参数资料
| 型号： | MIC2169BYMME |
| 厂商： | Micrel Inc |
| 文件页数： | 14/25页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 10-MSOP |
| 特色产品： | MIC2169B Buck Control IC |
| 标准包装： | 100 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 550kHz |
| 占空比： | 92% |
| 电源电压： | 3 V ~ 14.5 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-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 |
| 包装： | 管件 |
| 产品目录页面： | 1092 (CN2011-ZH PDF) |
| 其它名称： | 576-3545-5 |
f LC =
? ( 1 + ESR × s × C ) ?
G ( s ) = ? 2 ?
f ZERO =
Micrel, Inc.
Depending on the circuit components and operating
conditions, an external Schottky diode will give a ?% to
1% improvement in efficiency.
Feedback Loop Compensation
The MIC2169B controller comes with an internal
transconductance error amplifier used for compensating
the voltage feedback loop by placing a capacitor (C1) in
series with a resistor (R1) and another capacitor C2 in
parallel from the COMP pin to ground. See “Functional
Block Diagram.”
Power Stage
The power stage of a voltage mode controller has an
inductor, L1, with its winding resistance (DCR)
connected to the output capacitor, C OUT , with its
electrical series resistance (ESR) as shown in Figure 7.
The transfer function G(s), for such a system is:
L DCR
V O
ESR
C OUT
Figure 7. The Output LC Filter in a Voltage-Mode Buck
Converter
? DCR × s × C + s × L × C + 1 + ESR × s × C ?
Plotting this transfer function with the following assumed
values (L=1 μ H, DCR=0.009 Ω , C OUT =660 μ F,
ESR=0.025 Ω ) gives lot of insight as to why one needs to
compensate the loop by adding resistor and capacitors
MIC2169B
Figure 9. Phase Curve for G(s)
It can be seen from the transfer function G(s) and the
gain curve that the output inductor and capacitor create
a two pole system with a break frequency at:
1
2 × π L × C OUT
Therefore, f LC = 6.2kHz
By looking at the phase curve, it can be seen that the
output capacitor ESR (0.025 Ω ) cancels one of the two
poles (LC OUT ) system by introducing a zero at:
1
2 × π × ESR × C OUT
Therefore, F ZERO = 9.6kHz.
From the point of view of compensating the voltage loop,
it is recommended to use higher ESR output capacitors
since they provide a 90° phase gain in the power path.
For comparison purposes, Figure 10, shows the same
phase curve with an ESR value of 0.002 Ω .
on the COMP pin. Figures 8 and 9 show the gain curve
and phase curve for the above transfer function.
Figure 10. The Phase Curve with ESR = 0.002 Ω
Figure 8. The Gain Curve for G(s)
April 2010
14
M9999-041210-B
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相关代理商/技术参数 |
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| MIC2169BYMME TR | 功能描述:直流/直流开关转换器 Synchronous Step Down Converter RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MIC2169MM | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:500 KHZ PWM SYNCHRONOUS BUCK CONTROL IC |
| MIC2169YMM | 功能描述:直流/直流开关调节器 Replaced by MIC2169AYMM (Lead Free) RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MIC2169YMM TR | 功能描述:直流/直流开关调节器 Replaced by MIC2169AYMM TR (Lead Free) RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MIC2171 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:100kHz 2.5A Switching Regulator Preliminary Information |
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