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参数资料
| 型号： | IR3876MTRPBF |
| 厂商： | International Rectifier |
| 文件页数： | 11/21页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 12A 17QFN |
| 产品培训模块： | SupIRBuck? Family and POL Design Tools Overview |
| 标准包装： | 4,000 |
| 系列： | SupIRBuck™ |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.5 V ~ 12 V |
| 输入电压： | 3 V ~ 21 V |
| 频率 - 开关： | 可调至 1MHz |
| 电流 - 输出： | 12A |
| 同步整流器： | 是 |
| 工作温度： | 0°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 17-PowerVQFN |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | PQFN（5x6） |
IR3876MPBF
CIRCUIT DESCRIPTION
PWM COMPARATOR
The PWM comparator initiates a SET signal
(PWM pulse) when the FB pin falls below the
reference (Vref) or the soft start (SS) voltage.
PGOOD
The PGOOD pin is open drain and it needs to
be externally pulled high. High state indicates
that output is in regulation. The PGOOD logic
monitors
EN_DELAY,
SS_DELAY,
and
ON-TIME GENERATOR
under/over voltage fault signals. PGOOD is
The PWM on-time duration is programmed with
released
only
when
EN_DELAY
and
an external resistor (R FF ) from the input supply
(VIN) to the FF pin. The simplified calculation for
R FF is shown in equation 1. The FF pin is held to
an internal reference after EN goes HIGH. A copy
of the current in R FF charges a timing capacitor,
SS_DELAY = HIGH and output voltage is within
the OV and UV thresholds.
PRE-BIAS STARTUP
IR3876 is able to start up into pre-charged
which sets the on-time duration, as shown in
output,
which
prevents
oscillation
and
equation 2.
disturbances of the output voltage.
R FF ?
T ON ?
V OUT
1 V ? 20 pF ? F SW
R FF ? 1 V ? 20 pF
V IN
(1)
(2)
With constant on-time control, the output
voltage is compared with the soft start voltage
(SS) or Vref, depending on which one is lower,
and will not start switching unless the output
voltage drops below the reference. This scheme
prevents discharge of a pre-biased output
CONTROL LOGIC
The control logic monitors input power sources,
sequences the converter through the soft-start
and protective modes, and initiates an internal
RUN signal when all conditions are met.
VCC and 3VCBP pins are continuously monitored,
and the IR3876 will be disabled if the voltage of
either pin drops below the falling thresholds.
EN_DELAY will become HIGH when VCC and
3VCBP are in the normal operating range and the
EN pin = HIGH.
SOFT START
With EN = HIGH, an internal 10μA current source
charges the external capacitor (C SS ) on the SS pin
to set the output voltage slew rate during the soft
start interval. The soft start time (t SS ) can be
calculated from equation 3.
voltage.
SHUTDOWN
The IR3876 will shutdown if VCC is below its
UVLO limit. The IR3876 can be shutdown by
pulling the EN pin below its lower threshold.
Alternatively, the output can be shutdown by
pulling the soft start pin below 0.3V.
t SS ?
C SS ? 0.5 V
10 ? A
(3)
The feedback voltage tracks the SS pin until SS
reaches the 0.5V reference voltage (Vref), then
feedback is regulated to Vref. C SS will continue to
be charged, and when SS pin reaches V SS (see
Figure 17. Normal Startup
Electrical Specification ), SS_DELAY goes HIGH.
With EN_DELAY = LOW, the capacitor voltage
and SS pin is held to the FB pin voltage. A normal
startup sequence is shown in Figure 17.
11
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相关代理商/技术参数 |
参数描述 |
|---|---|
| IR3876TR1PBF | 制造商:IRF 制造商全称:International Rectifier 功能描述:12A HIGHLY INTEGRATED WIDE-INPUT VOLTAGE, SYNCHRONOUS BUCK REGULATOR |
| IR3891 | 制造商:IRF 制造商全称:International Rectifier 功能描述:Dual output, 4A/Phase, Highly Integrated SupIRBuck |
| IR3891MPBF | 制造商:IRF 制造商全称:International Rectifier 功能描述:Dual output, 4A/Phase, Highly Integrated SupIRBuck |
| IR3891MTR1PBF | 功能描述:直流/直流开关调节器 4A Phase Dual Reg Single 5V to 21V PWM RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量:2 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:PQFN 5 x 6 |
| IR3891MTRPBF | 制造商:International Rectifier 功能描述:Dual Output 4 A/Phase 1 to 21 V 1.5 MHz Synchronous Buck Regulator-PQFN 5 x 6 mm |
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