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参数资料
| 型号： | IRU3039CHTR |
| 厂商： | International Rectifier |
| 文件页数： | 10/22页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 20-MLPQ |
| 标准包装： | 1 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 400kHz |
| 占空比： | 88% |
| 电源电压： | 4.75 V ~ 20 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 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： | 20-MLPQ |
| 包装： | 剪切带 (CT) |
| 其它名称： | *IRU3039CHTR IRU3039CHTRCT |
IRU3039(PbF)
Choose IRF7466 for control MOSFET and IRF7458 for
synchronous MOSFET. These devices provide low on-
resistance in a compact SOIC 8-Pin package.
The MOSFETs have the following data:
These values are taken under a certain condition test.
For more details please refer to the IRF7466 and IRF7458
data sheets.
By using equation (12), we can calculate the total switch-
IRF7466
V DSS = 30V
I D = 11A
R DS(ON) = 12.5m ?
IRF7458
V DSS = 30V
I D = 14A
R DS(ON) = 8m ?
ing losses.
P SW(TOTAL) = 92mW
Programming the Over-Current Limit
The over-current threshold can be set by connecting a
t r + t f × I LOAD
P SW =
---(12)
2
×
The total conduction losses will be:
P CON(TOTAL) = P CON(UPPER) + P CON(LOWER)
P CON(TOTAL) = 0.85W
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
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-
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:
V DS(OFF)
T
Where:
V DS(OFF) = Drain to Source Voltage at off time
t r = Rise Time
t f = Fall Time
T = Switching Period
I LOAD = Load Current
The switching time waveform is shown in Figure 10.
V DS
90%
resistor (R SET ) from drain of low side MOSFET to the
OCSet pin. The resistor can be calculated by using equa-
tion (2).
The R DS(ON) has a positive temperature coefficient and it
should be considered for the worse case operation.
R DS(ON) = 8m ?× 1.5 = 12m ?
I SET ? I O(LIM) = 8A × 1.5 = 12A
(50% over nominal output current)
This results to:
R SET = 5.76K ?
Feedback Compensation
The IRU3039 is a voltage mode controller; the control
loop is a single voltage feedback path including error
amplifier and error comparator. To achieve fast transient
response and accurate output regulation, a compensa-
tion circuit is necessary. The goal of the compensation
network is to provide a closed loop transfer function with
the highest 0dB crossing frequency and adequate phase
margin (greater than 45 ).
The output LC filter introduces a double pole, –40dB/
decade gain slope above its corner resonant frequency,
and a total phase lag of 180 (see Figure 11). The Reso-
nant frequency of the LC filter is expressed as follows:
1
F LC = ---(13)
2 π× L O × C O
Figure 11 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.
10%
V GS
Gain
Phase
t d (ON)
t r
t d (OFF)
t f
0dB
-40dB/decade
0
Figure 10 - Switching time waveforms.
From IRF7466 data sheet we obtain:
IRF7466
F LC Frequency
-180
F LC
Frequency
t r = 2.8ns
t f = 3.6ns
10
www.irf.com
Figure 11 - Gain and phase of LC filter.
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| IRU3046 | 制造商:IRF 制造商全称:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER WITH CURRENT SHARING CIRCUITRY AND LDO CONTROLLER |
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| IRU3046CFTR | 功能描述:IC REG CTRLR BUCK PWM VM 24TSSOP RoHS:否 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 |
| IRU3046CFTRPBF | 制造商:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER WITH CURRENT SHARING CIRCUITRY AND LDO CONTROLLER |
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