参数资料
型号: TPS40074RHL
厂商: TEXAS INSTRUMENTS INC
元件分类: 稳压器
英文描述: 2 A SWITCHING CONTROLLER, 550 kHz SWITCHING FREQ-MAX, PQCC20
封装: PLASTIC, QFN-20
文件页数: 36/37页
文件大小: 448K
代理商: TPS40074RHL
www.ti.com
APPLICATION INFORMATION
MINIMUM PULSE WIDTH
SLEW RATE LIMIT ON VDD
13
7
14
12
10
8
ILIM
HDRV
SW
LDRV
VDD
PGND
TPS40074
C
R
VIN
UDG05058
+_
TPS40074
SLUS617–APRIL 2005
The TPS40074 allows the user to construct synchronous voltage mode buck converters with inputs ranging from
4.5 V to 28 V and outputs as low as 700 mV. Predictive gate drive circuitry optimizes switching delays for
increased efficiency and improved converter output power capability. Voltage feed-forward is employed to ease
loop compensation for wide input range designs and provide better line transient response.
An on-board unity gain differential amplifier is provided for remote sensing in applications that require the tightest
load regulation. The TPS40074 incorporates circuitry to allow startup into a pre-existing output voltage without
sinking current from the source of the pre-existing output voltage. This avoids damaging sensitive loads at
startup. The controller can be synchronized to an external clock source or can free run at a user programmable
frequency. An integrated power good indicator is available for logic (open drain) output of the condition of the
output of the converter.
The TPS40074 has limitations on the minimum pulse width that can be used to design a converter. Reliable
operation is guaranteed for nominal pulse widths of 150 ns and above. This places some restrictions on the
conversion ratio that can be achieved at a given switching frequency. Figure 2 shows minimum output voltage for
a given input voltage and frequency.
The regulator that supplies power for the drivers on the TPS40074 requires a limited rising slew rate on VDD for
proper operation if the input voltage is above 10 V. If the slew rate is too great, this regulator can over shoot and
damage to the part can occur. To ensure that the part operates properly, limit the slew rate to no more than
0.12 V/s as the voltage at VDD crosses 8 V. If necessary, an R-C filter can be used on the VDD pin of the
device. Connect the resistor from the VDD pin to the input supply of the converter. Connect the capacitor from
the VDD pin to PGND. There should not be excessive (more than a 200-mV) voltage drop across the resistor in
normal operation. This places some constraints on the R-C values that can be used. Figure 1 is a schematic
fragment that shows the connection of the R-C slew rate limit circuit. Equation 1 and Equation 2 give values for R
and C that limits the slew rate in the worst case condition.
Figure 1. Limiting the Slew Rate
8
相关PDF资料
PDF描述
TPS40075RHLR 2 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PQCC20
TPS40075RHLTG4 2 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PQCC20
TPS40077PWPR 2 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16
TPS40077PWPRG4 2 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16
TPS40077PWPG4 2 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16
相关代理商/技术参数
参数描述
TPS40074RHLR 功能描述:DC/DC 开关控制器 Mid Input Sync Buck w/Vltg Feed-Fwd RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
TPS40074RHLRG4 功能描述:DC/DC 开关控制器 Mid Input Sync Buck w/Vltg Feed-Fwd RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
TPS40074RHLT 功能描述:DC/DC 开关控制器 Mid Input Sync Buck w/Vltg Feed-Fwd RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
TPS40074RHLTG4 功能描述:DC/DC 开关控制器 Mid Input Sync Buck w/Vltg Feed-Fwd RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
TPS40075 制造商:TI 制造商全称:Texas Instruments 功能描述:4.5V TO 18V INPUT 10 PIN SYNCHRONOUS BUCK CONTROLLER WITH POWER GOOD