- 您现在的位置：买卖IC网 > PDF目录15356 > MIC2176-2YMM TR (Micrel Inc)IC REG CTRLR BUCK PWM 10-MSOP PDF资料下载
参数资料
| 型号： | MIC2176-2YMM TR |
| 厂商： | Micrel Inc |
| 文件页数： | 15/31页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM 10-MSOP |
| 标准包装： | 2,500 |
| 系列： | Hyper Speed Control™ |
| PWM 型： | 混合物 |
| 输出数： | 1 |
| 频率 - 最大： | 250kHz |
| 占空比： | 93% |
| 电源电压： | 4.5 V ~ 75 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) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页当前第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页
Micrel, Inc.
Figure 3 shows the operation of the MIC2176 during a
load transient. The output voltage drops due to the
sudden load increase, which causes the V FB to be less
than V REF . This will cause the error comparator to trigger
an ON-time period. At the end of the ON-time period, a
minimum OFF-time t OFF(min) is generated to charge C BST
since the feedback voltage is still below V REF . Then, the
next ON-time period is triggered due to the low feedback
voltage. Therefore, the switching frequency changes
during the load transient, but returns to the nominal fixed
frequency once the output has stabilized at the new load
current level. With the varying duty cycle and switching
frequency, the output recovery time is fast and the
output voltage deviation is small in MIC2176 converter.
Figure 3. MIC2176 Load Transient Response
Unlike true current-mode control, the MIC2176 uses the
output voltage ripple to trigger an ON-time period. The
output voltage ripple is proportional to the inductor
current ripple if the ESR of the output capacitor is large
enough. The MIC2176 control loop has the advantage of
eliminating the need for slope compensation.
In order to meet the stability requirements, the MIC2176
feedback voltage ripple should be in phase with the
inductor current ripple and large enough to be sensed by
MIC2176
Soft-Start
Soft-start reduces the power supply input surge current
at startup by controlling the output voltage rise time. The
input surge appears while the output capacitor is
charged up. A slower output rise time will draw a lower
input surge current.
The MIC2176 implements an internal digital soft-start by
making the 0.8V reference voltage V REF ramp from 0 to
100% in about 6ms with 9.7mV steps. Therefore, the
output voltage is controlled to increase slowly by a stair-
case V FB ramp. Once the soft-start cycle ends, the
related circuitry is disabled to reduce current
consumption. V DD must be powered up at the same time
or after V IN to make the soft-start function correctly.
Current Limit
The MIC2176 uses the R DS(ON) of the low-side power
MOSFET to sense over-current conditions. This method
will avoid adding cost, board space and power losses
taken by discrete current sense resistors. The low-side
MOSFET is used because it displays much lower
parasitic oscillations during switching than the high-side
MOSFET.
In each switching cycle of the MIC2176 converter, the
inductor current is sensed by monitoring the low-side
MOSFET in the OFF period. The sensed voltage is
compared with a current-limit threshold voltage V CL after
a blanking time of 150ns. If the sensed voltage is over
V CL , which is 133mV typical at 0.8V V FB , then the
MIC2176 turns off the high-side and low-side MOSFETs
and a soft-start sequence is triggered. This mode of
operation is called “hiccup mode” and its purpose is to
protect the downstream load in case of a hard short. The
current limit threshold V CL has a foldback characteristic
related to the FB voltage. Please refer to the “Typical
Characteristics” for the curve of current limit threshold vs.
FB voltage percentage. The circuit in Figure 4 illustrates
the MIC2176 current limiting circuit.
the g m amplifier and the error comparator. The
recommended feedback voltage ripple is 20mV~100mV.
If a low ESR output capacitor is selected, then the
feedback voltage ripple may be too small to be sensed
by the g m amplifier and the error comparator. Also, the
output voltage ripple and the feedback voltage ripple are
not necessarily in phase with the inductor current ripple if
the ESR of the output capacitor is very low. In these
cases, ripple injection is required to ensure proper
operation. Please refer to “Ripple Injection” subsection in
Application Information for more details about the ripple
injection technique.
Figure 4. MIC2176 Current Limiting Circuit
November 2010
15
M9999-111710-A
相关PDF资料 |
PDF描述 |
|---|---|
| UPS1H102MHD | CAP ALUM 1000UF 50V 20% RADIAL |
| MIC2176-1YMM TR | IC REG CTRLR BUCK PWM 10-MSOP |
| H2ABT-10102-B8-ND | JUMPER-H1502TR/A3048B/H1500TR 2" |
| H2ABT-10102-A8-ND | JUMPER-H1502TR/A3048A/H1500TR 2" |
| IDC7328ER331M | INDUCTOR POWER 330UH 1.0A SMD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC2176-3 | 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 |
| MIC2176-3YMM | 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 |
| MIC2176-3YMM TR | 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 |
| MIC2177 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:2.5A Synchronous Buck Regulator |
| MIC2177_08 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:2.5A Synchronous Buck Regulator |
发布紧急采购，3分钟左右您将得到回复。