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参数资料
| 型号： | MIC2168YMM TR |
| 厂商： | Micrel Inc |
| 文件页数： | 6/14页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 10-MSOP |
| 标准包装： | 2,500 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1.1MHz |
| 占空比： | 90% |
| 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 ~ 125°C |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 包装： | 带卷 (TR) |
| 其它名称： | MIC2168YMMTR MIC2168YMMTR-ND |
MIC2168
Functional Diagram
C IN
RCS
Micrel, Inc.
V IN
CS
V DD
5V
5V LDO
V DD
5V
Current Limit
Comparator
High-Side
Driver
HSD
Q1
D1
Bandgap
Reference
0.8V
BG Valid
Current Limit
Reference
BOOST
4W
SW RSW
C BST
L1
V OUT
0.8V
5V
Soft-Start &
Digital Delay
Counter
Enable
Error
Loop
Error
Amp
Clamp &
Startup
Current
Ramp
Clock
PWM
Comparator
V REF +3%
V REF 3%
Hys
Comparator
Driver
Logic
5V
Low-Side
Driver
LSD
FB
R3
Q2
C OUT
R2
MIC2168
COMP
GND
C2
C1
R1
MIC2168 Block Diagram
Functional Description
The MIC2168 is a voltage mode, synchronous step-down
switching regulator controller designed for high output power
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 volt-
age rise time, a PWM generator, a reference voltage, two
MOSFET drivers, and short-circuit current limiting circuitry
to form a complete 1MHz switching regulator.
Theory of Operation
The MIC2168 is a voltage mode step-down regulator. The
?gure above illustrates the block diagram for the voltage
control loop. The output voltage variation due to load or line
changes will be sensed by the inverting input of the transcon-
ductance error ampli?er via the feedback resistors R3, and
R2 and compared to a reference voltage at the non-invert-
ing input. This will cause a small change in the DC voltage
level at the output of the error ampli?er which is the input to
the PWM comparator. The other input to the comparator is
a 0 to 1V triangular waveform. The comparator generates
a rectangular waveform whose width t ON is equal to the
time from the start of the clock cycle t 0 until t 1 , the time the
triangle crosses the output waveform of the error ampli?er.
To illustrate the control loop, let us assume the output volt-
age drops due to sudden load turn-on, this would cause the
inverting input of the error ampli?er which is divided down
version of V OUT to be slightly less than the reference voltage
causing the output voltage of the error ampli?er to go high.
This will cause the PWM comparator to increase t ON time of
the top side MOSFET, causing the output voltage to go up
and bringing V OUT back in regulation.
Soft-Start
The COMP/EN pin on the MIC2168 is used for the following
three functions:
1. Disables the part by grounding this pin
2. External compensation to stabilize the voltage
control loop
3. Soft-start
For better understanding of the soft-start feature, let’s as-
sume V IN = 12V, and the MIC2168 is allowed to power-up
by un-grounding the COMP/EN pin. The COMP pin has an
internal 8.5 μ A current source that charges the external com-
pensation capacitor. As soon as this voltage rises to 180mV
(t = Cap_COMP × 0.18V/8.5 μ A), the MIC2168 allows the
internal V DD linear regulator to power up and as soon as it
crosses the undervoltage lockout of 2.6V, the chip’s internal
oscillator starts switching. At this point in time, the COMP
pin current source increases to 40 μ A and an internal 11-bit
counter starts counting which takes approximately 2ms to
complete. During counting, the COMP voltage is clamped
at 0.65V. After this counting cycle the COMP current source
M9999-040805
6
April 2005
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC2169 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:500kHz PWM Synchronous Buck Control IC |
| MIC2169_09 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:500kHz PWM Synchronous Buck Control IC |
| MIC2169A | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:500kHz PWM Synchronous Buck Control IC |
| MIC2169A_09 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:500kHz PWM Synchronous Buck Control IC |
| MIC2169ABMM | 功能描述:IC REG CTRLR DIVIDER PWM 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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