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参数资料
| 型号： | NCP3125CRAGEVB |
| 厂商： | ON Semiconductor |
| 文件页数： | 13/22页 |
| 文件大小： | 0K |
| 描述： | BOARD EVALUATION NCP3125 CERAMIC |
| 设计资源： | NCP3125 Schematic NCP3125CRAGEVB BOM |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 最低可调至 0.8V |
| 电流 - 输出： | 4A |
| 输入电压： | 4.5 ~ 13.2 V |
| 稳压器拓扑结构： | 降压 |
| 频率 - 开关： | 350kHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | NCP3125 |
| 其它名称： | NCP3125CRAGEVBOS |
NCP3125
When calculating the rise time and fall time of the high side
MOSFET it is important to know the charge characteristic
shown in Figure 22.
F SW = Switching frequency
P RR = High side MOSFET reverse recovery losses
Q RR = Reverse recovery charge
V IN = Input voltage
The low ? side MOSFET turns on into small negative
voltages so switching losses are negligible. The low ? side
MOSFET’s power dissipation only consists of conduction
loss due to R DS(on) and body diode loss during the
non ? overlap periods.
Vth
P D_LS + P COND ) P BODY
(eq. 30)
P BODY = Low side MOSFET body diode losses
P COND = Low side MOSFET conduction losses
P D_LS = Low side MOSFET losses
Conduction loss in the low ? side MOSFET is described as
follows:
I G1
I G2
P COND + I RMS_LS
@ R DS(on)_LS
(1 * D) @ 1 ) ra
I RMS_LS + I OUT @
P DS + 1 @ C OSS @ V IN @ F SW
(eq. 28)
Figure 22. MOSFET Switching Characteristics
Q GD Q GD
t RISE + + (eq. 26)
V BST * V TH R HSPU ) R G
I G1 = Output current from the high ? side gate
drive
Q GD = MOSFET gate to drain gate charge
R HSPU = Drive pull up resistance
R G = MOSFET gate resistance
t RISE = MOSFET rise time
V BST = Boost voltage
V TH = MOSFET gate threshold voltage
Q GD Q GD
t FALL + + (eq. 27)
V BST * V TH R HSPD ) R G
I G2 = Output current from the low ? side gate drive
Q GD = MOSFET gate to drain gate charge
R G = MOSFET gate resistance
R HSPD = Drive pull down resistance
t FALL = MOSFET fall time
V BST = Boost voltage
V TH = MOSFET gate threshold voltage
Next, the MOSFET output capacitance losses are caused
by both the high ? side and low ? side MOSFETs, but are
dissipated only in the high ? side MOSFET.
2
2
C OSS = MOSFET output capacitance at 0V
F SW = Switching frequency
P DS = MOSFET drain to source charge losses
V IN = Input voltage
Finally, the loss due to the reverse recovery time of the
body diode in the low ? side MOSFET is shown as follows:
P RR + Q RR @ V IN @ F SW (eq. 29)
2
(eq. 31)
I RMS_LS = RMS current in the low side
R DS(on)_LS = Low ? side MOSFET on resistance
P COND = High side MOSFET conduction losses
2
(eq. 32)
12
D = Duty ratio
I OUT = Load current
I RMS_LS = RMS current in the low side
ra = Ripple current ratio
The body diode losses can be approximated as:
P BODY + V FD @ I OUT @ F SW @ NOL LH ) NOL HL (eq. 33)
F SW = Switching frequency
I OUT = Load current
NOL HL = Dead time between the high ? side
MOSFET turning off and the low ? side
MOSFET turning on, typically 50 ns
NOL LH = Dead time between the low ? side
MOSFET turning off and the high ? side
MOSFET turning on, typically 50 ns
P BODY = Low ? side MOSFET body diode losses
V FD = Body diode forward voltage drop
Control Dissipation
The control portion of the IC power dissipation is
determined by the formula below:
P C + I CC V IN (eq. 34)
I CC = Control circuitry current draw
P C = Control power dissipation
V IN = Input voltage
Once the IC power dissipations are determined, the
designer can calculate the required thermal impedance to
maintain a specified junction temperature at the worst case
http://onsemi.com
13
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相关代理商/技术参数 |
参数描述 |
|---|---|
| NCP3126ADR2G | 功能描述:直流/直流开关转换器 3A PWM Switching Buck Regulator RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| NCP3126AGEVB | 功能描述:电源管理IC开发工具 NCP3126 EVB RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| NCP3126CRAGEVB | 功能描述:电源管理IC开发工具 NCP3126 CERAMIC EVB RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| NCP3127ADR2G | 功能描述:直流/直流开关转换器 2A PWM Switching Buck Regulator RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| NCP3127AGEVB | 功能描述:电源管理IC开发工具 NCP3127 EVALUATION BOARD RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
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