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| 型号： | MAX5066EUI+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 13/22页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 28TSSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 50 |
| PWM 型： | 电流模式 |
| 输出数： | 2 |
| 频率 - 最大： | 1MHz |
| 电源电压： | 4.75 V ~ 28 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： | 28-SOIC（0.173"，4.40mm 宽）裸露焊盘 |
| 包装： | 管件 |
Configurable, Single-/Dual-Output, Synchronous
Buck Controller for High-Current Applications
oscillator. The PWM on-cycle terminates when the ramp
voltage exceeds the error voltage from the current-error
amplifier (CEA1).
The outer voltage control loop consists of the voltage-
error amplifier (VEA1). The noninverting input (EAN1) is
externally connected to the midpoint of a resistive volt-
age-divider from OUT1 to EAN1 to AGND. The voltage
loop gain is set by using an external resistor from the
output of this amplifier (EAOUT1) to its inverting input
Voltage Error Amplifier
The voltage-error amplifier (VEA_) sets the gain of the
voltage control loop. Its output clamps to 1.14V and
-0.234V relative to V CM = 0.61V. Set the MAX5066 out-
put voltage by connecting a voltage-divider from the
output to EAN_ to GND (see Figure 4 ). At no load the
output of the voltage error amplifier is zero.
Use the equation below to calculate the no load voltage:
V OUT ( NL ) = 0 . 6135 × ? 1 +
(EAN1). The noninverting input of (VEA1) is connected
to the 0.61V internal reference.
Peak-Current Comparator
The peak-current comparator (see Figure 3 ) monitors
?
?
The voltage at full load is given by:
R 1 ?
R 2 ? ?
V OUT ( FL ) = 0 . 6135 × ? 1 +
the voltage across the current-sense resistor (R SENSE )
and provides a fast cycle-by-cycle current limit with a
threshold of 52.5mV. Note that the average current-limit
threshold of 22.5mV still limits the output current during
?
?
R 1 ?
R 2 ? ?
? ? V OUT
R F = OUT SENSE
short-circuit conditions. To prevent inductor saturation,
select an output inductor with a saturation current
specification greater than the average current limit of
22.5mV/R SENSE . Proper inductor selection ensures that
only extreme conditions trip the peak-current compara-
tor, such as a damaged output inductor. The typical
propagation delay of the peak current-limit comparator
is 260ns.
Current-Error Amplifier
The MAX5066 has two dedicated transconductance
current-error amplifiers CEA1 and CEA2 with a typical
g M of 550μS and 320μA output sink and source capabil-
ity. The current-error amplifier outputs (CLP1 and CLP2)
serve as the inverting input to the PWM comparators.
CLP1 and CLP2 are externally accessible to provide fre-
quency compensation for the inner current loops (see
C CFF , C CF , and R CF in Figure 2). Compensate the cur-
rent-error amplifier such that the inductor current down
slope, which becomes the up slope at the inverting
input of the PWM comparator, is less than the slope of
the internally generated voltage ramp (see the
Compensation section).
PWM Comparator and R-S Flip-Flop
The PWM comparator (CPWM1 or CPWM2) sets the
duty cycle for each cycle by comparing the current-
error amplifier output to a 2V P-P ramp. At the start of
each clock cycle an R-S flip-flop resets and the high-
side drivers (DH1 and DH2) turn on. The comparator
sets the flip-flop as soon as the ramp voltage exceeds
the current-error amplifier output voltage, thus terminat-
ing the on cycle.
where ? V OUT is the voltage-positioning window
described in the Adaptive Voltage Positioning section.
Adaptive Voltage Positioning
Powering new-generation ICs requires new techniques
to reduce cost, size, and power dissipation. Voltage
positioning ( Figure 5 ) reduces the total number of out-
put capacitors to meet a given transient response
requirement. Setting the no-load output voltage slightly
higher than the output voltage during nominally loaded
conditions allows a larger downward voltage excursion
when the output current suddenly increases.
Regulating at a lower output voltage under a heavy
load allows a larger upward-voltage excursion when
the output current suddenly decreases. A larger
allowed voltage-step excursion reduces the required
number of output capacitors and/or allows the use of
higher ESR capacitors.
The internal 0.61V reference in the MAX5066 has a toler-
ance of ±0.9%. If we use 0.1% resistors for R 1 and R 2 ,
we still have another 4% available for the variation in the
output voltage from nominal. This available voltage
range allows us to reduce the total number of output
capacitors to meet a given transient response require-
ment. This results in a voltage-positioning window as
shown in Figure 5.
From the allowable voltage-positioning window we can
calculate the value of R F from the equation below.
I × R × 36 × R 1
? V OUT
where ? V OUT is the allowable voltage-positioning win-
dow, R SENSE is the sense resistor, 36 is the current-
sense amplifier gain, and R 1 is as shown in Figure 4.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX5066EUI+ | 功能描述:DC/DC 开关控制器 Synch Buck Controller 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 |
| MAX5066EUI+T | 功能描述:DC/DC 开关控制器 Synch Buck Controller 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 |
| MAX5066EUI-T | 功能描述:DC/DC 开关控制器 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 |
| MAX5066EVKIT | 功能描述:电源管理IC开发工具 MAX5066 Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| MAX5067 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Dual-Phase, +0.6V to +3.3V Output Parallelable, Average-Current-Mode Controllers |
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