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參數(shù)資料
| 型號： | MAX1855 |
| 廠商： | Maxim Integrated Products, Inc. |
| 元件分類： | 數(shù)字信號處理 |
| 英文描述： | Fixed-Point Digital Signal Processor 352-FC/CSP 0 to 0 |
| 中文描述： | 高速、數(shù)字可調(diào)、同步降壓型控制器，集成電壓定位電路 |
| 文件頁數(shù)： | 15/33頁 |
| 文件大?。?/td> | 840K |
| 代理商： | MAX1855 |
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M
High-Speed, Adjustable, Synchronous Step-Down
Controllers with Integrated Voltage Positioning
______________________________________________________________________________________
15
tor is low, the low-side switch current is below the cur-
rent-limit threshold, and the minimum off-time one-shot
has timed out.
On-Time One-Shot (TON)
The heart of the PWM core is the one-shot that sets the
high-side switch on-time. This fast, low-jitter, adjustable
one-shot includes circuitry that varies the on-time in
response to the input and output voltages. The high-
side switch on-time is inversely proportional to V+, and
directly proportional to the output voltage as set by the
DAC code. This algorithm results in a nearly constant
switching frequency despite the lack of a fixed-frequen-
cy clock generator. The benefits of a constant switch-
ing frequency are twofold: first, the frequency can be
selected to avoid noise-sensitive regions, such as the
455kHz IF band; second, the inductor ripple-current
operating point remains relatively constant, resulting in
easy design methodology and predictable output volt-
age ripple.
On-Time = K
×
(V
OUT
+ 75mV) / V+
where K is set by the TON pin-strap connection, and
75mV is an approximation to accommodate for the
expected drop across the low-side MOSFET switch and
current-sense resistor (Table 3).
The on-time one-shot has good accuracy at the operat-
ing points specified in the
Electrical Characteristics
table. On-times at operating points far removed from
the conditions specified in the
Electrical Characteristics
table can vary over a wide range. For example, the
550kHz setting will typically run about 10% slower with
inputs much greater than the +5V due to the very short
on-times required.
While the on-time is set by TON, V+, and the output
voltage, other factors also contribute to the overall
V
CC
C
OUT
(5) 220
μ
F
PANASONIC
D2
L1
0.68
μ
H
1.6V OUTPUT
UP TO 18A
SHDN
VGATE
D1
C4
1
μ
F
C3
0.1
μ
F
Q1
Q2
C5
1
μ
F
R3
10
C
(5) 10
μ
F
BATTERY (V
BATT
)
7V TO 24V
REF
ILIM
CC
+5V INPUT
BIAS SUPPLY
POWER-GOOD
INDICATOR
DL
LX
V+
DH
BST
CS
PGND
VPS
FB
TON
V
DD
MAX1716
MAX1854
MAX1855
SKIP
D0
D1
D2
D3
D4
GND
R6
100k
TO V
CC
R4
100k
R5
200k
C2
47pF
C1
0.22
μ
F
ON OFF
R2
1k
FLOAT (300kHz)
MAX1716 DAC CODE SHOWN
R1
1k
R
SENSE
3m
Q1: (2) IRF7811
INTERNATIONAL RECTIFIER
Q2: (2) IRF7811
INTERNATIONAL RECTIFIER
D1: CMPSH-3
CENTRAL SEMICONDUCTOR
D2: CMSH2-60
CENTRAL SEMICONDUCTOR
Figure 1. Standard High-Power Application (Circuit #1)
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MAX1854EEG | High-Speed, Adjustable, Synchronous Step-Down Controllers with Integrated Voltage Positioning |
| MAX1855EEG | Replaced by TMS320C6202B : Fixed-Point Digital Signal Processor 352-FCBGA |
| MAX1854 | High-Speed, Adjustable, Synchronous Step-Down Controllers with Integrated Voltage Positioning |
| MAX1857EUA47 | 500mA, Low-Dropout, Ripple-Rejecting LDO in MAX |
| MAX1857 | Replaced by TMS320C6202B : Fixed-Point Digital Signal Processor 352-FCBGA |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1855EEG | 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| MAX1855EEG+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX1855EEG-T | 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| MAX1855EVKIT | 功能描述:DC/DC 開關(guān)控制器 Evaluation Kit for the MAX1716 MAX1854 MAX1855 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| MAX1856EUB | 功能描述:電信線路管理 IC RoHS:否 制造商:STMicroelectronics 產(chǎn)品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray |
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