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| 型号： | A4401KL-T |
| 厂商： | Allegro Microsystems Inc |
| 文件页数： | 10/17页 |
| 文件大小： | 0K |
| 描述： | IC QUASI FLYBACK CONVERTER 8SOIC |
| 标准包装： | 98 |
| 显示器类型： | 真空荧光 (VF) |
| 电流 - 电源： | 2.3mA |
| 电源电压： | 7 V ~ 40 V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 8-SOICN |
| 包装： | 管件 |
A4401
Automotive Quasi-Resonant Flyback Control IC
I PEAK (max) =
V BAT (min) × D (max)
f SW (min) × L PRI
V BAT (min) × D (max)
f SW (min) × B OP × A e
? Magnetics sizing can be determined using techniques
such as area product or geometric product, or by fol-
lowing manufacturers guidelines, usually in the form
of nomograms.
To simplify the design process, the resonant switch-
ing transition is ignored and the calculations are based
on the switcher operating at the boundary condition
of continuous/discontinuous conduction. This is a
reasonable assumption as the resonant period forms a
small percentage of the overall period at minimum line
voltage and maximum load (where the magnetics are
designed because of worst case conditions).
The objective of the design is to achieve 0 V switch-
ing when V BAT = 13.5 V (note that this voltage can be
adjusted for any value). At V BAT voltages of less than
13.5 V, 0 V switching is still achieved. In addition, the
LX voltage is prevented from swinging negative as
the MOSFET, Q1, is commanded on as soon as 0 V is
Then, maximum peak current can be found:
. (22)
The worst case operating flux density, B OP , can be
found from the ferrite core manufacturers datasheet,
by taking the saturation flux density, B SAT , at elevated
temperatures and subtracting a margin, approximately
15% , to allow for operation in current limit mode or
during startup.
After an appropriate magnetic core set has been
selected, the number of turns required on the primary
winding can be found:
N P = . (23)
where A e is the magnetics cross-sectional area in m 2 .
The number of secondary turns can be derived through
the turns ratio found previously:
reached.
To ensure that the reflected output voltage forces the
N S1 = n × N P
.
(24)
LX node to 0 V, the following condition must be met:
If there is more than one output, the additional second-
n =
V OUT
13.5
,
(19)
ary windings are simply scaled from the main second-
ary as shown in the following formula:
where n is the step-up turns ratio from primary to con-
trolled output.
N S2 = N S1 ×
V OUT2
V OUT1
,
(25)
V OUT
(20)
L PRI = × ( V BAT (min) × D (max)) 2 . (21)
Worst case conditions in terms of core saturation
occur when V BAT is at a minimum and duty cycle, D, a
maximum:
D (max) = .
( V BAT (min) × n ) + V OUT
The primary magnetizing inductance can be deter-
mined from the following formula, which is derived
by equating the input energy to the output energy
times the efficiency:
2 × f SW (min) × P OUT
where:
N S2 is the quantity of turns in the additional wind-
ings,
V OUT1 is the output voltage from main winding, and
V OUT2 is the output voltage from any additional
windings.
The total air gap, l g , can be found. First, an approxi-
mate air gap, l g (approx), is found before flux fringing
is taken into account. Given:
μ O = 4 × 10 -6 , (26)
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
10
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
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相关代理商/技术参数 |
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| A4401KLTR-T | 功能描述:IC QUASI FLYBACK CONVERTER 8SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 显示器驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 显示器类型:真空荧光 (VF) 配置:5 x 7（矩阵） 接口:串行 数字或字符:- 电流 - 电源:3.5mA 电源电压:2.7 V ~ 3.6 V 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:16-SSOP（0.154"，3.90mm 宽） 供应商设备封装:16-QSOP 包装:带卷 (TR) |
| A4402 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Constant On-Time Buck Converter with Integrated Linear Regulator |
| A4402_1 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Constant On-Time Buck Converter with Integrated Linear Regulator |
| A4402_12 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:The A4402 is a dual-output regulator, combining in a single package a constant on-time buck regulator and a linear regulator (LDO)a??each with adjustable output voltages. |
| A4402ELPTR-T | 功能描述:IC REG DL BUCK/LINEAR 16-TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 + 切换式 系列:- 标准包装:2,500 系列:- 拓扑:降压（降压）同步（3），线性（LDO）（2） 功能:任何功能 输出数:5 频率 - 开关:300kHz 电压/电流 - 输出 1:控制器 电压/电流 - 输出 2:控制器 电压/电流 - 输出 3:控制器 带 LED 驱动器:无 带监控器:无 带序列发生器:是 电源电压:5.6 V ~ 24 V 工作温度:-40°C ~ 85°C 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:* |
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