Current Mode PWM Controller - UC3846

UC3846 (ACTIVE)

Current Mode PWM Controller

 

Description

The UC1846/7 family of control devices provides all of the necessary features to implement fixed-frequency, current-mode control schemes while maintaining a minimum external parts count. The superior performance of this technique can be measured in improved line regulation, enhanced load response characteristics, and a simpler, easier-to-design control loop. Topological advantages include inherent pulse-by-pulse current limiting capability, automatic symmetry correction for push-pull converters, and the ability to parallel while maintaining equal current sharing. \

Protection circuitry includes built-in undervoltage lockout and programmable current limit, in addition to soft-start capability. A shutdown function is also available, which can initiate either a complete shutdown with automatic restart or latch the supply off.

Other features include fully-latched operation, double-pulse suppression, deadline adjust capability, and a ±1% trimmed band gap reference.

The UC1846 features low outputs in the OFF state, while the UCx847 features high outputs in the OFF state.

Features

  • Automatic Feedforward Compensation
  • Programmable Pulse-by-Pulse Current Limiting
  • Automatic Symmetry Correction in Push-Pull
    Configuration
  • Enhanced Load Response Characteristics
  • Parallel Operation Capability for Modular Power
    Systems
  • Differential Current Sense Amplifier with Wide
    Common Mode Range
  • Double-Pulse Suppression
  • 500-mA (Peak) Totem-pole Outputs
  • ±1% Band Gap Reference
  • Undervoltage Lockout
  • Soft-Start Capability
  • Shutdown Terminal
  • 500-kHz Operation

View more

Parametrics Compare all products in PWM and Resonant Controller

 
Topology
Control Method
Vin (Min) (V)
Vin (Max) (V)
Frequency (Max) (kHz)
UVLO Thresholds On/Off (V)
Duty Cycle (Max) (%)
Gate Drive (Typ) (A)
Special Features
Rating
Operating Temperature Range (C)
Pin/Package
Approx. Price (US$)
UC3846 UC1846 UC2846
Boost
Flyback
Forward
Half-Bridge
Push-Pull   
Boost
Flyback
Forward
Full-Bridge
Half-Bridge
Push-Pull   
Boost
Flyback
Forward
Full-Bridge
Half-Bridge
Push-Pull   
Current    Current    Current   
7    7    7.7   
40    40    40   
500    500    500   
7.7/6.95    7.7/6.95    7.7/6.95   
50    50    50   
0.5    0.5    0.5   
Error Amplifier
Multi-topology
Soft Start
Synchronization Pin   
Error Amplifier
Soft Start
Synchronization Pin
Multi-topology   
Error Amplifier
Multi-topology
Soft Start
Synchronization Pin   
Catalog    Military    Catalog   
0 to 70    -55 to 125    -40 to 85   
16PDIP
16SOIC
20PLCC   
16CDIP
20LCCC   
16PDIP
16SOIC
20PLCC   
1.39 | 1ku      1.39 | 1ku   

Other qualified versions of UC3846

Version Part Number Definition
Military UC1846 QML certified for Military and Defense Applications
Space UC1846-SP Radiation tolerant, ceramic packaging and qualified for use in Space-based application
Enhanced Product UC1846-EP Supports Defense, Aerospace and Medical Applications

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