参数资料
| 型号： | MIC26600YJL TR |
| 厂商： | Micrel Inc |
| 文件页数： | 14/28页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 7A 28-MLF |
| 产品培训模块： | SuperSwitcherII™ - Step Down DC-DC Regulator Family |
| 标准包装： | 1 |
| 系列： | Hyper Speed Control™，SuperSwitcher II™ |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 可调至 0.8V |
| 输入电压： | 4.5 V ~ 26 V |
| PWM 型： | 混合物 |
| 频率 - 开关： | 300kHz |
| 电流 - 输出： | 7A |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-VQFN 裸露焊盘，28-MLF? |
| 包装： | 标准包装 |
| 供应商设备封装： | 28-MLF?（5x6） |
| 其它名称： | 576-3716-6 |
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Micrel, Inc.
Functional Description
The MIC26600 is an adaptive ON-time synchronous
step-down DC-DC regulator. It is designed to operate
over a wide input voltage range from, 4.5V to 26V, and
provides a regulated output voltage at up to 7A of output
current. A digitally modified adaptive ON-time control
scheme is employed in to obtain a constant switching
frequency and to simplify the control compensation.
Over-current protection is implemented without the use
of an external sense resistor. The device includes an
internal soft-start function which reduces the power
supply input surge current at start-up by controlling the
output voltage rise time.
Theory of Operation
Figure 1 illustrates the block diagram for the control loop
of the MIC26600. The output voltage is sensed by the
MIC26600 feedback pin FB via the voltage divider R1
and R2, and compared to a 0.8V reference voltage V REF
at the error comparator through a low gain
transconductance (g m ) amplifier. If the feedback voltage
decreases and the output of the g m amplifier is below
0.8V, then the error comparator will trigger the control
logic and generate an ON-time period. The ON-time
period length is predetermined by the “FIXED t ON
ESTIMATION” circuitry:
MIC26600
It is not recommended to use MIC26600 with a OFF-time
close to t OFF(min) during steady-state operation. Also, as
V OUT increases, the internal ripple injection will increase
and reduce the line regulation performance. Therefore,
the maximum output voltage of the MIC26600 should be
limited to 5.5V. Please refer to “Setting Output Voltage”
subsection in “Application Information” for more details.
The actual ON-time and resulting switching frequency
will vary with the part-to-part variation in the rise and fall
times of the internal MOSFETs, the output load current,
and variations in the V DD voltage. Also, the minimum t ON
results in a lower switching frequency in high V IN to V OUT
applications, such as 26V to 1.0V. The minimum t ON
measured on the MIC26600 evaluation board is about
184ns. During load transients, the switching frequency is
changed due to the varying OFF-time.
To illustrate the control loop operation, will be analyzed
both the steady-state and load transient scenarios. For
easy analysis, the gain of the g m amplifier is assumed to
be 1. With this assumption, the inverting input of the
error comparator is the same as the feedback voltage.
Figure 2 shows the MIC26600 control loop timing during
steady-state operation. During steady-state, the g m
amplifier senses the feedback voltage ripple, which is
proportional to the output voltage ripple and the inductor
current ripple, to trigger the ON-time period. The ON-
t ON(estimat ed) =
V OUT
V IN × 300kHz
(1)
time is predetermined by the t ON estimator. The
termination of the OFF-time is controlled by the feedback
voltage. At the valley of the feedback voltage ripple,
which occurs when V FB falls below V REF , the OFF period
ends and the next ON-time period is triggered through
where V OUT is the output voltage and V IN is the power
stage input voltage.
At the end of the ON-time period, the internal high-side
driver turns off the high-side MOSFET and the low-side
driver turns on the low-side MOSFET. The OFF-time
period length depends upon the feedback voltage in
most cases. When the feedback voltage decreases and
the output of the g m amplifier is below 0.8V, the ON-time
period is triggered and the OFF-time period ends. If the
OFF-time period determined by the feedback voltage is
less than the minimum OFF-time t OFF(min) , which is about
360ns, the MIC26600 control logic will apply the t OFF(min)
instead. t OFF(min) is required to maintain enough energy in
the boost capacitor (C BST ) to drive the high-side
MOSFET. The maximum duty cycle is obtained from the
360ns t OFF(min) :
the control logic circuitry.
D max =
t S ? t OFF(min)
t S
= 1 ?
360ns
t S
(2)
Figure 2. MIC26600 Control Loop Timing
where t S = 1/300kHz = 3.33 μ s.
July 2011
14
M9999-070111-C
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相关代理商/技术参数 |
参数描述 |
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| MIC26601YJL EV | 功能描述:电源管理IC开发工具 28V/6A DC-DC Buck Regulator w/ HSC - Evaluation Board 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 |
| MIC26601YJL TR | 功能描述:直流/直流开关调节器 28V/6A DC-DC Buck Regulator w/ HSC RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MIC26601YJLEV | 制造商:Micrel Inc 功能描述:Evaluation Board for MIC26601YJL |
| MIC26601YJL-EV | 功能描述:MIC26601 Hyper Speed Control?, SuperSwitcher II? DC/DC, Step Down 1, Non-Isolated Outputs Evaluation Board 制造商:microchip technology 系列:Hyper Speed Control?，SuperSwitcher II? 零件状态:无货 主要用途:DC/DC，步降 输出和类型:1，非隔离 功率 - 输出:- 电压 - 输出:5V 电流 - 输出:6A 电压 - 输入:5.5 V ~ 28 V 稳压器拓扑:降压 频率 - 开关:600kHz 板类型:完全填充 所含物品:板 使用的 IC/零件:MIC26601 标准包装:1 |
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