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参数资料
| 型号： | IRDC3822 |
| 厂商： | International Rectifier |
| 文件页数： | 8/21页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL SYNC BUCK CONVERTER |
| 产品变化通告： | (EP) Parts Discontinuation 25/May/2012 |
| 标准包装： | 1 |
| 系列： | * |
PD-60333
IR3822MPBF
Circuit Description
THEORY OF OPERATION
The IR3822 is a voltage mode PWM
synchronous regulator and operates with a fixed
600kHz switching frequency, allowing the use of
small external components.
The output voltage is set by feedback pin (Fb)
and the internal reference voltage (0.6V). These
are two inputs to error amplifier. The error signal
between these two inputs is amplified and it is
compared to a fixed frequency linear sawtooth
ramp.
A trailing edge modulation is used for generating
fixed frequency pulses (PWM) which drives the
internal N-channel MOSFETs.
The internal oscillator circuit uses on-chip
circuitry, eliminating the need for external
Pre-Bias Startup
The IR3822 is able to start up into pre-charged
output, which prevents oscillation and
disturbances of the output voltage.
The output starts in asynchronous fashion and
keeps the synchronous MOSFET off until the first
gate signal for control MOSFET is generated.
Figure 4 shows a typical Pre-Bias condition at
start up.
Depending on system configuration, a specific
amount of output capacitors may be required to
prevent discharging the output voltage.
components.
The IR3822 operates with single input voltage
from 4.5V to 14V allowing an extended operating
input voltage range.
The over-current protection is performed by
sensing current through the R DS(on) of low side
MOSFET. This method enhances the converter’s
efficiency and reduces cost by eliminating a
current sense resistor. The current limit is
V
Pre-Bias Voltage
Vo
Time
programmable by using an external resistor.
Fig. 4: Pre-Bias start up
Under-Voltage Lockout
The under-voltage lockout circuit monitors the
two input supplies (Vcc and Vc) and assures that
the MOSFET driver outputs remain in the off
state whenever the supply voltage drops below
set thresholds. Lockout occurs if Vcc or Vc fall
below 4.3V and 3.3V respectively. Normal
operation resumes once Vcc and Vc rise above
the set values.
Thermal Shutdown
Temperature sensing is provided inside the
IR3822. The trip threshold is typically set to
140 o C. When trip threshold is exceeded, thermal
shutdown turns off both MOSFETs. Thermal
shutdown is not latched and automatic restart is
initiated when the sensed temperature drops
within the operating range. There is a 20 o C
hysteresis in the thermal shutdown threshold.
11/04/08
Shutdown
The output can be shutdown by pulling the soft-
start pin below 0.3V. This can easily be done by
using an external small signal transistor. During
shutdown both MOSFET drivers will be turned
off. Normal operation will resume by cycling soft
start pin.
Power Good
The IR3822 provides an open collector power
good signal which reports the status of the
output. The output is sensed through the
dedicated Vsns pin. The power good threshold
can be externally programmed using two external
resistors. The power good comparator is
internally set to 0.38V (typical).
8
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相关代理商/技术参数 |
参数描述 |
|---|---|
| IRDC3822A | 功能描述:电源管理IC开发工具 IR3822A SYNC CONV 300kHz EVAL BRD 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 |
| IRDC3823 | 制造商:International Rectifier 功能描述:IRDC3823 Eval Board for IR3823 SupIRBuck Single-Input Voltage, Synchronous Buck 制造商:International Rectifier 功能描述:Power Management IC Development Tools Demokit IR3823M Dev Board |
| IRDC3831 | 功能描述:电源管理IC开发工具 IR3831 SYNC CONV 600kHz EVAL BRD 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 |
| IRDC3831W | 功能描述:电源管理IC开发工具 User Guide IR3831W Eval Brd 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 |
| IRDC3832W | 功能描述:电源管理IC开发工具 User Guide IR3832W Eval Brd 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 |
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