參數(shù)資料
型號(hào)： MAX1856
廠商： Maxim Integrated Products, Inc.
元件分類： 數(shù)字信號(hào)處理
英文描述： Replaced by TMS320C6202B : Fixed-Point Digital Signal Processor 352-FCBGA
中文描述： 寬輸入范圍、可同步的、PWM SLIC電源
文件頁(yè)數(shù)： 12/18頁(yè)
文件大小： 594K
代理商： MAX1856
M
Wide Input Range, Synchronizable,
PWM SLIC Power Supply
12
______________________________________________________________________________________
gives 1.11A for 80% efficiency. With a duty cycle of
52.5%, the average switch current (I
SW(AVG)
) is 2.114A.
Choosing a primary inductance ripple current
I
L
to be
40% of the average switch current, the primary induc-
tance is given by:
Selecting f
OSC
= 250kHz and
I
L
= 0.4 x I
SW(AVG)
=
0.846A, the primary inductance value is 27μH, and the
peak primary current for this example is therefore 2.5A.
Core Selection
The transformer in a flyback converter is a coupled
inductor with multiple windings on the same magnetic
core. Flyback topologies operate by storing energy in
the transformer magnetics during the on-time and
transferring this energy to the output during the off-
time.
Core selection depends on the core
’
s power-handling
capability. The required output power is first consid-
ered. For example, the standard application circuit
requires 9.6W. Assuming a typical 80% efficiency, the
transformer must support 12W of power. The core
material
’
s properties, the core
’
s shape, and the size of
the air gap determine the core
’
s power rating. Since the
equations relating these properties to the power capa-
bility are involved, manufacturers simply provide charts
giving
“
Power vs. Frequency
”
for different core sizes.
For the standard application circuit (f
OSC
= 250kHz),
the EFD15 core from Coiltronics meets the criteria.
Once the core is chosen, the number of turns in the pri-
mary is given by:
where A
L
is the inductance factor. Ensure that the num-
ber of ampere-turns (N
P
I
SAT
) is below the saturation
limit. A significant portion of the total energy is stored in
the air gap. Therefore, the larger the air gap, the lower
the A
L
value and the larger the number of ampere-turns
at which saturation starts. Some manufacturers define
saturation as the current at which the inductance
decreases by 30%.
Current-Sense Resistor Selection
Once the peak inductor current is determined, the cur-
rent-sense resistor (R
CS
) is determined by:
Kelvin-sensing should be used to connect CS and
PGND to R
CS
. Connect PGND and GND together at the
ground side of R
CS
.
Due to inductive ringing after the MOSFET turns on, a
lowpass filter may be required between R
CS
and CS to
prevent the noise from tripping the current-sense com-
parator. Connect a 100
resistor between CS and the
R
V
I
mV I
85
CS
CS MIN
(
LPEAK
LPEAK
=
=
)
/
N
L
A
P
P
L
=
L
V D
I
P
=
INPUT VOLTS (V)
5
OUTPUT VOLTS (V)
-48
OUTPUT CURRENT (mA)
100
TRANSFORMER (VENDOR)
VP3-0055 (Coiltronics)
12
-48
100
CTX01-14853 (Coiltronics), or
ICA-0635 (ICE Components)
12
-24 and -72
400 or 100
CTX01-14853 (Coiltronics), or
ICA-0635 (ICE Components)
12
-95 and -30
320 and 150
CTX03-15220 (Coiltronics)
Table 1. Transformer Selection for Standard Applications
VENDOR
USA PHONE
847-639-6400
888-414-2645
800-729-2099
858-674-8100
847-390-4461
USA FAX
847-639-1469
561-241-9339
703-257-7547
858-674-8262
847-390-4405
INTERNET
www.coilcraft.com
www.coiltronics.com
www.icecomponents.com
www.pulseeng.com
www.tdk.com
Coilcraft
Coiltronics
ICE Components
Pulse Engineering
TDK
Table 2. Transformer Suppliers
相關(guān)PDF資料
PDF描述
MAX1856EUB Replaced by TMS320C6202B : Fixed-Point Digital Signal Processor 352-FCBGA 0 to 0
MAX1864 Fixed-Point Digital Signal Processor 352-FCBGA
MAX1864-MAX1865 Fixed-Point Digital Signal Processor 384-FC/CSP
MAX1865 Fixed-Point Digital Signal Processor 352-FCBGA
MAX1864UEEE xDSL/Cable Modem Triple/Quintuple Output Power Supplies
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
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(fēng)格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
MAX1856EUB+ 功能描述:電信線路管理 IC Synchronizable PWM SLIC Power Supply 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(fēng)格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
MAX1856EUB+T 功能描述:電信線路管理 IC Synchronizable PWM SLIC Power Supply 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(fēng)格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
MAX1856EUB-T 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(fēng)格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
MAX1856EVKIT 功能描述:電源管理IC開(kāi)發(fā)工具 Evaluation Kit for the MAX1856 RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V
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