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| 型号： | IRU3038CF |
| 厂商： | International Rectifier |
| 文件页数： | 4/18页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM TSSOP14 |
| 标准包装： | 94 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 440kHz |
| 占空比： | 95% |
| 电源电压： | 5 V ~ 12 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： | 14-TSSOP（0.173"，4.40mm 宽） |
| 包装： | 管件 |
| 产品目录页面： | 1384 (CN2011-ZH PDF) |
| 其它名称： | *IRU3038CF |
IRU3038
BLOCK DIAGRAM
V REF 3
1.25V
3V
Vcc
4V
Vc
0.25V
0.2V
Bias
Generator
3V
1.25V
POR
11 R t
20uA
3.5V
10 V c
SS 13
64uA Max
Rt
Ct
Oscillator
9 HDrv
POR
Error Comp
S
Q
V P 2
25K
Error Amp
R
4
Vcc
25K
Reset Dom
Fb 1
C o m p 12
0.6V
FbLo Comp
POR
6
8
7
LDrv
PGnd
Gnd
Figure 2 - Simplified block diagram of the IRU3038.
THEORY OF OPERATION
Introduction
The IRU3038 is a fixed frequency, voltage mode syn-
chronous controller and consists of a precision refer-
ence voltage, an uncommitted error amplifier, an internal
oscillator, a PWM comparator, 0.5A peak gate driver,
soft-start and shutdown circuits (see Block Diagram).
The output voltage of the synchronous converter is set
and controlled by the output of the error amplifier; this is
the amplified error signal from the sensed output voltage
and the voltage on non-inverting input of error amplifier(V P ).
This voltage is compared to a fixed frequency linear
sawtooth ramp and generates fixed frequency pulses of
variable duty-cycle, which drives the two N-channel ex-
ternal MOSFETs.
The timing of the IC is provided through an internal oscil-
lator circuit which uses on-chip capacitor. The oscilla-
tion frequency is programmable between 200 to 400KHz
by using an external resistor. Figure 12 shows switch-
ing frequency vs. external resistor (Rt).
Soft-Start
The IRU3038 has a programmable soft-start to control
the output voltage rise and limit the current surge at the
start-up. To ensure correct start-up, the soft-start se-
quence initiates when the Vc and Vcc rise above their
threshold (3.3V and 4.2V respectively) and generates
the Power On Reset (POR) signal. Soft-start function
operates by sourcing an internal current to charge an
external capacitor to about 3V. Initially, the soft-start func-
tion clamps the E/A’s output of the PWM converter. As
the charging voltage of the external capacitor ramps up,
the PWM signals increase from zero to the point the
feedback loop takes control.
Short-Circuit Protection
The outputs are protected against the short-circuit. The
IRU3038 protects the circuit for shorted output by sens-
ing the output voltage (through the external resistor di-
vider). The IRU3038 shuts down the PWM signals, when
the output voltage drops below 0.6V.
The IRU3038 also protects the output from over-voltaging
when the control FET is shorted. This is done by turning
on the sync FET with the maximum duty cycle.
Under-Voltage Lockout
The under-voltage lockout circuit assures that the
MOSFET driver outputs remain in the off state whenever
the supply voltage drops below set parameters. Lockout
occurs if Vc and Vcc fall below 3.3V and 4.2V respec-
tively. Normal operation resumes once Vc and Vcc rise
above the set values.
4
www.irf.com
Rev. 2.0
09/12/02
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相关代理商/技术参数 |
参数描述 |
|---|---|
| IRU3038CFTRPBF | 制造商:International Rectifier 功能描述:Voltage Mode PWM Controller 500mA 14-Pin TSSOP T/R |
| IRU3038CS | 功能描述:IC REG CTRLR BUCK PWM VM 14-SOIC 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:2,000 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:50% 电源电压:9 V ~ 10 V 降压:无 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:-40°C ~ 85°C 封装/外壳:8-TSSOP（0.173"，4.40mm 宽） 包装:带卷 (TR) |
| IRU3038CSTR | 功能描述:IC REG CTRLR BUCK PWM VM 14-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 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:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| IRU3039 | 制造商:IRF 制造商全称:International Rectifier 功能描述:SYNCHRONOUS PWM CONTROLLER WITH OVER CURRENT PROTECTION |
| IRU3039CH | 制造商:IRF 制造商全称:International Rectifier 功能描述:SYNCHRONOUS PWM CONTROLLER WITH OVER CURRENT PROTECTION |
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