Thursday, May 9, 2013

Telecom Server AC/DC Supply: Dual Controller: Analog

Block diagram (SBD) Server AC/DC Power Supply and Telecom Rectifier using TI’s Analog PFC and PWM controllers, High performance drivers and transceivers.

 Design Considerations

The challenges faced by AC/DC power supply developers today are achieving high power factor, low THD, and high efficiency across line and load conditions, high power density or reduced size, high reliability, and low system cost. Advanced power topologies such as interleaved PFC, bridgeless PFC, phase-shifted full-bridge DC/DC, LLC resonant DC/DC, and ZVS PWM DC/DC are commonly employed in today's designs addressing these needs. Most AC/DC power supplies use dual PWM controllers, a PFC controller and a DC/DC controller.
TI's Continuous Conduction Mode PFC controller achieves CCM control with fewer circuit components reducing BOM cost. Interleaved PFC controllers cater well for higher power and higher density form factor applications. The interleaving offers both input and output ripple current cancellation allowing smaller EMI filter, boost inductor and bulk capacitor.
TI's PWM DC/DC controller portfolio includes controllers for the Flyback, LLC Resonant Bridge, Phase Shifted Full Bridge, and Active Clamp Forward Topologies commonly found in server AC/DC designs. The Flyback controller uses a frequency modulation scheme that optimizes efficiency across the output power range while also providing unmatched 125mW no load power consumption. The LLC resonant half bridge controller offers 'zero voltage switching' ZVS of the power MOSFETs, a bounded operating frequency range and minimal external components improving both efficiency and overall system cost. The Active clamp forward controller family offers improved efficiency over single switch forward converters by both reducing the stress and allowing a lower voltage main switch MOSFET and by using the active clamp to recycle the magnetizing energy of the main transformer. The Phase shifted full bridge controller remains to be the industry's controller of choice for higher power applications as it offers ZVS and other features that helps reduce stress of MOSFETs and increase efficiency.
The family of UCC27xxx MOSFET drives includes a complete range of single and dual low-side MOSFET drivers ranging from 2A to 9A sink and source. They are available in complimentary, inverted and non-inverted varieties.
TI's Integrated Hot Swap Power Controllers are optimized for nominal -48V systems. The devices provide load current slew rate control and peak magnitude limiting.
Most of the Hot Swap Controllers have digital interface for precise programming and monitoring and also have Power good and fault outputs.
Other high-performance analog parts are also available to provide critical system functions and features such as sensor feedback, isolation, communication transceivers. (Telecom Server AC/DC Supply: Dual Controller: Analog)

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