UC3572 Negative Output Flyback Pulse Width Modulator | TI.com

UC3572 (ACTIVE)

Negative Output Flyback Pulse Width Modulator

Negative Output Flyback Pulse Width Modulator - UC3572
Datasheet
 

Description

The UC3572 is a negative output flyback pulse width modulator which converts a positive input voltage to a regulated negative output voltage. The chip is optimized for use in a single inductor negative flyback switching converter employing an external PMOS switch. The block diagram consists of a precision reference, an error amplifier configured for voltage mode operation, an oscillator, a PWM comparator with latching logic, and a 0.5A peak gate driver. The UC3572 includes an undervoltage lockout circuit to insure sufficient input supply voltage is present before any switching activity can occur, and a pulse-by-pulse current limit. Output current can be sensed and limited to a user determined maximum value. The UVLO circuit turns the chip off when the input voltage is below the UVLO threshold. In addition, a sleep comparator interfaces to the UVLO circuit to turn the chip off. This reduces the supply current to only 50uA, making the UC3572 ideal for battery powered applications.

Features

  • Simple Single Inductor Flyback PWM for Negative Voltage Generation
  • Drives External PMOS Switch
  • Contains UVLO Circuit
  • Includes Pulse-by-Pulse Current Limit
  • Low 50uA Sleep Mode Current

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Parametrics Compare all products in Buck-boost & inverting controllers (external switch)

 
Topology
Vin (Min) (V)
Vin (Max) (V)
Vout (Min) (V)
Vout (Max) (V)
Duty cycle (Max) (%)
Switching Frequency (Min) (kHz)
Switching Frequency (Max) (kHz)
Iq (Typ) (mA)
Features
Iout (Max) (A)
Operating temperature range (C)
Rating
Package Group
UC2572
Inverting    
4.2    
35    
-70    
-1    
100    
10    
200    
9    
   
10    
-40 to 85    
Catalog    
SOIC | 8