参数资料
| 型号： | TPS51217DSCR |
| 厂商： | Texas Instruments |
| 文件页数： | 13/29页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM 10-SON |
| 标准包装： | 1 |
| 系列： | D-CAP™ |
| PWM 型： | 控制器 |
| 输出数： | 1 |
| 频率 - 最大： | 368kHz |
| 占空比： | 89% |
| 电源电压： | 4.5 V ~ 6.5 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 10-WFDFN 裸露焊盘 |
| 包装： | 标准包装 |
| 其它名称： | 296-28856-6 |
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SLUS947B – JUNE 2009 – REVISED APRIL 2012
SMALL SIGNAL MODEL
From small-signal loop analysis, a buck converter using D-CAP? mode can be simplified as shown in Figure 21 .
Switching Modulator
V IN
R1
V FB
PWM
Control
DRVH
L
V OUT
Logic
R2
+
+
and
Driver
DRVL
I IND
I C
I OUT
0.6 V
ESR
Voltage Divider
V C
R L
C O
Output
Capacitor
UDG-09063
Figure 21. Simplified Modulator Model
The output voltage is compared with internal reference voltage (ramp signal is ignored here for simplicity). The
PWM comparator determines the timing to turn on the high-side MOSFET. The gain and speed of the
comparator can be assumed high enough to keep the voltage at the beginning of each on cycle substantially
constant.
H(s) =
1
s ′ ESR ′ C O
(1)
For loop stability, the 0-dB frequency, ? 0 , defined in Equation 2 need to be lower than 1/4 of the switching
frequency.
￡ SW
f 0 =
1
2 p ′ ESR ′ C O
f
4
(2)
According to Equation 2 , the loop stability of D-CAP? mode modulator is mainly determined by the capacitor's
chemistry. For example, specialty polymer capacitors (SP-CAP) have C O on the order of several 100 μ F and
ESR in range of 10 m ? . These makes f 0 on the order of 100 kHz or less and the loop is stable. However,
ceramic capacitors have an ? 0 of more than 700 kHz, which is not suitable for this modulator.
RAMP SIGNAL
The TPS51217 adds a ramp signal to the 0.6-V reference in order to improve its jitter performance. As described
in the previous section, the feedback voltage is compared with the reference information to keep the output
voltage in regulation. By adding a small ramp signal to the reference, the S/N ratio at the onset of a new
switching cycle is improved. Therefore the operation becomes less jittery and more stable. The ramp signal is
controlled to start with –6 mV at the beginning of ON-cycle and becomes 0 mV at the end of OFF-cycle in
continuous conduction steady state.
Copyright ? 2009–2012, Texas Instruments Incorporated
13
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相关代理商/技术参数 |
参数描述 |
|---|---|
| TPS51217DSCT | 功能描述:DC/DC 开关控制器 3-28V Input 20A Synch St Down 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 |
| TPS51217EVM-533 | 功能描述:电源管理IC开发工具 TPS51217 Eval Module 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 |
| TPS51218 | 制造商:TI 制造商全称:Texas Instruments 功能描述:HIGH PERFORMANCE, SINGLE SYNCHRONOUS STEP-DOWN CONTROLLER FOR NOTEBOOK POWER SUPPLY |
| TPS51218DSCR | 功能描述:DC/DC 开关控制器 3-28V In,20A Synch Step Down 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 |
| TPS51218DSCT | 功能描述:DC/DC 开关控制器 3-28V In,20A Synch Step Down 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 |
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