Inicio Gestión de la energía Controladores CA/CC y CC/CC (FET externo)

UC3845

ACTIVO

Controlador PWM de 500 kHz y terminación única con modo de corriente, UVLO de 8.4 V/7.6 V, ciclo de

Detalles del producto

Vin (max) (V) 28 Operating temperature range (°C) 0 to 70 Control mode Peak current mode Topology Boost, Buck, Buck boost, Flyback, Forward Rating Catalog Features Adjustable switching frequency, Current limiting, Dead time control, Error amplifier, Fixed frequency, Multi-topology Duty cycle (max) (%) 50
Vin (max) (V) 28 Operating temperature range (°C) 0 to 70 Control mode Peak current mode Topology Boost, Buck, Buck boost, Flyback, Forward Rating Catalog Features Adjustable switching frequency, Current limiting, Dead time control, Error amplifier, Fixed frequency, Multi-topology Duty cycle (max) (%) 50
PDIP (P) 8 92.5083 mm² 9.81 x 9.43 SOIC (D) 8 29.4 mm² 4.9 x 6 SOIC (D) 14 51.9 mm² 8.65 x 6
  • Optimized for off-line and DC-to-DC converters
  • Low start-up current (< 1mA)
  • Automatic feedforward compensation
  • Pulse-by-pulse current limiting
  • Enhanced load-response characteristics
  • Undervoltage lockout with hysteresis
  • Double-pulse suppression
  • High-current totem-pole output
  • Internally trimmed bandgap reference
  • Up to 500kHz operation
  • Error amplifier with low output resistance
  • Optimized for off-line and DC-to-DC converters
  • Low start-up current (< 1mA)
  • Automatic feedforward compensation
  • Pulse-by-pulse current limiting
  • Enhanced load-response characteristics
  • Undervoltage lockout with hysteresis
  • Double-pulse suppression
  • High-current totem-pole output
  • Internally trimmed bandgap reference
  • Up to 500kHz operation
  • Error amplifier with low output resistance

The UCx84x series of control integrated circuits provide the features that are necessary to implement off-line or DC-to-DC fixed-frequency current-mode control schemes, with a minimum number of external components. The internally implemented circuits include an undervoltage lockout (UVLO), featuring a start-up current of less than 1mA, and a precision reference trimmed for accuracy at the error amplifier input. Other internal circuits include logic to provide latched operation, a pulse-width modulation (PWM) comparator that also provides current-limit control, and a totem-pole output stage that is designed to source or sink high-peak current. The output stage, designed for driving N-channel MOSFETs, is low when the output stage is in the off state.

The UCx84x family offers a variety of package options, temperature range options, choice of maximum duty cycle, and choice of turnon and turnoff thresholds and hysteresis ranges. Devices with higher turnon or turnoff hysteresis are good choices for off-line power supplies, while the devices with a narrower hysteresis range are designed for DC-DC applications. The UC184x devices are specified for operation from –55°C to 125°C, the UC284x series is specified for operation from –40°C to 85°C, and the UC384x series is specified for operation from 0°C to 70°C.

The UCx84x series of control integrated circuits provide the features that are necessary to implement off-line or DC-to-DC fixed-frequency current-mode control schemes, with a minimum number of external components. The internally implemented circuits include an undervoltage lockout (UVLO), featuring a start-up current of less than 1mA, and a precision reference trimmed for accuracy at the error amplifier input. Other internal circuits include logic to provide latched operation, a pulse-width modulation (PWM) comparator that also provides current-limit control, and a totem-pole output stage that is designed to source or sink high-peak current. The output stage, designed for driving N-channel MOSFETs, is low when the output stage is in the off state.

The UCx84x family offers a variety of package options, temperature range options, choice of maximum duty cycle, and choice of turnon and turnoff thresholds and hysteresis ranges. Devices with higher turnon or turnoff hysteresis are good choices for off-line power supplies, while the devices with a narrower hysteresis range are designed for DC-DC applications. The UC184x devices are specified for operation from –55°C to 125°C, the UC284x series is specified for operation from –40°C to 85°C, and the UC384x series is specified for operation from 0°C to 70°C.

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Documentación técnica

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* Data sheet UCx84x Current-Mode PWM Controllers datasheet (Rev. H) PDF | HTML 11 oct 2024
Application note Conditioning a Switch-mode Power Supply Current Signal Using TI Op Amps (Rev. A) PDF | HTML 11 jun 2021
Application note Understanding Inverting Buck-Boost Power Stages in Switch Mode Power Supplies (Rev. B) 12 mar 2019
Selection guide Power Management Guide 2018 (Rev. R) 25 jun 2018
Technical article When should you use PWM controllers? PDF | HTML 02 dic 2016
Application note UCC38C42 Family of High-Speed BiCMOS Current-Mode PWM Controllers 07 feb 2002
Application note DN-26 UC3842A Low-Cost Start-up and Fault Protection Circuit 05 sep 1999
Application note DN-27 UC1842/UC1842A Family - Summary of Functional Differences 05 sep 1999
Application note DN-40 The Effects of Oscillator Discharge Current Variations on Maximum Duty 05 sep 1999
Application note DN-42A Design Considerations for Transitioning from UC3842 to the New UCC3802 05 sep 1999
Application note DN-65 Considerations in Powering BiCMOS ICs 05 sep 1999
Application note U-100A UC3842/3/4/5 Provides Low-Cost Current-Mode Control 05 sep 1999
Application note U-111, Practical Considerations in Current Mode Power Supplies 05 sep 1999
Application note Understanding Boost Power Stages In Switchmode Power Supplies 04 mar 1999
Application note Understanding Buck Power Stages In Switchmode Power Supplies 04 mar 1999

Diseño y desarrollo

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Modelo de simulación

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Encapsulado Pines Símbolos CAD, huellas y modelos 3D
PDIP (P) 8 Ultra Librarian
SOIC (D) 8 Ultra Librarian
SOIC (D) 14 Ultra Librarian

Pedidos y calidad

Información incluida:
  • RoHS
  • REACH
  • Marcado del dispositivo
  • Acabado de plomo/material de la bola
  • Clasificación de nivel de sensibilidad a la humedad (MSL) / reflujo máximo
  • Estimaciones de tiempo medio entre fallas (MTBF)/fallas en el tiempo (FIT)
  • Contenido del material
  • Resumen de calificaciones
  • Monitoreo continuo de confiabilidad
Información incluida:
  • Lugar de fabricación
  • Lugar de ensamblaje

Soporte y capacitación

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