參數(shù)資料
型號: UC1874
廠商: Texas Instruments, Inc.
英文描述: High Efficiency, Synchronous, Step-down (Buck) Controllers
中文描述: 高效率,同步,降壓(降壓)控制器
文件頁數(shù): 6/10頁
文件大?。?/td> 350K
代理商: UC1874
6
UC1874-1,-2
UC2874-1,-2
UC3874-1,-2
VREF:
VREF is the output of the precision reference.
The output is capable of supplying 20mA to peripheral
circuitry and is internally short circuit current limited.
VREF is disabled and low whenever VCC is below the
UVLO threshold, and when SS is pulled below 0.5V. A
VREF “good” comparator senses VREF and disables the
PWM stage until VREF has attained approximately 90%
of its nominal value. Bypass VREF to GND with a 0.1mF
ceramic capacitor for best performance.
VSNS:
This pin is the inverting input of the voltage ampli-
fier and serves as the output voltage feedback point for
the synchronous regulator. It senses the output voltage
through a voltage divider which produces a nominal 2.0V.
OPERATION: Refer to 5V, 25W Application Schematic
The UC3874 employs a fixed frequency average current
mode control buck topology to convert a higher battery
voltage down to a tightly regulated output voltage.
cial design techniques allow this bipolar IC to deliver ex-
ceptional performance while consuming approximately
6mA of supply current over an input voltage range of 4.5
to 35 volts. Fixed frequency operation allows synchroni-
zation to an existing system clock, and easier filtering.
Average current mode control provides inherent slope
compensation and accurate short circuit current limiting.
An additional benefit is its ability to maintain a constant
regulator gain regardless of whether the inductor current
is continuous or discontinuous.
Spe-
The output inductor current is sensed by an external low
value shunt resistor (Rsense).
current should be no larger than 100mV in order to mini-
mize sensing losses. The differential voltage across
Rsense is amplified by the internal X10 instrumentation
amplifier. The common mode input range for this ampli-
fier extends from GND to VCC in order to maintain accu-
rate current sensing under normal conditions as well as
abnormal conditions such as output short circuit and low
drop out (LDO) modes. The output of the X10 instrumen-
tation amplifier is applied to the inverting input of the cur-
rent
amplifier
through
an
converter’s output voltage feedback is applied to the
This signal at full load
external
resistor.
The
APPLICATION DIAGRAM
UDG-95006-1
相關PDF資料
PDF描述
UC1874-1 High Efficiency, Synchronous, Step-down (Buck) Controllers
UC1874-2 High Efficiency, Synchronous, Step-down (Buck) Controllers
UC1874-x High Efficiency, Synchronous, Step-down (Buck) Controllers
UC3874L-2 High Efficiency, Synchronous, Step-down Buck Controllers
UC3874 High Efficiency, Synchronous, Step-down (Buck) Controllers
相關代理商/技術參數(shù)
參數(shù)描述
UC1874-1 制造商:TI 制造商全稱:Texas Instruments 功能描述:High Efficiency, Synchronous, Step-down (Buck) Controllers
UC1874-2 制造商:TI 制造商全稱:Texas Instruments 功能描述:High Efficiency, Synchronous, Step-down (Buck) Controllers
UC1874DW-1 制造商:TI 制造商全稱:Texas Instruments 功能描述:High Efficiency, Synchronous, Step-down Buck Controllers
UC1874DW-2 制造商:TI 制造商全稱:Texas Instruments 功能描述:High Efficiency, Synchronous, Step-down Buck Controllers
UC1874DWTR-1 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC