参数资料
型号: IRDC3637
厂商: International Rectifier
文件页数: 8/21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:
已用 IC / 零件: IR3637
产品目录页面: 1383 (CN2011-ZH PDF)
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IR3637SPBF
For this design, IRF8910 is a good choice. The device
provides two N-MOSFETs in a compact SOIC 8-Pin pack-
These values are taken under a certain condition test.
For more detail please refer to the IRF8910 data sheet.
age.
By using equation (6), we can calculate the switching
The IRF8910 has the following data:
V DSS = 20V
I D = 10A
R DS(onh) =18.3 ? @ V GS =4.5V (Lower FET)
R DS(on) =13.4 ? @ V GS =10V (Upper FET)
The total conduction losses will be:
P CON(TOTAL) =P CON (Upper Switch)+P CON (Lower Switch)
? = 1.4 according to the IRF8910 data sheet for
150 C junction temperature
losses.
P SW = 95mW
Feedback Compensation
The IR3637 is a voltage mode controller; the control loop
is a single voltage feedback path including error ampli-
fier and error comparator. To achieve fast transient re-
sponse and accurate output regulation, a compensation
circuit is necessary. The goal of the compensation net-
work is to provide a closed loop transfer function with the
highest 0dB crossing frequency and adequate phase
margin (greater than 45 ).
P CON(TOTAL) =0.83W
The output LC filter introduces a double pole, –40dB/
The switching loss is more difficult to calculate, even
though the switching transition is well understood. The
reason is the effect of the parasitic components and
decade gain slope above its corner resonant frequency,
and a total phase lag of 180 (see Figure 8). The Reso-
nant frequency of the LC filter expressed as follows:
switching times during the switching procedures such
as turn-on / turnoff delays and rise and fall times. The
control MOSFET contributes to the majority of the switch-
F LC =
2 π×
1
L O × C O
---(7)
ing losses in synchronous Buck converter. The synchro-
nous MOSFET turns on under zero voltage conditions,
therefore, the turn on losses for synchronous MOSFET
can be neglected. With a linear approximation, the total
switching loss can be expressed as:
Figure 8 shows gain and phase of the LC filter. Since we
already have 180 phase shift just from the output filter,
the system risks being unstable.
t r + t f × I LOAD
×
V DS(OFF)
P SW = ---(6)
2 T
Where:
V DS(OFF) = Drain to Source Voltage at off time
Gain
0dB
-40dB/decade
Phase
0
t r = Rise Time
t f = Fall Time
T = Switching Period
I LOAD = Load Current
F LC Frequency
-180
F LC
Frequency
The switching time waveform is shown in figure 7.
V DS
90%
10%
V GS
Figure 8 - Gain and phase of LC filter.
The IIR3637’s error amplifier is a differential-input transcon-
ductance amplifier. The output is available for DC gain
control or AC phase compensation.
The E/A can be compensated with or without the use of
local feedback. When operated without local feedback
the transconductance properties of the E/A become evi-
dent and can be used to cancel one of the output filter
t d (ON)
t r
t d (OFF)
t f
poles. This will be accomplished with a series RC circuit
from Comp pin to ground as shown in Figure 9.
Figure 7 - Switching time waveforms.
From IRF8910 data sheet:
t r = 10ns
t f = 4.1ns
8
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