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| 型号： | LMR10510YSDDEMO/NOPB |
| 厂商： | National Semiconductor |
| 文件页数： | 10/26页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR LMR10510 |
| 标准包装： | 1 |
| 系列： | SIMPLE SWITCHER® |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 1.8V |
| 电流 - 输出： | 1A |
| 输入电压： | 3 V ~ 5.5 V |
| 稳压器拓扑结构： | 降压 |
| 频率 - 开关： | 3MHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | LMR10510 |
SNVS727B – OCTOBER 2011 – REVISED APRIL 2013
Design Guide
INDUCTOR SELECTION
The Duty Cycle (D) can be approximated quickly using the ratio of output voltage (V O ) to input voltage (V IN ):
D=
V OUT
V IN
The catch diode (D1) forward voltage drop and the voltage drop across the internal PMOS must be included to
calculate a more accurate duty cycle. Calculate D by using the following formula:
D=
V OUT + V D
V IN + V D - V SW
V SW can be approximated by:
V SW = I OUT x R DSON
The diode forward drop (V D ) can range from 0.3V to 0.7V depending on the quality of the diode. The lower the
V D , the higher the operating efficiency of the converter. The inductor value determines the output ripple current.
Lower inductor values decrease the size of the inductor, but increase the output ripple current. An increase in the
inductor value will decrease the output ripple current.
One must ensure that the minimum current limit (1.2A) is not exceeded, so the peak current in the inductor must
be calculated. The peak current (I LPK ) in the inductor is calculated by:
I LPK = I OUT + Δ i L
' i L
I OUT
V IN - V OUT
L
V OUT
L
DT S
T S
t
Figure 23. Inductor Current
V IN - V OUT
L
=
2 ' i L
DT S
In general,
Δ i L = 0.1 x (I OUT ) → 0.2 x (I OUT )
If Δ i L = 20% of 1A, the peak current in the inductor will be 1.2A. The minimum specified current limit over all
operating conditions is 1.2A. One can either reduce Δ i L , or make the engineering judgment that zero margin will
be safe enough. The typical current limit is 1.75A.
The LMR10510 operates at frequencies allowing the use of ceramic output capacitors without compromising
transient response. Ceramic capacitors allow higher inductor ripple without significantly increasing output ripple.
See the OUTPUT CAPACITOR section for more details on calculating output voltage ripple. Now that the ripple
current is determined, the inductance is calculated by:
L=
DT S
2 ' i L
x (V IN - V OUT )
where
?
T S =
1
f S
10
Product Folder Links: LMR10510
Copyright ? 2011–2013, Texas Instruments Incorporated
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LMR10510YSDE/NOPB | 功能描述:直流/直流开关调节器 SIMPLE SWITCHER 5.5 Vin,1A SD Vltg Reg 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 |
| LMR10510YSDX | 制造商:TI 制造商全称:Texas Instruments 功能描述:SIMPLE SWITCHER?? 5.5Vin, 1A Step-Down Voltage Regulator in SOT-23 and LLP |
| LMR10510YSDX/NOPB | 功能描述:直流/直流开关调节器 SIMPLE SWITCHER 5.5 Vin,1A SD Vltg Reg 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 |
| LMR10515 | 制造商:TI 制造商全称:Texas Instruments 功能描述:SIMPLE SWITCHER? 5.5Vin, 1.5A Step-Down Voltage Regulator in SOT-23 and LLP |
| LMR10515XMF | 制造商:Texas Instruments 功能描述:BUCK, 1.5A, 5.5VIN 制造商:Texas Instruments 功能描述:BUCK, 1.5A, 5.5VIN; Primary Input Voltage:5.5V; No. of Outputs:1; Output Voltage:4.5V; Output Current:1.5A; Voltage Regulator Case Style:SOT-23; No. of Pins:5; Operating Temperature Min:-40C; Operating Temperature Max:125C; SVHC:No;RoHS Compliant: Yes |
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