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参数资料
| 型号： | ADP1872ARMZ-1.0-R7 |
| 厂商： | Analog Devices Inc |
| 文件页数： | 21/40页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 10-MSOP |
| 标准包装： | 1 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1MHz |
| 占空比： | 45% |
| 电源电压： | 3 V ~ 20 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： | -40°C ~ 125°C |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 包装： | 标准包装 |
| 产品目录页面： | 792 (CN2011-ZH PDF) |
| 其它名称： | ADP1872ARMZ-1.0-R7DKR |
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Data Sheet
SYNCHRONOUS RECTIFIER
The ADP1872/ADP1873 employ an internal lower side MOSFET
driver to drive the external upper side and lower side MOSFETs.
The synchronous rectifier not only improves overall conduction
efficiency but also ensures proper charging to 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 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 anticross conduction circuitry to prevent
unwanted shoot-through current that may potentially damage the
ADP1872/ADP1873
As soon as the forward current through the lower side MOSFET
decreases to a level where
10 mV = I Q2 × R ON(Q2)
the zero-cross comparator (or I REV comparator) emits a signal to
turn off the lower side MOSFET. From this point, the slope of the
as the body diode of the lower side MOSFET begins to conduct
current and continues conducting current until the remaining
energy stored in the inductor has been depleted.
ANOTHER t ON EDGE IS
TRIGGERED WHEN V OUT
FALLS BELOW REGULATION
MOSFETs or reduce efficiency as a result of excessive power loss.
POWER SAVING MODE (PSM) VERSION (ADP1873)
The power saving mode version of the ADP1872 is the ADP1873.
The ADP1873 operates in the discontinuous conduction mode
(DCM) and pulse skips at light load to midload currents. It
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.
SW
LS
I LOAD
0A
t ON
HS AND LS
IN IDLE MODE
ZERO-CROSS COMPARATOR
DETECTS 10mV OFFSET AND
TURNS OFF LS
10mV = R ON × I LOAD
HS
t ON
Figure 75. 10 mV Offset to Ensure Prevention of Negative Inductor Current
The system remains in idle mode until the output voltage drops
below regulation. A PWM pulse is then produced, turning on the
upper side MOSFET to maintain system regulation. The ADP1873
LS
t OFF
HS AND LS ARE OFF
OR IN IDLE MODE
does not have an internal clock; therefore, it switches purely as a
hysteretic controller, as described in this section.
TIMER OPERATION
The ADP1872/ADP1873 employ a constant on-time architecture,
I LOAD
0A
AS THE INDUCTOR
CURRENT APPROACHES
ZERO CURRENT, THE STATE
MACHINE TURNS OFF THE
LOWER SIDE MOSFET.
which provides a variety of benefits, including improved load
and line transient response when compared with a constant
(fixed) frequency current-mode control loop of comparable
loop design. The constant on-time timer, or t ON timer, senses
Figure 73. Discontinuous Mode of Operation (DCM)
To minimize the chance of negative inductor current buildup,
an on-board, zero-cross comparator turns off all upper side
and lower side switching activities when the inductor current
approaches the zero current line, causing the system to enter
the high input voltage (VIN) and the output voltage (V OUT ) using
SW waveform information to produce an adjustable one-shot
PWM pulse that varies the on-time of the upper side MOSFET in
response to dynamic changes in input voltage, output voltage, and
load current conditions to maintain regulation. It then generates
an on-time (t ON ) pulse that is inversely proportional to V IN .
idle mode, where the upper side and lower side MOSFETs are
turned off. To ensure idle mode entry, a 10 mV offset, connected
t ON ? K ?
V OUT
VIN
ZERO-CROSS
COMPARATOR
SW
I Q2
where K is a constant that is trimmed using an RC timer product
for the 300 kHz, 600 kHz, and 1.0 MHz frequency options.
10mV
LS
Q2
Figure 74. Zero-Cross Comparator with 10 mV of Offset
Rev. B | Page 21 of 40
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP1872-BL1-EVZ | 功能描述:EVAL BOARD FOR ADP1872 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 标准包装:1 系列:- 主要目的:DC/DC，步降 输出及类型:1，非隔离 功率 - 输出:- 输出电压:3.3V 电流 - 输出:3A 输入电压:4.5 V ~ 28 V 稳压器拓扑结构:降压 频率 - 开关:250kHz 板类型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名称:497-12113STEVAL-ISA094V1-ND |
| ADP1872-BL2-EVZ | 功能描述:EVAL BOARD FOR ADP1872 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 标准包装:1 系列:- 主要目的:DC/DC，步降 输出及类型:1，非隔离 功率 - 输出:- 输出电压:3.3V 电流 - 输出:3A 输入电压:4.5 V ~ 28 V 稳压器拓扑结构:降压 频率 - 开关:250kHz 板类型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名称:497-12113STEVAL-ISA094V1-ND |
| ADP1873-0.3-EVALZ | 功能描述:BOARD EVAL FOR ADP1873-0.3 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:* 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| ADP1873-0.6-EVALZ | 功能描述:BOARD EVAL FOR ADP1873-0.6 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:* 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| ADP1873-1.0-EVALZ | 功能描述:BOARD EVAL FOR ADP1873-1.0 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:* 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
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