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参数资料
| 型号： | TPS40304ADRCT |
| 厂商： | TEXAS INSTRUMENTS INC |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING CONTROLLER, PQCC10 |
| 封装： | 3 X 3 MM, GREEN, PLASTIC, SON-10 |
| 文件页数： | 3/20页 |
| 文件大小： | 508K |
| 代理商： | TPS40304ADRCT |
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SLUSA30 – FEBRUARY 2010
Soft-Start Time
The soft-start time of the TPS40304A is user programmable by selecting a single capacitor. The EN/SS pin
sources 10 A to charge this capacitor. The actual output ramp-up time is the amount of time that it takes for the
10 A to charge the capacitor through a 591-mV range. There is some initial lag due to calibration and an offset
(800 mV) from the actual EN/SS pin voltage to the voltage applied to the error amplifier.
The soft-start is done in a closed loop fashion, meaning that the error amplifier controls the output voltage at all
times during the soft start period and the feedback loop is never open as occurs in duty cycle limit soft-start
schemes. The error amplifier has two non-inverting inputs, one connected to the 591-mV reference voltage, and
the other connected to the offset EN/SS pin voltage. The lower of these two voltages is what the error amplifier
controls the FB pin to. As the voltage on the EN/SS pin ramps up past approximately 1.4 V (800 mV offset
voltage plus the 591-mV reference voltage), the 591-mV reference voltage becomes the dominant input and the
converter has reached its final regulation voltage.
The capacitor required for a given soft-start ramp time for the output voltage is given by Equation 1.
where
CSS is the required capacitance on the EN/SS pin (F)
ISS is the soft-start source current (10 A)
VFB is the feedback reference voltage (591 mV)
tSS is the desired soft-start ramp time (s)
(1)
Oscillator and Frequency Spread Spectrum (FSS)
The oscillator frequency is internally fixed at 600 kHz.
Connecting a resistor with a value of 267 k
Ω ± 10% from BP to EN/SS enables the FSS feature. When enabled,
it spreads the internal oscillator frequency over a minimum 12% window using a 25-kHz modulation frequency
with triangular profile. By modulating the switching frequency, side-bands are created. The emission power of the
fundamental switching frequency and its harmonics is distributed into smaller pieces scattered around many
side-band frequencies. The effect significantly reduces the peak EMI noise and makes it much easier for the
resultant emission spectrum to pass EMI regulations.
Overcurrent Protection
Programmable OCP level at LDRV is from 6 mV to 150 mV at room temperature with 3000 ppm temperature
coefficient to help compensate for changes in the low-side FET channel resistance as temperature increases.
With a scale factor of 2, the actual trip point across the low-side FET is in the range of 12 mV to 300 mV. The
accuracy of the internal current source is ±5%. Overall offset voltage, including the offset voltage of the internal
comparator and the amplifier for scale factor of 2, is limited to ±8 mV.
Maximum clamp voltage at LDRV is 340 mV to avoid turning on the low-side FET during calibration and in a
pre-biased condition. The maximum clamp voltage is fixed and it does not change with temperature. If the
voltage drop across ROCSET reaches the 340 mV maximum clamp voltage during calibration (No ROCSET resistor
included), it disables OCP. Once disabled, there is no low-side or high-side current sensing.
OCP level at HDRV is fixed at 450 mV with 3000 ppm temperature coefficient to help compensate for changes in
the high-side FET channel resistance as temperature increases. OCP at HDRV provides pulse-by-pulse current
limiting.
Copyright 2010, Texas Instruments Incorporated
11
Product Folder Link(s) :TPS40304A
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| TPS40304DRCR | 功能描述:DC/DC 开关控制器 3-20V Wide Input Synch Buck Cntrlr 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 |
| TPS40304DRCT | 功能描述:DC/DC 开关控制器 3-20V Wide Input Synch Buck Cntrlr 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 |
| TPS40304DRCT | 制造商:Texas Instruments 功能描述:Synchronous Buck Controller IC 制造商:Texas Instruments 功能描述:IC, SYNC BUCK CONTROLLER, SON-10 |
| TPS40304EVM-353 | 功能描述:电源管理IC开发工具 Eval with NexFET Pwr MOSFETs RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| TPS40305 | 制造商:TI 制造商全称:Texas Instruments 功能描述:3-V TO 20-V INPUT SYNCHRONOUS BUCK CONTROLLER |
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