce the cost of EMI filters.
