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Negative Output Flyback Pulse Width Modulator


Package | PIN: D | 8
Temp: I (-40 to 85)
Carrier: Partial Tube
Qty Price
1-9 $3.31
10-24 $2.98
25-99 $2.77
100-249 $2.43
250-499 $2.28
500-749 $1.94
750-999 $1.63
1000+ $1.56


  • 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

Texas Instruments  UC2572D

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.