参数资料
| 型号： | MIC2174-1YMM TR |
| 厂商： | Micrel Inc |
| 文件页数： | 13/27页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM 10-MSOP |
| 产品培训模块： | MIC2124 Synchronous Current Mode DC-DC Buck Controller |
| 标准包装： | 2,500 |
| 系列： | Hyper Speed Control™ |
| PWM 型： | 混合物 |
| 输出数： | 1 |
| 频率 - 最大： | 375kHz |
| 占空比： | 87% |
| 电源电压： | 3 V ~ 40 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 ~ 125°C |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 包装： | 带卷 (TR) |
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I CL ≈
Micrel, Inc.
The circuit in Figure 4 illustrates the MIC2174/MIC2174C
current limiting circuit.
Figure 4. MIC2174/MIC2174C Current Limiting Circuit
Using the typical V CL value of 130mV, the current limit
value is roughly estimated as:
130mV
R DS(ON)
For designs where the current ripple is significant
compared to the load current I OUT , or for low duty cycle
operation, calculating the current limit I CL should take
into account that one is sensing the peak inductor
current and that there is a blanking delay of
approximately 150ns.
MIC2174/MIC2174C
MOSFET Gate Drive
The MIC2174/MIC2174C high-side drive circuit is
designed to switch an N-Channel MOSFET. The block
diagram of Figure 1 shows a bootstrap circuit, consisting
of D1 (a Schottky diode is recommended) and C BST . This
circuit supplies energy to the high-side drive circuit.
Capacitor C BST is charged, while the low-side MOSFET
is on, and the voltage on the LX pin is approximately 0V.
When the high-side MOSFET driver is turned on, energy
from C BST is used to turn the MOSFET on. As the high-
side MOSFET turns on, the voltage on the LX pin
increases to approximately V HSD . Diode D1 is reversed
biased and C BST floats high while continuing to keep the
high-side MOSFET on. The bias current of the high-side
driver is less than 10mA so a 0.1 μ F to 1 μ F is sufficient to
hold the gate voltage with minimal droop for the power
stroke (high-side switching) cycle, i.e. Δ BST = 10mA x
3.33 μ s/0.1 μ F = 333mV. When the low-side MOSFET is
turned back on, C BST is recharged through D1. A small
resistor R G , which is in series with C BST , can be used to
slow down the turn-on time of the high-side N-channel
MOSFET.
The drive voltage is derived from the supply voltage V IN .
The nominal low-side gate drive voltage is V IN and the
nominal high-side gate drive voltage is approximately V IN
– V DIODE , where V DIODE is the voltage drop across D1. An
approximate 30ns delay between the high-side and low-
side driver transitions is used to prevent current from
simultaneously flowing unimpeded through both
MOSFETs.
V × t DLY
I CL =
130mV
R DS(ON)
+ OUT
L
?
Δ I L(pp)
2
(3)
Δ I L(pp) =
V OUT × (1 ? D)
f SW × L
(4)
where:
V OUT = The output voltage
t DLY = Current limit blanking time, 150ns typical
Δ I L(pp) = Inductor current ripple peak-to-peak value
D = Duty Cycle
f SW = Switching frequency
The MOSFET R DS(ON) varies 30 to 40% with temperature.
Therefore, it is recommended to add 50% margin to I CL
in the above equation to avoid false current limiting due
to an increased MOSFET junction temperature rise. It is
also recommended to connect the LX pin directly to the
drain of the low-side MOSFET to accurately sense the
MOSFETs R DS(ON) .
September 2010
13
M9999-091310-C
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC2174C | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:Synchronous Buck Controller Featuring Adaptive On-Time Control 40V Input, 300kHz |
| MIC2174C-1YMM | 功能描述:DC/DC 开关控制器 Low Cost 40V Synchronous Buck Controller 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 |
| MIC2174C-1YMM TR | 功能描述:DC/DC 开关控制器 Low Cost 40V Synchronous Buck Controller 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 |
| MIC2176-1 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:Wide Input Voltage, Synchronous Buck Controllers Featuring Adaptive On-Time Control |
| MIC2176-1YMM | 功能描述:DC/DC 开关控制器 76V Synchronous Buck Controller 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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