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參數(shù)資料
| 型號： | LM2832YSDX |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | High Frequency 2.0A Load - Step-Down DC-DC Regulator |
| 中文描述： | 3.25 A SWITCHING REGULATOR, 700 kHz SWITCHING FREQ-MAX, DSO6 |
| 封裝： | LLP-6 |
| 文件頁數(shù)： | 11/27頁 |
| 文件大?。?/td> | 895K |
| 代理商： | LM2832YSDX |
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Applications Information
THEORY OF OPERATION
The LM2832 is a constant frequency PWM buck regulator IC
that delivers a 2.0A load current. The regulator has a preset
switching frequency of 1.6MHz or 3.0MHz. This high fre-
quency allows the LM2832 to operate with small surface
mount capacitors and inductors, resulting in a DC/DC con-
verter that requires a minimum amount of board space. The
LM2832 is internally compensated, so it is simple to use and
requires few external components. The LM2832 uses
current-mode control to regulate the output voltage. The
following operating description of the LM2832 will refer to the
Simplified Block Diagram (Figure 1) and to the waveforms in
Figure 2. The LM2832 supplies a regulated output voltage by
switching the internal PMOS control switch at constant fre-
quency and variable duty cycle. A switching cycle begins at
the falling edge of the reset pulse generated by the internal
oscillator. When this pulse goes low, the output control logic
turns on the internal PMOS control switch. During this on-
time, the SW pin voltage (V
SW
) swings up to approximately
V
IN
, and the inductor current (I
L
) increases with a linear
slope. I
L
is measured by the current sense amplifier, which
generates an output proportional to the switch current. The
sense signal is summed with the regulator’s corrective ramp
and compared to the error amplifier’s output, which is pro-
portional to the difference between the feedback voltage and
V
. When the PWM comparator output goes high, the
output switch turns off until the next switching cycle begins.
During the switch off-time, inductor current discharges
through the Schottky catch diode, which forces the SW pin to
swing below ground by the forward voltage (V
) of the
Schottky catch diode. The regulator loop adjusts the duty
cycle (D) to maintain a constant output voltage.
SOFT-START
This function forces V
to increase at a controlled rate
during start up. During soft-start, the error amplifier’s refer-
ence voltage ramps from 0V to its nominal value of 0.6V in
approximately 600 μs. This forces the regulator output to
ramp up in a controlled fashion, which helps reduce inrush
current.
OUTPUT OVERVOLTAGE PROTECTION
The over-voltage comparator compares the FB pin voltage
to a voltage that is 15% higher than the internal reference
V
REF
. Once the FB pin voltage goes 15% above the internal
reference, the internal PMOS control switch is turned off,
which allows the output voltage to decrease toward regula-
tion.
UNDERVOLTAGE LOCKOUT
Under-voltage lockout (UVLO) prevents the LM2832 from
operating until the input voltage exceeds 2.73V (typ). The
UVLO threshold has approximately 430 mV of hysteresis, so
the part will operate until V
drops below 2.3V (typ). Hys-
teresis prevents the part from turning off during power up if
V
IN
is non-monotonic.
CURRENT LIMIT
The LM2832 uses cycle-by-cycle current limiting to protect
the output switch. During each switching cycle, a current limit
comparator detects if the output switch current exceeds
3.25A (typ), and turns off the switch until the next switching
cycle begins.
THERMAL SHUTDOWN
Thermal shutdown limits total power dissipation by turning
off the output switch when the IC junction temperature ex-
ceeds 165C. After thermal shutdown occurs, the output
switch doesn’t turn on until the junction temperature drops to
approximately 150C.
20197566
FIGURE 2. Typical Waveforms
L
www.national.com
11
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LM2832YSDX/NOPB | 功能描述:直流/直流開關調(diào)節(jié)器 RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| LM2832ZMY | 功能描述:直流/直流開關調(diào)節(jié)器 RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| LM2832ZMY EVAL | 功能描述:電源管理IC開發(fā)工具 LM2832 Eval Brd RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| LM2832ZMY | 制造商:Texas Instruments 功能描述:V REG 2A 3MHZ BUCK 2832 EMSOP8-8 |
| LM2832ZMY/NOPB | 功能描述:直流/直流開關調(diào)節(jié)器 RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
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