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参数资料
| 型号： | ADP1871-0.6-EVALZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 20/44页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR ADP1871-0.6 |
| 标准包装： | 1 |
| 系列： | * |
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ADP1870/ADP1871
VIN and VREG be tied together if the VIN pin is subjected to a
Data Sheet
2.75 V rail.
Table 5. Power Input and LDO Output Configurations
CS
AMP
SW
PGND
VIN
VREG
Comments
CS GAIN SET
ADC
0.4V
>5.5 V
<5.5 V
<5.5 V
Float
Connect to VIN
Float
Must use the LDO
LDO drop voltage is not
realized (that is, if V IN =
2.75 V, then V REG = 2.75 V)
LDO drop is realized
DRVL
Ranges above
and below 5.5 V
Float
LDO drop is realized,
minimum V IN recom-
mendation is 2.95 V
RES
Figure 69. RES Detect Circuit for Current-Sense Gain Programming
Table 6. Current-Sense Gain Programming
THERMAL SHUTDOWN
The thermal shutdown is a self-protection feature to prevent the
IC from damage due to a very high operating junction temperature.
If the junction temperature of the device exceeds 155°C, the part
enters the thermal shutdown state. In this state, the device shuts off
Resistor
47 kΩ
22 kΩ
Open
100 kΩ
A CS
3 V/V
6 V/V
12 V/V
24 V/V
I CLIM ? I LOAD ? ? ? 1 ?
K I ?
?
2 ?
both the upper- and lower-side MOSFETs and disables the entire
controller immediately, thus reducing the power consumption of
the IC. The part resumes operation after the junction temperature
of the part cools to less than 140°C.
PROGRAMMING RESISTOR (RES) DETECT CIRCUIT
Upon startup, one of the first blocks to become active is the RES
detect circuit. This block powers up before soft start begins. It
and is programmed to identify four possible resistor values: 47 kΩ,
22 kΩ, open, and 100 kΩ.
The RES detect circuit digitizes the value of the resistor at the
DRVL pin (Pin 6). An internal ADC outputs a 2-bit digital code
that is used to program four separate gain configurations in the
current-sense amplifier (see Figure 69). Each configuration corre-
sponds to a current-sense gain (A CS ) of 3 V/V, 6 V/V, 12 V/V,
24 V/V, respectively (see Table 6 and Table 7). This variable is used
for the valley current-limit setting, which sets up the appropriate
current-sense gain for a given application and sets the compensation
necessary to achieve loop stability (see the Valley Current-Limit
Setting and Compensation Network sections).
VALLEY CURRENT-LIMIT SETTING
The architecture of the ADP1870/ADP1871 is based on valley
current-mode control. The current limit is determined by three
components: the R ON of the lower-side MOSFET, the error ampli-
fier output voltage swing (COMP), and the current-sense gain.
The COMP range is internally fixed at 1.4 V. The current-sense
gain is programmable via an external resistor at the DRVL pin (see
the Programming Resistor (RES) Detect Circuit section). The
R ON of the lower-side MOSFET can vary over temperature and
usually has a positive T C (meaning that it increases with tempera-
ture); therefore, it is recommended to program the current-sense
gain resistor based on the rated R ON of the MOSFET at 125°C.
Because the ADP1870/ADP1871 are based on valley current
control, the relationship between I CLIM and I LOAD is as follows:
?
where:
K I is the ratio between the inductor ripple current and the
ADP1870/
ADP1871
DRVH
SW
Q1
I CLIM is the desired valley current limit.
I LOAD is the current load.
Establishing K I helps to determine the inductor value (see the
Q2
DRVL
CS GAIN
PROGRAMMING
R RES
RIPPLE CURRENT =
I LOAD
3
Figure 68. Programming Resistor Location
Rev. B | Page 20 of 44
LOAD CURRENT
VALLEY CURRENT LIMIT
Figure 70. Valley Current Limit to Average Current Relation
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| ADP1871-1.0-EVALZ | 功能描述:BOARD EVAL FOR ADP1871-1.0 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 |
| ADP1871ACPZ-0.3-R7 | 功能描述:IC REG CTRLR BUCK PWM CM 10LFCSP 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) |
| ADP1871ACPZ-0.6-R7 | 功能描述:IC REG CTRLR BUCK PWM CM 10LFCSP 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) |
| ADP1871ACPZ-1.0-R7 | 功能描述:IC REG CTRLR BUCK PWM CM 10LFCSP 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) |
| ADP1871ARMZ-0.3-R7 | 功能描述:IC REG CTRLR BUCK PWM CM 10-MSOP 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) |
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