參數(shù)資料
型號： ISL6740
廠商： Intersil Corporation
英文描述： Flexible Double Ended Voltage and Current Mode PWM Controllers
中文描述： 靈活的雙端電壓和電流模式PWM控制器
文件頁數(shù)： 15/29頁
文件大?。?/td> 639K
代理商： ISL6740
15
Circuit Element Descriptions
The converter design may be broken down into the following
functional blocks:
Input Filtering: L1, C1, R1
Half-Bridge Capacitors: C2, C3
Isolation Transformer: T1
Primary Snubber: C13, R10
Start Bias Regulator: CR3, R2, R7, C6, Q5, D1
Supply Bypass Components: R3, C15, C4, C5
Main MOSFET Power Switch: QH, QL
Current Sense Network: T2, CR1, CR2, R5, R6, R11, C10, C14
Control Circuit: U3, RT1, R14, R19, R13, R15, R17, R18,
C16, C18, C17
Output Rectification and Filtering: QR1, QR2, QR3, QR4, L2,
C9, C8
Secondary Snubber: R8, R9, C11, C12
FET Driver: U1
ZVS Resonant Delay (Optional): L3, C7
Design Criteria
The following design requirements were selected:
Switching Frequency, Fsw: 235kHz
V
IN
: 48 ±10%V
V
OUT
: 12V (nominal) @ I
OUT
= 8A
P
OUT
: 100W
Efficiency: 95%
Ripple: 1%
Transformer Design
The design of a transformer for a half-bridge application is a
straight forward affair, although iterative. It is a process of
many compromises, and even experienced designers will
produce different designs when presented with identical
requirements. The iterative design process is not presented
here for clarity.
The abbreviated design process follows:
Select a core geometry suitable for the application.
Constraints of height, footprint, mounting preference,
and operating environment will affect the choice.
Determine the turns ratio.
Select suitable core material(s).
Select maximum flux density desired for operation.
Select core size. Core size will be dictated by the
capability of the core structure to store the required
energy, the number of turns that have to be wound, and
the wire gauge needed. Often the window area (the
space used for the windings) and power loss determine
the final core size.
Determine maximum desired flux density. Depending
on the frequency of operation, the core material
selected, and the operating environment, the allowed
flux density must be determined. The decision of what
flux density to allow is often difficult to determine
initially. Usually the highest flux density that produces
an acceptable design is used, but often the winding
geometry dictates a larger core than is indicated based
on flux density alone.
Determine the number of primary turns.
Select the wire gauge for each winding.
Determine winding order and insulation requirements.
Verify the design.
For this application we have selected a planar structure to
achieve a low profile design. A PQ style core was selected
because of its round center leg cross section, but there are
many suitable core styles available.
Since the converter is operating open loop at nearly 100%
duty cycle, the turns ratio, N, is simply the ratio of the input
voltage to the output voltage divided by 2.
The factor of 2 divisor is due to the half-bridge topology. Only
half of the input voltage is applied to the primary of the
transformer.
A PC44HPQ20/6 “E-Core” plus a PC44PQ20/3 “I-Core” from
TDK were selected for the transformer core. The ferrite
material is PC44.
The core parameter of concern for flux density is the
effective core cross sectional area, Ae. For the PQ core
pieces selected:
Ae = 0.62cm
2
or 6.2e -5m
2
Using Faraday’s Law, V = N d
Φ
/dt, the number of primary
turns can be determined once the maximum flux density is
set. An acceptable Bmax is ultimately determined by the
FIGURE 7. TRANSFORMER SCHEMATIC
n
P
n
SR
n
S
n
S
n
SR
N
V
OUT
2
------------------------
2
---------------
2
=
=
=
(EQ. 14)
ISL6740, ISL6741
相關(guān)PDF資料
PDF描述
ISL6740IB Flexible Double Ended Voltage and Current Mode PWM Controllers
ISL6740IV Octal Buffers/Drivers With 3-State Outputs 20-SSOP -40 to 85
ISL6741 Flexible Double Ended Voltage and Current Mode PWM Controllers(靈活的雙端電壓和電流模式PWM控制器)
ISL6845IB Improved Industry Standard Single Ended Current Mode PWM Controller
ISL6845 Improved Industry Standard Single Ended Current Mode PWM Controller
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ISL6740AIVZA 功能描述:IC REG CTRLR PWM VM 16-TSSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:275kHz 占空比:50% 電源電壓:18 V ~ 110 V 降壓:無 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:是 工作溫度:-40°C ~ 85°C 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR)
ISL6740AIVZA-T 功能描述:IC REG CTRLR PWM VM 16-TSSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:275kHz 占空比:50% 電源電壓:18 V ~ 110 V 降壓:無 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:是 工作溫度:-40°C ~ 85°C 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR)
ISL6740EVAL1 功能描述:EVALUATION BOARD 1 ISL6740 RoHS:否 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - DC/DC 與 AC/DC（離線）SMPS 系列:- 產(chǎn)品培訓模塊:Obsolescence Mitigation Program 標準包裝:1 系列:True Shutdown™ 主要目的:DC/DC，步升 輸出及類型:1，非隔離 功率 - 輸出:- 輸出電壓:- 電流 - 輸出:1A 輸入電壓:2.5 V ~ 5.5 V 穩(wěn)壓器拓撲結(jié)構(gòu):升壓 頻率 - 開關(guān):3MHz 板類型:完全填充 已供物品:板 已用 IC / 零件:MAX8969
ISL6740EVAL2 功能描述:EVALUATION BOARD 2 ISL6740 RoHS:否 類別:編程器，開發(fā)系統(tǒng) >> 過時/停產(chǎn)零件編號 系列:- 標準包裝:1 系列:- 傳感器類型:CMOS 成像，彩色（RGB） 傳感范圍:WVGA 接口:I²C 靈敏度:60 fps 電源電壓:5.7 V ~ 6.3 V 嵌入式:否 已供物品:成像器板 已用 IC / 零件:KAC-00401 相關(guān)產(chǎn)品:4H2099-ND - SENSOR IMAGE WVGA COLOR 48-PQFP4H2094-ND - SENSOR IMAGE WVGA MONO 48-PQFP
ISL6740EVAL2Z 功能描述:EVALUATION BOARD 2 ISL6740 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - DC/DC 與 AC/DC（離線）SMPS 系列:- 產(chǎn)品培訓模塊:Obsolescence Mitigation Program 標準包裝:1 系列:True Shutdown™ 主要目的:DC/DC，步升 輸出及類型:1，非隔離 功率 - 輸出:- 輸出電壓:- 電流 - 輸出:1A 輸入電壓:2.5 V ~ 5.5 V 穩(wěn)壓器拓撲結(jié)構(gòu):升壓 頻率 - 開關(guān):3MHz 板類型:完全填充 已供物品:板 已用 IC / 零件:MAX8969
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