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参数资料
| 型号： | MIC9130YQS TR |
| 厂商： | Micrel Inc |
| 文件页数： | 15/19页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR DC-DC PWM HV HS 16-QSOP |
| 标准包装： | 2,500 |
| 应用： | 控制器，电信 |
| 输入电压： | 9 V ~ 18 V |
| 输出数： | 1 |
| 输出电压： | 4.7 V ~ 5 V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-SSOP（0.154"，3.90mm 宽） |
| 供应商设备封装： | 16-QSOP |
| 包装： | 带卷 (TR) |
| 其它名称： | MIC9130YQSTR MIC9130YQSTR-ND |
MIC9130
series resistance is 10K, for a 500kHz switcher, the maximum
series resistance is 2K.
Sensing Current with a Resistor
The fast transition times of the current signal prohibit the use
of inductive resistors. Standard wire wound power resistors
will not work. Carbon composition or metal ? lm resistors or
low inductance power resistors may be used. The overcurrent
range of the power supply and component tolerances must be
considered when selecting the current sense resistor value.
The power supply speci ? cation may call for an overcurrent
limit, which must be accounted for when selecting the cur-
rent sense resistor value. The relationship between the peak
primary current and the current sense resistor is:
Micrel, Inc.
Sensing Current with a Current Sense Transformer
At higher power levels, the power dissipation in a current sense
resistor is excessive. A current sense transformer can be
used to sense the current while minimizing power dissipation.
See Figure 11. The schematic shows the circuitry necessary
when using a current sense transformer. The resistor, R1,
provides a path to reset the current sense transformer. The
resistor, R2, converts the scaled down current to a voltage,
which is sent to the ISNS pin.
V IN
V ISNS = I P × R ISENSE + I ISNS × R f
where: Ip is the current in the sense resistor
R ISENSE is the current sense resistance
I SNS
(pin 14)
MIC9130
Rf
R2
R1
Current Sense
Transformer
I PRI
V SENSE 0.5
I SENSE
R SENSE = = = 0.5 Ω
V ISNS = × R 2 + I ISNS × R f
I ISNS is the current sourced from the ISNS pin
(40 μ A)
R f is the series resistor between the ISNS pin and
the current sense resistor.
The current sense resistor must not be too small or the cur-
rent sense signal will be susceptible to noise. If noise is a
problem, the current signal level should be increased.
An example is illustrated below.
The maximum peak current, I PMAX = 1A at 120% overcurrent
and minimum input voltage
The maximum rms current, I RMS =0.65A
The desired current sense signal amplitude is 500mV at 1A
output current.
The current sense resistor value and power dissipation is:
1
P DISS = I RMS 2 × R SENSE = 0 . 65 2 × 0 . 5 = 0 . 21 W
A 0.5 Ω , non inductive resistor with at least a 1/2W rating
should be selected.
The series resistor is calculated to allow the 500mV-peak
signal to reach 0.82V.
OUT
(pin 16)
Figure 11
The voltage at the ISNS pin is calculated by:
I P
N
where: I P is the current in the primary of the current sense
transformer
R2 is the current sense resistance at the
secondary of the current sense transformer
N is the turns ratio of the current sense
transformer (N=Nsec/Npri)
I ISNS is the current sourced from the ISNS pin
(40 μ A)
R f is the series resistor between the ISNS pin and
the current sense resistor.
Current Transformer example:
The maximum peak current, I PMAX = 5A at 120% overcur-
rent and minimum input voltage
V ISNS ? ( I P × R ISENSE ) 0 . 82 ? ( 1 × 0 . 5 )
I ISNS
R f =
40μA
The next lower value of 10k Ω is selected.
= 10 . 25 k Ω
The maximum rms current, I RMS = 3.25A
The full 0.82V peak signal a the ISNS input can be used
since very little power is dissipation in the secondary
side sense resistor. The maximum peak to peak volt-
The bandwidth of the 10K resistor and the 25pF input capaci-
tance is calculated. The resistor value must be lowered if the
bandwidth is too low for the switching frequency.
age at the sense pin (pin 14) is 0.82V at the 5A maximum
output current.
The current sense resistor value and power dissipation
BW =
= 630 kHz
R 2 = SENSE
1
2 × π × 10 k × 25 pF
The maximum switching frequency of this power supply
is:
V
I P
× N
=
0. 82 × 100
5
= 16 . 4 Ω
?
? I
? 3 . 25 ?
P DISS = ? PRMS ? × R 2 = ? ? × 16 . 4 = 17 . 4 mW
should be approximately six times less than the BW to pre-
vent current waveform distortion and excessive delays in
the current loop. This limits the switching frequency to the
range of 100kHz.
2 2
? N ? ? 100 ?
November 2008
15
M9999-111108
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相关代理商/技术参数 |
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|---|---|
| MIC9131 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:High-Voltage, High-Speed Telecom |
| MIC9131_06 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:High-Voltage, High-Speed Telecom |
| MIC9131BM | 功能描述:IC CTRLR DC-DC PWM HV HS 16-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,000 系列:- 应用:电源，ICERA E400，E450 输入电压:4.1 V ~ 5.5 V 输出数:10 输出电压:可编程 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:42-WFBGA，WLCSP 供应商设备封装:42-WLP 包装:带卷 (TR) |
| MIC9131BM TR | 功能描述:IC CTRLR DC-DC PWM HV HS 16-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,000 系列:- 应用:电源，ICERA E400，E450 输入电压:4.1 V ~ 5.5 V 输出数:10 输出电压:可编程 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:42-WFBGA，WLCSP 供应商设备封装:42-WLP 包装:带卷 (TR) |
| MIC9131BQS | 功能描述:IC CTRLR DC-DC PWM HV HS 16-QSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,000 系列:- 应用:电源，ICERA E400，E450 输入电压:4.1 V ~ 5.5 V 输出数:10 输出电压:可编程 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:42-WFBGA，WLCSP 供应商设备封装:42-WLP 包装:带卷 (TR) |
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