参数资料
型号: R1224N222M-TR
英文描述: SMPS Controller
中文描述: 开关电源控制器
文件页数: 9/36页
文件大小: 503K
代理商: R1224N222M-TR
12345
Rev. 1.12 - 9 -
V
IN
=V
OUT
+(Rp+R
L
)
×
I
OUT
+L
×
I
RP
/ton
Equation 3
When Lx Tr. is OFF:
L
×
I
RP
/toff = V
F
+V
OUT
+R
L
×
I
OUT
Equation 4
Put Equation 4 to Equation 3 and solve for ON duty, ton/(toff+ton)=D
ON
,
D
ON
=(V
OUT+
V
F
+R
L
×
I
OUT
)/(V
IN
+V
F
-Rp
×
I
OUT
)
Equation 5
Ripple Current is as follows;
I
RP
=(V
IN
-V
OUT
-Rp
×
I
OUT
-R
L
×
I
OUT
)
×
D
ON
/f/L
Equation 6
Wherein, peak current that flows through L, Lx Tr., and SD is as follows;
ILmax=I
OUT
+I
RP
/2
Equation 7
Consider ILmax, condition of input and output and select external components.
#
The above explanation is directed to the calculation in an ideal case in continuous mode.
I
External Components
1. Inductor
Select an inductor that peak
current does not exceed ILmax. If larger current than allowable current flows,
magnetic saturation occurs and make transform efficiency worse.
When the load current is definite, the smaller value of L, the larger the ripple current.
Provided that the allowable current is large in that case and DC current is small, therefore, for large output current,
efficiency is better than using an inductor with a large value of L and vice versa.
2. Diode
Use a diode with low V
F
(Schottky type is recommended.) and high switching speed.
Reverse voltage rating should be more than V
IN
and current rating should be equal or more than ILmax.
3. Capacitors
As for C
IN
, use a capacitor with low ESR (Equivalent Series Resistance) and a capacity of at least 10
μ
F for stable
operation.
C
OUT
can reduce ripple of Output Voltage, therefore 47
μ
F or more value of tantalum type capacitor is
recommended.
4. Lx Transistor
Pch Power MOSFET is required for this IC.
Its breakdown voltage between gate and source should be a few V higher than Input Voltage.
In the case of Input Voltage is low, to turn on MOSFET completely, to use a MOSFET with low threshold voltage is
effective.
If a large load current is necessary for your application and important, choose a MOSFET with low ON resistance
for good efficiency.
If a small load current is mainly necessary for your application, choose a MOSFET with low gate capacity for good
efficiency.
Maximum continuous drain current of MOSFET should be larger than peak current, ILmax.
相关PDF资料
PDF描述
R1224N232E-TR SMPS Controller
R1224N232F-TR SMPS Controller
R1224N262E-TR SMPS Controller
R1224N262F-TR Analog IC
R1224N262G-TR SMPS Controller
相关代理商/技术参数
参数描述
R122BA19.38.62 功能描述:12 AWG 2C 19/25 BC .009" PVC RoHS:是 类别:线缆,导线 >> 多芯导线 系列:* 标准包装:1 系列:*
R122BA19.40.62 功能描述:12 AWG 2C 19/25 BC .009" PVC RoHS:是 类别:线缆,导线 >> 多芯导线 系列:* 标准包装:1 系列:*
R122BA19.41.01 功能描述:2C/12 19/.0185BC UNSH CL3R RoHS:是 类别:线缆,导线 >> 多芯导线 系列:* 标准包装:1 系列:*
R122BA19.41.06 功能描述:12 AWG 2C 19/25 BC .009" PVC RoHS:是 类别:线缆,导线 >> 多芯导线 系列:* 标准包装:1 系列:*
R122BA19.41.62 功能描述:2C/12 19/.0185BC UNSH CL3R RoHS:是 类别:线缆,导线 >> 多芯导线 系列:* 标准包装:1 系列:*