收藏本站
NCP3011, NCV3011
Trip:
Vsense > I trip Ref at 3/4 Point
No Trip:
Vsense < I trip Ref at 3/4 Point
Itrip Ref
Vsense
?
Ton ? 2
1/4
1/2
3/4 Point Determined by
Prior Cycle
?
Ton ? 1
1/4
1/2
Current Level 1
Current Level 2
3/4
Ton ? 1
Ton
3/4
Each switching cycle’s Ton is counted in 10 nS time steps. The 3/4 sample time
value is held and used for the following cycle’s limit sample time
Figure 37. I Limit Trip Point Description
Soft ? Start Current limit
During soft ? start the I SET value is doubled to allow for
inrush current to charge the output capacitance. The DAC
reference is set back to its normal value after soft ? start has
completed.
V SW Ringing
The I Limit block can lose accuracy if there is excessive
V SW voltage ringing that extends beyond the 1/2 point of the
high ? side transistor on ? time. Proper snubber design and
keeping the ratio of ripple current and load current in the
10 ? 30% range can help alleviate this as well.
Current Limit
A current limit trip results in completion of one switching
cycle and subsequently half of another cycle T on to account
for negative inductor current that might have caused
negative potentials on the output. Subsequently the power
MOSFETs are both turned off and a 4 soft ? start time period
wait passes before another soft ? start cycle is attempted.
Boost Clamp Functionality
The boost circuit requires an external capacitor connected
between the BST and V SW pins to store charge for supplying
the high and low ? side gate driver voltage. This clamp circuit
limits the driver voltage to typically 7.5 V when V IN > 9 V,
otherwise this internal regulator is in dropout and typically
V IN ? 1.25 V.
The boost circuit regulates the gate driver output voltage
and acts as a switching diode. A simplified diagram of the
boost circuit is shown in Figure 38. While the switch node
is grounded, the sampling circuit samples the voltage at the
boost pin, and regulates the boost capacitor voltage. The
sampling circuit stores the boost voltage while the V SW is
high and the linear regulator output transistor is reversed
biased.
VIN
8.9V
I ave vs Trip Point
The average load trip current versus R SET value is shown
the equation below:
Switch
Sampling
Circuit
BST
I AveTRIP +
I set R set
R DS(on)
*
1 V IN * V OUT
4 L
V OUT
V IN
1
F SW
VSW
LSDR
(eq. 5)
Where:
L = Inductance (H)
I SET = 13 m A
R SET = Gate to Source Resistance ( W )
R DS(on) = On Resistance of the HS MOSFET ( W )
V IN = Input Voltage (V)
V OUT = Output Voltage (V)
F SW = Switching Frequency (Hz)
http://onsemi.com
18
Figure 38. Boost Circuit
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
MIC2505BM IC SW HIGH SIDE SGL 2A 8SOIC
MIC2505-2BM IC SW HIGH SIDE SGL 2A 8SOIC
MIC2505-1BM IC SW HIGH SIDE SGL 2A 8SOIC
TAAB106K020G CAP TANT 10UF 20V 10% AXIAL
MC34063LBBEVB EVAL BOARD FOR MC34063LBB
A9BAG-0502F FLEX CABLE - AFF05G/AF05/AFE05T
EBM08DTMD-S189 CONN EDGECARD 16POS R/A .156 SLD
RCM06DSUI CONN EDGECARD 12POS DIP .156 SLD
相关代理商/技术参数
NCP3012 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Synchronous PWM Controller
NCP3012DTBR2G 功能描述:电压模式 PWM 控制器 Single Output Buck 0.8V to 40V 70uA RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel
NCP301HSN09T1 功能描述:电压监测器/监控器 0.9V Detector RoHS:否 制造商:Texas Instruments 监测电压数:2 监测电压:Adjustable 输出类型:Open Drain 欠电压阈值: 过电压阈值: 准确性:1 % 工作电源电压:1.5 V to 6.5 V 工作电源电流:1.8 uA 最大工作温度:+ 125 C 封装 / 箱体:SON-6 安装风格:SMD/SMT
NCP301HSN09T1G 功能描述:电压监测器/监控器 0.9V Detector w/Reset High RoHS:否 制造商:Texas Instruments 监测电压数:2 监测电压:Adjustable 输出类型:Open Drain 欠电压阈值: 过电压阈值: 准确性:1 % 工作电源电压:1.5 V to 6.5 V 工作电源电流:1.8 uA 最大工作温度:+ 125 C 封装 / 箱体:SON-6 安装风格:SMD/SMT
NCP301HSN10T1 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Voltage Detector Series
NCP301HSN11T1 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Voltage Detector Series
NCP301HSN12T1 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Voltage Detector Series
NCP301HSN13T1 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Voltage Detector Series