器件名称: UC2573
功能描述: Buck Pulse Width Modulator Stepdown Voltage Regulator
文件大小: 136.6KB 共5页
简 介:UC1573 UC2573 UC3573
Buck Pulse Width Modulator Stepdown Voltage Regulator
FEATURES Simple Single Inductor Buck PWM Stepdown Voltage Regulation Drives External PMOS Switch Contains UVLO Circuit Includes Pulse-by-Pulse Current Limit Low 50A Sleep Mode Current
DESCRIPTION
The UC3573 is a Buck pulse width modulator which steps down and regulates a positive input voltage. The chip is optimized for use in a single inductor buck 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 UC3573 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. Input current can be sensed and limited to a user determined maximum value. In addition, a sleep comparator interfaces to the UVLO circuit which turns the chip off when the input voltage is below the UVLO threshold. This reduces the supply current to only 50A, making the UC3573 ideal for battery powered applications.
BLOCK DIAGRAM
UDG-94106-1
SLUS346 - APRIL 1999
ABSOLUTE MAXIMUM RATINGS
VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35V EAINV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.6V to VCC IEAOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . ……
