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参数资料
| 型号： | IRDC3637 |
| 厂商： | International Rectifier |
| 文件页数： | 6/21页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL SYNC BUCK REGULATOR |
| 产品变化通告： | (EP) Parts Discontinuation 25/May/2012 |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 1.8V |
| 电流 - 输出： | 7A |
| 输入电压： | 4.5 ~ 5.5 V |
| 稳压器拓扑结构： | 降压 |
| 频率 - 开关： | 400kHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | IR3637 |
| 产品目录页面： | 1383 (CN2011-ZH PDF) |
| 相关产品： | IR3637ASTRPBFTR-ND - IC REG CTRLR BUCK PWM VM 8-SOIC IR3637ASPBF-ND - IC REG CTRLR BUCK PWM VM 8-SOIC IR3637STRPBFDKR-ND - IC REG CTRLR BUCK PWM VM 8-SOIC IR3637STRPBFCT-ND - IC REG CTRLR BUCK PWM VM 8-SOIC IR3637STRPBFTR-ND - IC REG CTRLR BUCK PWM VM 8-SOIC IR3637SPBF-ND - IC REG CTRLR BUCK PWM VM 8-SOIC |
IR3637SPBF
APPLICATION INFORMATION
Css ? 25 × t START ( μ F)
---(2)
Design Example:
The following example is a typical application for IR3637.
Appliaction circuit is shown in page 12.
V IN = Vcc = 5V
Vc=12V
V OUT = 1.8V
I OUT = 6A
? V OUT = 50mV
F S = 400kHz
Output Voltage Programming
Output voltage is programmed by reference voltage and
external voltage divider. The Fb pin is the inverting input
of the error amplifier, which is internally referenced to
0.8V. The divider is ratioed to provide 0.8V at the Fb pin
when the output is at its desired value. The output volt-
age is defined by using the following equation:
Where t START is the desired start-up time (ms)
For a start-up time of 4ms, the soft-start capacitor will
be 0.1 μ F. Choose a ceramic capacitor at 0.1 μ F.
Boost Supply for Single 5V appliaction
To drive the high side switch, it is necessary to supply a
gate voltage at least 4V grater than the bus voltage. This
is achieved by using a charge pump configuration as
shown in Figure 6. This method is simple and inexpen-
sive. The operation of the circuit is as follows: when the
lower MOSFET is turned on, the capacitor (C1) is pulled
down to ground and charges, up to V BUS value, through
the diode (D1). The bus voltage will be added to this
voltage when upper MOSFET turns on in next cycle,
and providing supply voltage (Vc) through diode (D2). Vc
is approximately:
( R R )
1+
V OUT = V REF ×
6
5
---(1)
Vc ? 2V BUS - (V D1 + V D2 )
Capacitors in the range of 0.1 μ F and 1 μ F are generally
When an external resistor divider is connected to the
output as shown in Figure 5.
adequate for most applications. The diode must be a
fast recovery device to minimize the amount of charge
IR3637
Fb
V OUT
R 6
R 5
fed back from the charge pump capacitor into V BUS . The
diodes need to be able to block the full power rail volt-
age, which is seen when the high side MOSFET is
switched on. For low voltage application, schottky di-
odes can be used to minimize forward drop across the
diodes at start up.
V BUS
D1
Figure 5 - Typical application of the IR3637 for pro-
gramming the output voltage.
C3
Vc
D2
V BUS
Equation (1) can be rewritten as:
C2
C1
Q1
(
R 6 = R 5 ×
)
V OUT
V REF
Choose R 5 = 1K ?
-1
IR3637
HDrv
Q2
L
This will result to R 6 = 1.25K ?
If the high value feedback resistors are used, the input
bias current of the Fb pin could cause a slight increase
in output voltage. The output voltage set point can be
more accurate by using precision resistor.
Soft-Start Programming
The soft-start timing can be programmed by selecting
the soft-start capacitance value. The start-up time of the
converter can be calculated by using:
Figure 6 - Charge pump circuit.
Input Capacitor Selection
The input filter capacitor should be based on how much
ripple the supply can tolerate on the DC input line. The
ripple current generated during the on time of upper
MOSFET should be provided by input capacitor. The RMS
value of this ripple is expressed by:
6
www.irf.com
Rev.1.1
06/16/05
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相关代理商/技术参数 |
参数描述 |
|---|---|
| IRDC3637EVAL | 制造商:IRF 制造商全称:International Rectifier 功能描述:IR3637 EVALUATION BOARD USER GUIDE |
| IRDC3640 | 功能描述:电源管理IC开发工具 IR3640 12V PWM 1.5MHz Controller 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 |
| IRDC3651 | 功能描述:电源管理IC开发工具 IR3651 EVAL BRD 400kHz 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 |
| IRDC3710-DF | 功能描述:电源管理IC开发工具 1 PHASE SYNC-BUCK PWM CTRLLER 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 |
| IRDC3710-QFN | 功能描述:电源管理IC开发工具 1 PHASE SYNC-BUCK PWM CTRLLER 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 |
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