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参数资料
| 型号： | ADP1878ACPZ-0.6-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 14LFCSP |
| 标准包装： | 1,500 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 600kHz |
| 占空比： | 65% |
| 电源电压： | 2.95 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： | 14-WFDFN 裸露焊盘，CSP |
| 包装： | 带卷 (TR) |
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Data Sheet
HS
REPEATED CURRENT-LIMIT
VIOLATION DETECTED
ADP1878/ADP1879
A PREDETERMINED NUMBER
SOFT START IS
CLIM
OF PULSES IS COUNTED TO REINITIALIZED TO
ALLOW THE CONVERTER MONITOR IF THE
TO COOL DOWN
VIOLATION
STILL EXISTS
ZERO
CURRENT
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 low-side MOSFET exceeds the current-
limit setpoint. When 32 current-limit violations are detected,
the controller enters idle mode and turns off the MOSFETs for
HS
t ON
6 ms, allowing the converter to cool down. Then, the controller
reestablishes soft start and begins to cause the output to ramp
LS
t OFF
HS AND LS ARE OFF
OR IN IDLE MODE
up again (see Figure 73). While the output ramps up, the current
sense 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.
I LOAD
0A
AS THE INDUCTOR
CURRENT APPROACHES
ZERO CURRENT, THE STATE
MACHINE TURNS OFF THE
LOWER-SIDE MOSFET.
SYNCHRONOUS RECTIFIER
The ADP1878 / ADP1879 employ internal MOSFET drivers for
the external high- and low-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 high-side driver input. This is beneficial
during startup to provide sufficient drive signal to the external
high-side MOSFET and to attain fast turn-on response, which is
essential for minimizing switching losses. The integrated high-
and low-side MOSFET drivers operate in complementary
fashion with built-in anti cross conduction circuitry to prevent
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 high- and low-
side switching activities when the inductor current approaches
the zero current line, causing the system to enter idle mode,
where the high- and low-side MOSFETs are turned off. To ensure
idle mode entry, a 10 mV offset, connected in series at the SW
ZERO-CROSS
COMPARATOR SW
I Q2
10mV
unwanted shoot through current that may potentially damage the
MOSFETs or reduce efficiency because of excessive power loss.
LS
Q2
ADP1879 POWER SAVING MODE (PSM)
A power saving mode is provided in the ADP1879 . The ADP1879
operates in the discontinuous conduction mode (DCM) and
pulse skips at light 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.
Figure 75. Zero-Cross Comparator with 10 mV of Offset
As soon as the forward current through the low-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 low-side MOSFET. From this point, the slope of the
as the body diode of the low-side MOSFET begins to conduct
current and continues conducting current until the remaining
energy stored in the inductor has been depleted.
Rev. B | Page 21 of 40
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| ADP1878ACPZ-1.0-R7 | 功能描述:IC REG CTRLR BUCK PWM CM 14LFCSP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 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:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| ADP1879-0.3-EVALZ | 功能描述:BOARD EVAL FOR ADP1879-0.3 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:* 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 |
| ADP1879-0.6-EVALZ | 功能描述:BOARD EVAL FOR ADP1879-0.6 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:* 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 |
| ADP1879-1.0-EVALZ | 功能描述:BOARD EVAL FOR ADP1879-1.0 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:* 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 |
| ADP1879ACPZ-0.3-R7 | 功能描述:IC REG CTRLR BUCK PWM CM 14LFCSP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 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:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
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