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器件描述：High-Efficiency Synchronous Buck Controller Final Information
器件厂商：MICREL [Micrel Semiconductor]
厂商主页：http://www.micrel.com/
文件大小：223.27KB
文件页数：28
PDF阅读：MIC2182-5.0BSM.pdf (点击阅读器件资料)
摘要：
June 2000 1 MIC2182
MIC2182 Micrel
MIC2182
High-Efficiency Synchronous Buck Controller
Final Information
General Description
Micrel’s MIC2182 is a synchronous buck (step-down) switch-
ing regulator controller. An all N-channel synchronous archi-
tecture and powerful output drivers allow up to a 20A output
current capabilty. The PWM and skip-mode control scheme
allows efficiency to exceed 95% over a wide range of load
current, making it ideal for battery powered applications, as
well as high current distributed power supplies.
The MIC2182 operates from a 4.5V to 32V input and can
operate with a maximum duty cycle of 86% for use in low-
dropout conditions. It also features a shutdown mode that
reduces quiescent current to 0.1?A.
The MIC2182 achieves high efficiency over a wide output
current range by automatically switching between PWM and
skip mode. Skip-mode operation enables the converter to
maintain high efficiency at light loads by turning off circuitry
pertaining to PWM operation, reducing the no-load supply
current from 1.6mA to 600?A. The operating mode is inter-
nally selected according to the output load conditions. Skip
mode can be defeated by pulling the PWM pin low which
reduces noise and RF interference.
The MIC2182 is available in a 16-pin SOP (small-outline
package) and SSOP (shrink small-outline package) with an
operating range from –40°C to +85°C.
Typical Application
VDD
BST
C6
0.1?F
R1
2k
R7
100k
V
IN
4.5V to 30V*
V
OUT
3.3V/4A
GND
C2
2.2nF
C4
1nF
C3
0.1?F
C5
0.1?F
C1
0.1?F
C9
4.7?F
16V
C11
22uf
35V
x2
D2
SD103BWS
Q2*
Si4884
D1
B140
C7
220uf
10V ×2
L1
10?H
R2
0.02?
Q1*
Si4884
HSD
VSW
LSD
PGND
CSH
VOUT
VREF
SGND
GND
MIC2182-3.3BSM
VIN
EN/UVLO
SS
PWM
COMP
SYNC
C13, 1nF
10
6
2
1
3
5
4
7
9
8
12
13
15
16
14
11
* 30V maximum input voltage limit is due
to standard 30V MOSFET selection.
See “Application Information” section for
5V to 3.3V/10A and other circuits.
4.5V–30V* to 3.3V/4A Converter
Micrel, Inc. ? 1849 Fortune Drive ? San Jose, CA 95131 ? USA ? tel + 1 (408) 944-0800 ? fax + 1 (408) 944-0970 ? http://www.micrel.com
Features
? 4.5V to 32V Input voltage range
? 1.25V to 6V Output voltage range
? 95% efficiency
? 300kHz oscillator frequency
? Current sense blanking
? 5? impedance MOSFET Drivers
? Drives N-channel MOSFETs
? 600?A typical quiescent current (skip-mode)
? Logic controlled micropower shutdown (I
Q
< 0.1?A)
? Current-mode control
? Cycle-by-cycle current limiting
? Built-in undervoltage protection
? Adjustable undervoltage lockout
? Easily synchronizable
? Precision 1.245V reference output
? 0.6% total regulation
? 16-pin SOP and SSOP packages
? Frequency foldback overcurrent protection
? Sustained short-circuit protection at any input voltage
? 20A output current capability
Applications
? DC power distribution systems
? Notebook and subnotebook computers
? PDAs and mobile communicators
? Wireless modems
? Battery-operated equipment
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