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参数资料
| 型号： | SP7661EB |
| 厂商： | Exar Corporation |
| 文件页数： | 12/20页 |
| 文件大小： | 0K |
| 描述： | EVAL BOARD FOR SP7661 |
| 标准包装： | 1 |
| 系列： | * |
APPLICATIONS INFORMATION
capacitor ESR and capacitance. Ignoring
the inductor ripple current, the input voltage
ripple can be determined by:
?V IN =
I OUT(MAX) ? R ESR(CIN) + I OUT(MAX) ?V OUT ?(V IN - V OUT )
V 2 IN ? ? s ? C IN
The capacitor type suitable for the output
capacitors can also be used for the input
capacitors. However, exercise extra caution
when tantalum capacitors are used. Tantalum
capacitors are known for catastrophic failure
when exposed to surge current, and input
capacitors are prone to such surge current
when power supplies are connected “live”
to low impedance power sources. Although
tantalum capacitors have been successfully
employed at the input, it is generally not
recommended.
Loop Compensation Design
The open loop gain of the whole system can
be divided into the gain of the error ampli -
fier, PWM modulator, buck converter output
stage, and feedback resistor divider. In order
to cross over at the desired frequency cut-off
(FCO), the gain of the error amplifier must
compensate for the attenuation caused by
the rest of the loop at this frequency. The
goal of loop compensation is to manipu -
late loop frequency response such that its
crossover gain at 0db, results in a slope of
-20db/decade.
The first step of compensation design is
to pick the loop crossover frequency. High
crossover frequency is desirable for fast
transient response, but often jeopardizes the
power supply stability. Crossover frequency
should be higher than the ESR zero but
less than 1/5 of the switching frequency or
Type III Voltage Loop
Compensation
G AMP (s) Gain Block
PWM Stage
G PWM Gain
Block
Output Stage
G OUT (s) Gain
Block
V REF
(Volts)
(SRz2Cz2+1)(SR1Cz3+1)
SR1Cz2(SRz3Cz3+1)(SRz2Cp1+1)
V IN
V RAMP_PP
(SR ESR C OUT + 1)
[S^2LC OUT +S(R ESR +R DC ) C OUT +1]
V OUT
(Volts)
Notes:
R ESR = Output Capacitor Equivalent Series Resistance.
R DC = Output Inductor DC Resistance.
V RAMP_PP = SP7662 Internal Ramp Amplitude Peak-to-Peak Voltage.
Condition:
Cz2 >> Cp1 & R1 >> Rz3
Output Load Resistance >> R ESR & R DC
Voltage Feedback
G FBK Gain Block
V FBK
(Volts)
R 2
(R 1 + R 2 )
or
V REF
V OUT
SP7661 Voltage Mode Control Loop with Loop Dynamic
Mar -07 Rev N
SP766 Wide Input Voltage Range 3A, 600kHz Buck Regulator
2
? 2007 Sipex Corporation
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP7661ER | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Evaluation Board Manual |
| SP7661ER/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range 3A, 600kHz, Buck Regulator |
| SP7661ER-L | 功能描述:开关变换器、稳压器与控制器 Buck Regulator RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
| SP7661ERL/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range 3A, 600kHz, Buck Regulator |
| SP7661ER-L/TR | 功能描述:开关变换器、稳压器与控制器 WIDE INPUT VOLTAGE Range A600KHz RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
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