参数资料
| 型号： | SP6120EY-L |
| 厂商： | Exar Corporation |
| 文件页数： | 18/22页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 16TSSOP |
| 标准包装： | 95 |
| 系列： | AnyFET™ |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 550kHz |
| 占空比： | 95% |
| 电源电压： | 3 V ~ 5.5 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 16-TSSOP（0.173"，4.40mm 宽） |
| 包装： | 管件 |
APPLICATIONS INFORMATION: Continued
In Figure 18, R1 and C1 provides a zero f Z1
which needs to be placed at or below f P(LC) . If f Z1
is made equal to f P(LC) for convenience, the
value of C1 can be calculated as
Current Sense
The SP6120 allows sensing current using the
inductor, PCB trace or current-sense resistor.
Inductor-sense utilizes the voltage drop across
C 1 =
1
2 π f P(LC) R 1
the ESR of the inductor, while PCB trace and
current-sense resistor introduce additional re-
sistance in series with the inductor. The resis-
C 2 =
P SEN = I OUT ( max) R SEN
The optional C2 generates a pole f P1 with R1 to
cut down high frequency noise for reliable op-
eration. This pole should be placed one decade
higher than the crossover frequency to avoid
erosion of phase margin. Therefore, the value of
the C2 can be derived from
1
20 π f CO R 1
Figure 19 illustrates the overall loop frequency
response and frequency of each pole and zero.
To fine-tune the compensation, it is necessary to
physically measure the frequency response us-
ing a network analyzer.
Gain
-20db/dec
tance of the sense element determines the
overcurrent protection threshold as follows,
I LIM = 43mV
R SEN
R SEN = current-sense resistance which can be
implemented as ESR of the inductor, trace or
discrete resistor.
The maximum power dissipation on the current-
sense element is:
2
For the inductor-sense scheme shown in the
application circuit, R S and C S are used to repli-
cate the signal across the ESR of the inductor. R S
and C S can be looked at as a low pass filter
whose output represents the DC differential
voltage between the switch node and the output.
At steady state, this voltage happens to be the
output current times the ESR of the inductor. In
addition, if the following relationship is satisfied,
-40db/dec
L
ESR
= R S C S
Loop
-20db/dec
f
the output of the RsCs filter represents the exact
voltage across the ESR, including the ripple.
Since the SP6120’s hiccup overcurrent protec-
tion scheme is intended to safeguard sustained
-20db/dec
overload conditions, the DC portion of the cur-
rent signal is more of interest. Therefore, design-
ing the R S C S time constant higher than L/ESR
provides reliable current sense against any pre-
Error Amplifier
-20db/dec
f
mature triggering due to noise or any transient
conditions. Pick Rs between 10k and 100k, and
Cs can be determined by:
f Z1 f P(LC)
f Z(ESR)
f CO
f P1
C S = 2
L 1
ESR R S
Here the time constant of R S C S is twice the value
Figure 19. Frequency response of a stable system and its
error amplifier.
of L/ESR.
Date: 1/21/05
SP6120 Low Voltage, AnyFET TM , Synchronous, Buck Controller
18
? Copyright 2005 Sipex Corporation
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP6120EY-L/TR | 功能描述:DC/DC 开关控制器 Low Voltage, AnyFET Synchronous, Cntrllr RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| SP6120HV | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:High Voltage, Synchronous ,Buck Controller Ideal for 2A to 20A, High Performance, DC-DC Power Converters |
| SP6120HVCY | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:High Voltage, Synchronous ,Buck Controller Ideal for 2A to 20A, High Performance, DC-DC Power Converters |
| SP6120HVCY/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:High Voltage, Synchronous ,Buck Controller Ideal for 2A to 20A, High Performance, DC-DC Power Converters |
| SP6120HVEY | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:High Voltage, Synchronous ,Buck Controller Ideal for 2A to 20A, High Performance, DC-DC Power Converters |
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