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参数资料
| 型号： | NCP3121QPBCKGEVB |
| 厂商： | ON Semiconductor |
| 文件页数： | 18/41页 |
| 文件大小： | 0K |
| 描述： | EVAL BOARD FOR NCP3121QPBCKG |
| 设计资源： | NCP3121 EVB BOM NCP3121QPBCKGEVB Gerber Files NCP3121QPBCKGEVB Schematic |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 2，非隔离 |
| 输出电压： | 3.3V，5V |
| 电流 - 输出： | 3A，3A |
| 输入电压： | 12V |
| 稳压器拓扑结构： | 降压 |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | NCP3121 |
| 其它名称： | NCP3121QPBCKGEVBOS |
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NCP3121
Output Voltage Programming
The controller will maintain 0.8 V at the feedback pin.
Thus, if a resistor divider circuit is placed across the
Table 4. Output Voltage Setting
feedback pin to V OUT , the controller will regulate the output
voltage in proportion to the resistor divider network in order
to maintain 0.8 V at the FB pin.
V OUT [V]
R 1 [k W ]
R 2 [k W ]
8
180
20
7.5
360
43
6
130
20
5
68
13
4
300
75
3.3
47
15
2.5
51
24
1.8
20
16
1.2
10
20
V OUT
R1
V FB
R2
Figure 36. Feedback divider
The relationship between the resistor divider network and
the output voltage is shown in the following equation:
frequency operation because a higher frequency results in
lower efficiency due to MOSFET gate charge losses.
Additionally, the use of smaller inductors at higher
frequencies results in higher ripple current, higher output
voltage ripple, and lower efficiency at light load currents.
The value of the oscillator resistor is designed to be linearly
related to the switching period. There are two ways to
determine the RT resistor value: by using the standard curve
shown in Figure 37 or by using Table 5. The frequency on
the RT pin will set the master oscillator. The actual operating
frequency on each channel will be one ? half the master
oscillator.
R 2 + R 1
V REF
V OUT * V REF
600
where:
V REF is the circuit’s internal voltage reference, which
equals 0.8 V.
Resistor R1 is selected based on a design trade ? off
between efficiency and output voltage accuracy. For high
values of R1, there is less current consumption in the
feedback network. However, the trade ? off is output voltage
accuracy due to the bias current in the error amplifier. Once
R1 has been determined, R2 can be calculated.
Selecting the Switching Frequency
500
400
300
200
100
Selecting the switching frequency is a trade ? off between
component size and power losses. Operation at higher
switching frequencies allows the use of smaller inductor and
capacitor values. Nevertheless, it is common to select lower
Table 5. Switching Frequency Selection
0
200 250 300 350 400 450 500 550 600 650 700 750
freq [kHz]
Figure 37. Switching Frequency Selection
Freq. [kHz]
RT [k W ]
200
open
250
649
300
316
350
205
400
154
450
121
500
100
550
84.5
600
73.2
650
64.9
700
57.6
750
52.3
Sequencing of Output Voltages
Some microprocessors and DSP chips need two power
supplies with different voltage levels. These systems often
require voltage sequencing between the core power supply
and the I/O power supply. Without proper sequencing,
latch ? up failure or excessive current draw may occur that
could result in damage to the processor’s I/O ports or the I/O
ports of a supporting system device such as memory, an
FPGA or a data converter. To ensure that the I/O loads are
not driven until the core voltage is properly biased, tracking
of the core supply and the I/O supply voltage is necessary.
Designing a system without proper power supply
sequencing for signal processing devices like DSPs, FPGAs,
and PLDs may create risks as to reliability or proper
functionality. The risk comes when there are active and
inactive power supply rails on the device for a long time.
During this time, the ESD structures, internal circuits and
components are stressed from interference between
different voltages (from the two separate power supply
rails). When these conditions persist on multi ? supply
devices for long time periods (this is a cumulative
phenomenon), the life of the products (DSP, FPGA, and
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相关代理商/技术参数 |
参数描述 |
|---|---|
| NCP3122MNTXG | 功能描述:直流/直流开关调节器 Dual 2.0 Switching Regulator RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| NCP3122QPBCKGEVB | 功能描述:电源管理IC开发工具 NCP3122 2A HF BUCK DB 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 |
| NCP3123MNTXG | 功能描述:直流/直流开关调节器 Dual 3.0 A Switching Regulator RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| NCP3123MNTXG-CUT TAPE | 制造商:ON 功能描述:NCP3123 Series 13.2 V Dual 3 A Step-Down DC/DC Switching Regulator - QFN-32 |
| NCP3123QPBCKGEVB | 功能描述:电源管理IC开发工具 NCP3123 3A HF BUCK DB 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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