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參數(shù)資料
| 型號： | ADP1875ARQZ-0.3-R7 |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING CONTROLLER, 300 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封裝： | ROHS COMPLIANT, MO-137AB, QSOP-16 |
| 文件頁數(shù)： | 15/44頁 |
| 文件大小： | 2475K |
| 代理商： | ADP1875ARQZ-0.3-R7 |
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ADP1874/ADP1875
Rev. 0 | Page 22 of 44
HS
CLIM
ZERO
CURRENT
REPEATED CURRENT-LIMIT
VIOLATION DETECTED
A PREDETERMINED NUMBER
OF PULSES IS COUNTED TO
ALLOW THE CONVERTER
TO COOL DOWN
SOFT START IS
REINITIALIZED TO
MONITOR IF THE
VIOLATION
STILL EXISTS
09
34
7-
07
1
Figure 73. Idle Mode Entry Sequence Due to Current-Limit Violation
HICCUP MODE DURING SHORT CIRCUIT
A current-limit violation occurs when the current across the
source and drain of the lower-side MOSFET exceeds the current-
limit setpoint. When 16 current-limit violations are detected,
the controller enters idle mode and turns off the MOSFETs for
6 ms, allowing the converter to cool down. Then, the controller
reestablishes soft start and begins to cause the output to ramp up
again (see Figure 73). While the output ramps up, CS amplifier
output is monitored to determine if the violation is still present.
If it is still present, the idle event occurs again, followed by the full
chip, power-down sequence. This cycle continues until the
violation no longer exists. If the violation disappears, the converter
is allowed to switch normally, maintaining regulation.
SYNCHRONOUS RECTIFIER
The ADP1874/ADP1875 employ internal MOSFET drivers for
the external upper- and lower-side MOSFETs. The low-side
synchronous rectifier not only improves overall conduction
efficiency but it also ensures proper charging of the bootstrap
capacitor located at the upper-side driver input. This is beneficial
during startup to provide sufficient drive signal to the external
upper-side MOSFET and to attain fast turn-on response, which is
essential for minimizing switching losses. The integrated upper-
and lower-side MOSFET drivers operate in complementary
fashion with built-in anti cross-conduction circuitry to prevent
unwanted shoot-through current that may potentially damage the
MOSFETs or reduce efficiency because of excessive power loss.
ADP1875 POWER SAVING MODE (PSM)
A power saving mode is provided in the ADP1875. The ADP1875
operates in the discontinuous conduction mode (DCM) and
pulse skips at light load to medium load currents. The controller
outputs pulses as necessary to maintain output regulation. Unlike
the continuous conduction mode (CCM), DCM operation
prevents negative current, thus allowing improved system
efficiency at light loads. Current in the reverse direction through
this pathway, however, results in power dissipation and therefore
a decrease in efficiency.
HS
HS AND LS ARE OFF
OR IN IDLE MODE
LS
0A
ILOAD
AS THE INDUCTOR
CURRENT APPROACHES
ZERO CURRENT, THE STATE
MACHINE TURNS OFF THE
LOWER-SIDE MOSFET.
tON
tOFF
09
34
7-
07
2
Figure 74. Discontinuous Mode of Operation (DCM)
To minimize the chance of negative inductor current buildup,
an on-board zero-cross comparator turns off all upper- and
lower-side switching activities when the inductor current
approaches the zero current line, causing the system to enter
idle mode, where the upper- and lower-side MOSFETs are turned
off. To ensure idle mode entry, a 10 mV offset, connected in
series at the SW node, is implemented (see Figure 75).
10mV
ZERO-CROSS
COMPARATOR
Q2
LS
SW
IQ2
09
34
7-
07
3
Figure 75. Zero-Cross Comparator with 10 mV of Offset
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| ADP1875ARQZ-1.0-R7 | 功能描述:IC REG CTRLR BUCK PWM CM 16-QSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| ADP1876 | 制造商:AD 制造商全稱:Analog Devices 功能描述:600 kHz Dual Output Synchronous Buck |
| ADP1876ACPZ-R7 | 功能描述:IC REG CTRLR BUCK PWM CM 32LFCSP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 特色產(chǎn)品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標準包裝:1 系列:PowerWise® PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.5 V ~ 18 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-5°C ~ 125°C 封裝/外殼:32-WFQFN 裸露焊盤 包裝:Digi-Reel® 產(chǎn)品目錄頁面:1303 (CN2011-ZH PDF) 其它名稱:LM3754SQDKR |
| ADP1876-EVALZ | 功能描述:BOARD EVAL FOR ADP1876 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - DC/DC 與 AC/DC（離線）SMPS 系列:* 標準包裝:1 系列:- 主要目的:DC/DC，步降 輸出及類型:1，非隔離 功率 - 輸出:- 輸出電壓:3.3V 電流 - 輸出:3A 輸入電壓:4.5 V ~ 28 V 穩(wěn)壓器拓撲結構:降壓 頻率 - 開關:250kHz 板類型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名稱:497-12113STEVAL-ISA094V1-ND |
| ADP1877 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Dual Output Synchronous Buck PWM Controller With Tracking |
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