收藏本站
IRU3065(PbF)
APPLICATION EXAMPLE
I OCP =
R S
V IN + V D - V OUT(NOM)
2
I OCP =
× × 1.5A = 357mA
V IN × (V D - V OUT(NOM) )
(V IN +V D -
L
= 1.45 μ H
(5 - (-5) + 0.5) × 1.2MHz
1.5A
V OUT(NOM) = - R3 × V REF
Design Example
The following design example is for the evaluation board
application for IRU3065. The schematic is shown in fig-
ure 1:
Where:
V IN = 5V
V OUT(NOM) = -5V
I OUT = 200mA
f S(MAX) = Maximum Frequency
f S(MAX) = 1.2MHz
V D = Diode Forward Voltage
V D = 0.5V
Vcc = 5V
VI SEN(TH) =145mV ? 150mV
Voltage Sensing Resistor
The output voltage is determined by the two voltage sens-
ing resistors R2 and R3:
R2
If R3 is chosen as 10K, Then R2 is given by:
The modified current I OCP is:
1 V IN 0.15
× ×
1 5
2 5 + 0.5 - (-5)
Output Inductor L
The inductance is chosen by equation (2):
L
V OUT(NOM) ) × f S(MAX) × I PEAK
5 -(-5 - 0.5)
×
Select L = 1.2 μ H
The maximum inductor current is: I PEAK = 1.5A
The maximum average inductor current equals
I AVG =(VI SENTH_MAX +VI SENTH_MIN )/Rs/2
I AVG =(145mV+50mV)/0.1ohm/2=1A
MOSFET Selection
× R3 = -
R2 = -
V REF
V OUT(NOM)
5V
-5V
× 10K = 10K ?
A P-channel MOSFET is required. The peak current in
this case is equal to I PEAK =1.5A. The MOSFET
IRLML5203, from international Rectifier with I D =3A and
Current Sensing Resistor R S
In order to select R S , the desired critical current I OCP
has to be determined. Considering the switching losses,
for conservative, the critical current should select to be
slightly greater than the nominal output current.
Select:
I OCP = 200mA × 1.5 = 300mA
Where 1.5 is the coefficient to take the efficiency into
account.
According to equation (1), the current I OCP is given by:
BVDSS=30V, is a good choice.
Input Capacitor
An input capacitor will help to minimize the induced
ripple on the +5V supply. A 1 μ F to 10 μ F X7R ceramic
capacitor is recommended.
Output Capacitor
An output capacitor is required to store energy from
transfer to the output inductor. Its capacitance and ESR
have a great impact on output voltage ripple. A 10 μ F to
22 μ F X7R Tantolum or ceramic capacitor is recom-
R S
I OCP =
1
2
0.15
× ×
V IN
V IN - V OUT(NOM) + V D
= 300mA
mended.
Output Diode
The current sensing resistance is calculated as:
The average diode current equals output current. In
R S =
I OCP
2
R S =
0.3
2
y 0.12 ?
1 0.15
× ×
1 0.15
× ×
Select R S = 0.1 ?
V IN
V IN - V OUT(NOM) + V D
5
5 - (-5) + 0.5
this case, select the diode average current larger than
300mA. The lowest block voltage is V IN +(-V OUT ). In this
case, It is 10V. In order to reduce the switching losses,
the Schottky diode is recommended. The diode 10BQ015
from International Rectifier with I D =1A and V BR =15V is
a good choice.
Other Components
I PEAK = = 1.5A
From equation (3), the modified inductor peak current
is:
VI SEN(TH)
R S
In order to speed up the turn off of P-channel MOSFET,
a fast diode 1N4148 or a 100ohm resistor and 100pF
capacitor is connected to the pin V DD and V GATE as shown
www.irf.com
5
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
R1D-0509/H-R CONV DC/DC 1W 05VIN +/-09VOUT
AS4PG-M3/87A DIODE STD 4A 400V SMPC
RS3-4815D/H2 CONV DC/DC 3W 36-72VIN +/-15VOUT
MAX6162BESA+ IC VREF SERIES PREC 2.048V 8SOIC
GBM30DCTH-S288 CONN EDGECARD 60POS .156 EXTEND
ECM08DRSH-S288 CONN EDGECARD 16POS .156 EXTEND
GEM12DTKI CONN EDGECARD 24POS DIP .156 SLD
ECM08DRSD-S288 CONN EDGECARD 16POS .156 EXTEND
相关代理商/技术参数
IRDC3073 功能描述:PWM CONTROLLER DESIGN KIT RoHS:否 类别:编程器，开发系统 >> 过时/停产零件编号 系列:- 标准包装:1 系列:- 类型:MCU 适用于相关产品:Freescale MC68HC908LJ/LK（80-QFP ZIF 插口） 所含物品:面板、缆线、软件、数据表和用户手册 其它名称:520-1035
IRDC3137 功能描述:KIT REFERENCE DESIGN W/IRU3137 RoHS:否 类别:编程器，开发系统 >> 过时/停产零件编号 系列:- 标准包装:1 系列:- 类型:MCU 适用于相关产品:Freescale MC68HC908LJ/LK（80-QFP ZIF 插口） 所含物品:面板、缆线、软件、数据表和用户手册 其它名称:520-1035
IRDC3138 制造商:Vishay Intertechnologies 功能描述:IRU3138, SYNCHRONOUS BUCK REGULATOR, EVAL BOARD, Silicon Manufacturer:Vishay, Si
IRDC3138EVAL 制造商:IRF 制造商全称:International Rectifier 功能描述:EVALUATION BOARD USER GUIDE
IRDC3146 功能描述:KIT REFERENCE DESIGN W/IRU3146 RoHS:否 类别:编程器，开发系统 >> 过时/停产零件编号 系列:- 标准包装:1 系列:- 类型:MCU 适用于相关产品:Freescale MC68HC908LJ/LK（80-QFP ZIF 插口） 所含物品:面板、缆线、软件、数据表和用户手册 其它名称:520-1035
IRDC3146EVAL 制造商:IRF 制造商全称:International Rectifier 功能描述:IRU3146 EVALUATION BOARD USER GUIDE
IRDC3473 功能描述:电源管理IC开发工具 9999V 999A POL IC RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V
IRDC3475 功能描述:电源管理IC开发工具 9999V 999A POL IC RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V