参数资料
| 型号： | MIC2166YMME TR |
| 厂商： | Micrel Inc |
| 文件页数： | 11/28页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR PWM HYBRID 10TSOP |
| 标准包装： | 2,500 |
| 系列： | Hyper Speed Control™ |
| PWM 型： | 混合物 |
| 输出数： | 1 |
| 频率 - 最大： | 750kHz |
| 占空比： | 82% |
| 电源电压： | 4.5 V ~ 28 V |
| 降压： | 无 |
| 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）裸露焊盘 |
| 包装： | 带卷 (TR) |
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Micrel, Inc.
Functional Description
The MIC2166 is an adaptive on-time buck controller built
for low cost and high performance. Featuring an internal
5V linear regulator and Power-Good (PGOOD) output, it
is designed for a wide input voltage range from 4.5V to
28V, high output power buck converters. An estimated
ON-time method is used in the MIC2166 to obtain a
constant switching frequency and to simplify the control
compensation. Over-current protection is implemented
without the use of an external sense resistor. It includes
an internal soft-start function which reduces the power
supply input surge current at start-up by controlling the
output voltage rise time.
Theory of Operation
The MIC2166 is an adaptive on-time buck controller.
Figure 1 illustrates the block diagram for the control loop.
The output voltage variation will be sensed by the
MIC2166 feedback pin FB via the voltage divider. The
FB voltage V FB is compared to a 0.8V reference voltage
V REF at the error comparator through a low gain
transconductance (g m ) amplifier at switching frequency.
This g m amplifier improves the MIC2166 converter output
voltage regulation. If the FB voltage V FB decreases and
the output of the g m amplifier is below 0.8V, The error
comparator will trigger the control logic and generate an
ON-time period, in which DH pin is logic high and DL pin
is logic low. The ON-time period length is predetermined
by the “Fixed T ON Estimator” circuitry:
MIC2166
where T S = 1/f SW . It is not recommended to use MIC2166
with a OFF-time close to T OFF(min) during steady state
operation. Also, as V OUT increases, the internal ripple
injection will increase and reduce the line regulation
performance. Therefore, the maximum output voltage of
the MIC2166 should be limited to 5.5V. Please refer to
“Setting Output Voltage” subsection in “Application
Information” for more details.
The estimated ON-time method results in a constant
switching frequency in the MIC2166. The actual ON-time
varies slightly with the different rising and falling times of
the external MOSFETs. Therefore, the type of the
external MOSFETs and the output load current will
modify the actual ON-time and the switching frequency.
Also, the minimum T ON results in a lower switching
frequency in high V IN and low V OUT applications, such as
24V to 1.0V. The minimum T ON measured on the
MIC2166 evaluation board is about 100ns. During the
load transient, the switching frequency is changed due to
the varying OFF-time.
To illustrate the control loop, the steady-state and load-
transient scenarios are analyzed. For easy analysis, the
gain of the g m amplifier is assumed to be 1. With this
assumption, the inverting input of the error comparator is
the same as V FB . Figure 2 shows the MIC2166 control
loop timing during steady-state operation. During steady-
state, the g m amplifier senses V FB ripple, which is
proportional to the output voltage (V OUT ) ripple and the
inductor current ripple, to trigger the ON-time period. The
ON-time is predetermined by the estimation. The ending
T ON(estimat ed) =
V OUT
V IN × f sw
(1)
of OFF-time is controlled by V FB . At the valley of V FB
ripple, which occurs when V FB falls below V REF , the OFF
period ends and the next ON-time period is triggered
through the control logic circuitry.
where V OUT is the output voltage, V IN is the power stage
input voltage, and f SW is the switching frequency
(600kHz for MIC2166).
After an ON-time period, the MIC2166 goes into the
OFF-time period, in which DH pin is logic low and DL pin
is logic high. The OFF-time period length depends on
V FB in most cases. When V FB decreases and the output
of the g m amplifier is below 0.8V, the ON-time period is
triggered and the OFF-time period ends. If the OFF-time
period determined by V FB is less than the minimum OFF
time T OFF(min) , which is about 300ns typical, then the
MIC2166 control logic will apply the T OFF(min) instead.
T OFF(min) is required to maintain enough energy in the
boost capacitor (C BST ) to drive the high-side MOSFET.
The maximum duty-cycle is obtained from the 300ns
T OFF(min) :
Figure 2. MIC2166 Control Loop Timing
D MAX =
T S ? T OFF(min)
T S
= 1 ?
300ns
T S
September 2010
11
M9999-092410-C
相关PDF资料 |
PDF描述 |
|---|---|
| MIC2168AYMM | IC REG CTRLR BUCK PWM VM 10-MSOP |
| MIC2168BMM TR | IC REG CTRLR BUCK PWM VM 10-MSOP |
| MIC2169AYMM | IC REG CTRLR DIVIDER PWM 10-MSOP |
| MIC2169BMM TR | IC REG CTRLR BUCK PWM VM 10-MSOP |
| MIC2169BYMME | IC REG CTRLR BUCK PWM VM 10-MSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC2168 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:1MHz PWM Synchronous Buck Control IC |
| MIC2168_05 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:1MHz PWM Synchronous Buck Control IC |
| MIC2168A | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:1MHz PWM Synchronous Buck Control IC |
| MIC2168ABMM | 功能描述:IC REG CTRLR BUCK PWM VM 10-MSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
| MIC2168ABMM TR | 功能描述:IC REG CTRLR BUCK PWM VM 10-MSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
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