参数资料
| 型号： | ISL6723AABZ |
| 厂商： | Intersil |
| 文件页数： | 14/24页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR PWM CM 16-SOIC |
| 标准包装： | 960 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1MHz |
| 占空比： | 100% |
| 电源电压： | 9 V ~ 18 V |
| 降压： | 是 |
| 升压： | 是 |
| 回扫： | 是 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 是 |
| 工作温度： | -40°C ~ 105°C |
| 封装/外壳： | 16-SOIC（0.154"，3.90mm 宽） |
| 包装： | 管件 |
ISL6722A, ISL6723A
Design Criteria
The following design requirements were selected:
Switching Frequency, f sw : 200kHz
V IN : 36V to 75V
V OUT(1) : 3.3V @ 2.5A
V OUT(2) : 1.8V @ 1.0A
Input Power:
P OUT /Efficiency = 14.3W (use 15W)
Max On Time: t ON(max) = Dmax/fsw = 2.25μs
Average Input Current: Iavg(in) = Pin/Vin(min) = 0.42A
Peak Primary Current:
2 ? Iavg ( in )
fsw ? t ON ( max )
V OUT(Bias) : 12V @ 50mA
P OUT : 10W
Ippk = ------------------------------------------- = 1.87
A
(EQ. 21)
Vin ( min ) ? t ON ( max )
Efficiency: 70%
Maximum Duty Cycle, Dmax: 0.45
Maximum Primary Inductance:
Lp ( max ) = ----------------------------------------------------------- = 43.3
Ippk
μ H
(EQ. 22)
Transformer Design
The design of a flyback transformer is a non-trivial affair. It is
an iterative process which requires a great deal of
experience to achieve the desired result. It is a process of
many compromises, and even experienced designers will
Choose desired primary inductance to be 40μH.
The core structure must be able to deliver a certain amount
of energy to the secondary on each switching cycle in order
to maintain the specified output power.
Δ w = Pout ? ---------------------------------
produce different designs when presented with identical
requirements. The iterative design process is not presented
? Vout + Vd ?
Fsw ? Vout
joules
(EQ. 23)
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.
where Δ w is the amount of energy required to be transferred
each cycle and Vd is the drop across the output rectifier.
The capacity of a gapped ferrite core structure to store
energy is dependent on the volume of the airgap and can be
2 ? μ o ? Δ w
Δ B
? Select suitable core material(s).
? Select maximum flux density desired for operation.
expressed as:
Vg = Aeff ? lg = -----------------------------
2
m
3
(EQ. 24)
? 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. For flyback transformers, the ability to store
energy is the critical factor in determining the core size.
The cross sectional area of the core and the length of the
air gap in the magnetic path determine the energy storage
capability.
? 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 required based on flux density and energy storage
calculations.
? Determine the number of primary turns.
? Determine the turns ratio.
? Select the wire gauge for each winding.
? Determine winding order and insulation requirements.
? Verify the design.
14
where Aeff is the effective cross sectional area of the core in
m 2 , lg is the length of the airgap in meters, μ o is the
permeability of free space (4 π ? 10 -7 ), and Δ B is the change
in flux density in Tesla.
A core structure having less airgap volume than calculated
will be incapable of providing the full output power over
some portion of its operating range. On the other hand, if the
length of the airgap becomes large, magnetic field fringing
around the gap occurs. This has the effect of increasing the
airgap volume. Some fringing is usually acceptable, but
excessive fringing can cause increased losses in the
windings around the gap resulting in excessive heating.
Once a suitable core and gap combination are found, the
iterative design cycle begins. A design is developed and
checked for ease of assembly and thermal performance. If
the core does not allow adequate space for the windings,
then a core with a larger window area is required. If the
transformer runs hot, it may be necessary to lower the flux
density (more primary turns, lower operating frequency),
select a less lossy core material, change the geometry of the
windings (winding order), use heavier gauge wire or multi-
filar windings, and/or change the type of wire used (Litz wire,
for example).
FN9237.1
July 11, 2007
相关PDF资料 |
PDF描述 |
|---|---|
| ISL6726AAZ-T7A | IC REG CTRLR ISO PWM CM 20-QSOP |
| ISL6729IU-T | IC REG CTRLR BST FLYBK ISO 8MSOP |
| ISL6740AIVZA | IC REG CTRLR PWM VM 16-TSSOP |
| ISL6741IV-T | IC REG CTRLR PWM CM 16-TSSOP |
| ISL6742AAZA-T | IC REG CTRLR PWM CM/VM 16-QSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6723AABZ-T | 功能描述:IC REG CTRLR PWM CM 16-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL6726AAZ | 功能描述:IC REG CTRLR ISO PWM CM 20-QSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:75 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.3 V ~ 13.5 V 降压:是 升压:是 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:0°C ~ 70°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:管件 产品目录页面:1051 (CN2011-ZH PDF) 其它名称:296-2543-5 |
| ISL6726AAZ-T | 功能描述:IC REG CTRLR ISO PWM CM 20-QSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL6726AAZ-T7A | 功能描述:IC REG CTRLR ISO PWM CM 20-QSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL6726EVAL1Z | 制造商:Intersil Corporation 功能描述:ISL6726 EVALUATION BOARD 1 - 20 LD QSOP - ROHS COMPLIAN - Bulk 制造商:Intersil Corporation 功能描述:BOARD EVAL FOR ISL6726 制造商:Intersil Corporation 功能描述:ISL6726 EVALUATION BOARD 1 - 20 Ld QSOP - ROHS COMPLIAN |
发布紧急采购，3分钟左右您将得到回复。