UC2879

ACTIVE

Enhanced bipolar phase shifted full bridge controller with selectable UVLO, -40°C to 85°C

Product details

Vin (max) (V) 20 Operating temperature range (°C) -40 to 85 Control mode Current, Feedforward, Voltage Topology Phase-shifted full bridge Rating Catalog, Military Features Adjustable switching frequency, Current limiting, Error amplifier, Soft start, Soft switching, Synchronization pin Duty cycle (max) (%) 100
Vin (max) (V) 20 Operating temperature range (°C) -40 to 85 Control mode Current, Feedforward, Voltage Topology Phase-shifted full bridge Rating Catalog, Military Features Adjustable switching frequency, Current limiting, Error amplifier, Soft start, Soft switching, Synchronization pin Duty cycle (max) (%) 100
PDIP (N) 20 228.702 mm² 24.33 x 9.4 SOIC (DW) 20 131.84 mm² 12.8 x 10.3
  • Programmable Output Turn On Delay; Zero Delay Available
  • Compatible with Voltage Mode or Current Mode Topologies
  • Practical Operation at Switching Frequencies to 300 kHz
  • 10-MHz Error Amplifier
  • Pin Programmable Undervoltage Lockout
  • Low Startup Current — 150 µA
  • Soft Start Control
  • Outputs Active Low During UVLO

  • Programmable Output Turn On Delay; Zero Delay Available
  • Compatible with Voltage Mode or Current Mode Topologies
  • Practical Operation at Switching Frequencies to 300 kHz
  • 10-MHz Error Amplifier
  • Pin Programmable Undervoltage Lockout
  • Low Startup Current — 150 µA
  • Soft Start Control
  • Outputs Active Low During UVLO

The UC3879 controls a bridge power stage by phase shifting the switching of one half-bridge with respect to the other. This allows constant frequency pulse width modulation in combination with resonant, zero-voltage switching for high efficiency performance. The UC3879 can be configured to provide control in either voltage mode or current mode operation, with overcurrent shutdown for fast fault protection.

Independently programmable time delays provide dead-time at the turn-on of each output stage, allowing time for each resonant switching interval.

With the oscillator capable of operating in excess of 600 kHz, overall output switching frequencies to 300 kHz are practical. In addition to the standard free running mode, with the CLKSYNC pin, the user may configure the UC3879 to accept an external clock synchronization signal. Alternatively, up to three units can be locked together with the operational frequency determined by the fastest device.

Protective features include an undervoltage lockout and overcurrent protection. Additional features include a 10-MHz error amplifier, a 5-V precision reference, and soft start. The UC3879 is available in 20 pin N, J, DW, and Q and 28 pin L packages.

The UC3879 controls a bridge power stage by phase shifting the switching of one half-bridge with respect to the other. This allows constant frequency pulse width modulation in combination with resonant, zero-voltage switching for high efficiency performance. The UC3879 can be configured to provide control in either voltage mode or current mode operation, with overcurrent shutdown for fast fault protection.

Independently programmable time delays provide dead-time at the turn-on of each output stage, allowing time for each resonant switching interval.

With the oscillator capable of operating in excess of 600 kHz, overall output switching frequencies to 300 kHz are practical. In addition to the standard free running mode, with the CLKSYNC pin, the user may configure the UC3879 to accept an external clock synchronization signal. Alternatively, up to three units can be locked together with the operational frequency determined by the fastest device.

Protective features include an undervoltage lockout and overcurrent protection. Additional features include a 10-MHz error amplifier, a 5-V precision reference, and soft start. The UC3879 is available in 20 pin N, J, DW, and Q and 28 pin L packages.

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Technical documentation

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Type Title Date
* Data sheet Phase Shift Resonant Controller datasheet (Rev. B) 13 Dec 2006
Application note U-154 The New UC3879 Phase-Shifted PWM Controller Simplifies the Design 05 Sep 1999

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

UCC3895EVM-001 — UCC3895 Evaluation Module

The UCC3895EVM-001 is an isolated 48V input phase shifted full bridge converter providing an output of 3.3V at 15A. Using the AB outputs of the UCC3895, a novel technique for direct control driven synchronous rectification is demonstrated.

User guide: PDF
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Package Pins CAD symbols, footprints & 3D models
PDIP (N) 20 Ultra Librarian
SOIC (DW) 20 Ultra Librarian

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