- 您现在的位置：买卖IC网 > PDF目录17253 > IRDC3629 (International Rectifier)BOARD EVAL SYNC BUCK CONTROLLER PDF资料下载
参数资料
| 型号： | IRDC3629 |
| 厂商： | International Rectifier |
| 文件页数： | 9/23页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL SYNC BUCK CONTROLLER |
| 标准包装： | 1 |
| 系列： | * |
IR3629/IR3629A MPbF
Soft-Start
40uA
The IR3629/29A has a programmable soft-start
to control the output voltage rise and limit the
inrush current during start-up.
To ensure correct start-up, the soft-start
sequence initiates when Vcc and Vc rise above
their threshold and generate the Power On
Ready (POR) signal. The soft-start function
20uA
SS/SD
POR
3V
35uA
operates by sourcing current to charge an
external capacitor to about 3V.
Initially, the soft-start function clamps the output
of error amplifier by injecting a current (35uA)
into the Fb pin and generates a voltage about
0.84V (35ux24K) across the negative input of
Comp
0.6V
Fb
24K
24K
Error Amp
error amplifier (see figure 5).
The magnitude of the injected current is inversely
proportional to the voltage at the soft-start pin. As
the soft-start voltage ramps up, the injected
current decreases linearly and so does the
voltage at the negative input of error amplifier.
When the soft-start capacitor voltage is around
1V, the voltage at the positive input of the error
Fig. 5: Soft-Start circuit for IR3629/29A
amplifier is approximately 0.6V.
The output of the error amplifier will start
increasing and generating the first PWM signal.
As the soft-start capacitor voltage continues to
Output of UVLO
POR
3V
? 2V
40uA
rise up, the current flowing into the Fb pin will
keep decreasing.
The feedback voltage increases linearly as the
soft-start voltage ramps up. When soft-start
voltage is around 2V the output voltage reaches
Soft-Start
Voltage
Current flowing
into Fb pin
0V
35uA
0uA
? 1V
Voltage at negative input ? 0.96V
the steady state and the injected current is zero.
Figure 6 shows the theoretical operating
waveforms during soft-start.
The output voltage start-up time is the time
period when soft-start capacitor voltage
of Error Amp
0.84V
0.6V
0.6V
increases from 1V to 2V.
The start-up time will be dependent on the size of
Voltage at Fb pin
0V
the external soft-start capacitor and can be
estimated by:
Fig. 6: Theoretical operation waveforms
20 μ A ?
T start
C ss
= 2 V ? 1 V
during soft-start
For a given start-up time, the soft-start capacitor
(nF) can be estimated as:
C SS ? 20 μ A * T start ( ms )
11/29/2007
--( 1 )
9
相关PDF资料 |
PDF描述 |
|---|---|
| CGRM4001-HF | RECTIFIER 50V 1A SOD-123 |
| HK1608R39J-T | INDUCTOR HI FREQ 390NH 5% 0603 |
| CBC2012T470K | INDUCTOR 47UH 10% 0805 SMD |
| HK16083N3S-T | INDUCTOR HI FREQ 3.3+/-0.3NH |
| CBC2012T220K | INDUCTOR 22UH 10% 0805 SMD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| IRDC3629A | 功能描述:电源管理IC开发工具 IR3629A Eval BRD 300kHz 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 |
| IRDC3637 | 功能描述:电源管理IC开发工具 250kHz to 9MHz IR350B Xphase 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 |
| 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 |
发布紧急采购，3分钟左右您将得到回复。