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参数资料
| 型号： | MIC2601YML TR |
| 厂商： | Micrel Inc |
| 文件页数： | 9/13页 |
| 文件大小： | 0K |
| 描述： | IC REG BOOST ADJ 1.2A 8MLF |
| 特色产品： | 40V Wide Input Range Boost Regulator |
| 标准包装： | 1 |
| 类型： | 升压（升压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 可调至 40V |
| 输入电压： | 4.5 V ~ 20 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 1.12MHz |
| 电流 - 输出： | 1.2A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-VFDFN 裸露焊盘，8-MLF? |
| 包装： | 标准包装 |
| 供应商设备封装： | 8-MLF?（2x2） |
| 产品目录页面： | 1093 (CN2011-ZH PDF) |
| 其它名称： | 576-3283-6 |
Micrel, Inc.
Application Information
DC-to-DC PWM Boost Conversion
The MIC2601/2 is a constant frequency boost converter.
It operates by taking a DC input voltage and regulating a
higher DC output voltage. Figure 2 shows a typical
circuit. Boost regulation is achieved by turning on an
internal switch, which draws current through the inductor
(L1). When the switch turns off, the inductor’s magnetic
field collapses, causing the current to be discharged into
the output capacitor through an external Schottky diode
(D1). Voltage regulation is achieved through pulse-width
modulation (PWM).
10μH
V IN V OUT
MIC2601/2
Component Selection
Inductor
Inductor selection is a balance between efficiency,
stability, cost, size, and rated current. For most
applications, a 10μH is the recommended inductor
value; it is usually a good balance between these
considerations. Large inductance values reduce the
peak-to-peak ripple current, affecting efficiency. This has
an effect of reducing both the DC losses and the
transition losses. There is also a secondary effect of an
inductor’s DC resistance (DCR). The DCR of an inductor
will be higher for more inductance in the same package
size. This is due to the longer windings required for an
increase in inductance. Since the majority of input
current (minus the MIC2601 operating current) is passed
MIC2601/2
VIN SW
6.65K
through the inductor, higher DCR inductors will reduce
efficiency. To maintain stability, increasing inductor size
will have to be met with an increase in output
2.2μF
GND
0.1μF
EN FB
VDD SS
AGND PGND
0.1μF
10μF
GND
capacitance. This is due to the unavoidable “right half
plane zero” effect for the continuous current boost
converter topology. The frequency at which the right half
plane zero occurs can be calculated as follows:
( D ) 2 ? V O
FRHPZ =
2 ? π ? L ? I O
Figure 2. Typical Application Circuit
Duty Cycle Considerations
Duty cycle refers to the switch on-to-off time ratio and
can be calculated as follows for a boost regulator:
The right half plane zero has the undesirable effect of
increasing gain, while decreasing phase. This requires
that the loop gain is rolled off before this has significant
effect on the total loop response. This can be
accomplished by either reducing inductance (increasing
D = 1 ?
V IN
V OUT
RHPZ frequency) or increasing the output capacitor
value (decreasing loop gain).
The duty cycle required for voltage conversion should be
less than the maximum duty cycle of 85%. Also, in light
load conditions, where the input voltage is close to the
output voltage, the minimum duty cycle can cause pulse
skipping. This is due to the energy stored in the inductor
causing the output to overshoot slightly over the
regulated output voltage. During the next cycle, the error
amplifier detects the output as being high and skips the
following pulse. This effect can be reduced by increasing
the minimum load or by increasing the inductor value.
Increasing the inductor value reduces peak current,
which in turn reduces energy transfer in each cycle.
Overvoltage Protection
For the MIC2601/2 there is an over voltage protection
function. If the output voltage overshoots the set voltage
by 15% when feedback is high during input higher than
output, turn on, load transients, line transients, load
disconnection etc. the MIC2601/2 OVP ckt will shut the
switch off saving itself and other sensitive circuitry
downstream.
Output Capacitor
Output capacitor selection is also a trade-off between
performance, size, and cost. Increasing output
capacitance will lead to an improved transient response,
but also an increase in size and cost. X5R or X7R
dielectric ceramic capacitors are recommended for
designs with the MIC2601/2. Y5V values may be used,
but to offset their tolerance over temperature, more
capacitance is required.
Diode Selection
The MIC2601/2 requires an external diode for operation.
A Schottky diode is recommended for most applications
due to their lower forward voltage drop and reverse
recovery time. Ensure the diode selected can deliver the
peak inductor current and the maximum reverse voltage
is rated greater than the output voltage.
Input capacitor
A minimum 2.2 μ F ceramic capacitor is recommended for
designing with the MIC2601/2. Increasing input
capacitance will improve performance and greater noise
September 2009
9
M9999-090909-A
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相关代理商/技术参数 |
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|---|---|
| MIC2602YML | 制造商:Micrel 功能描述:0.2A, 2MHz Wide Input Boost Regulator |
| MIC2602YML TR | 功能描述:直流/直流开关调节器 1.2A 2 MHz Wide Input Range Boost Regulator 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 |
| MIC2602YML-TR | 功能描述:Boost Switching Regulator IC Positive Adjustable 4.5V 1 Output 1.2A (Switch) 8-VFDFN Exposed Pad, 8-MLF? 制造商:microchip technology 系列:- 包装:剪切带（CT） 零件状态:停产 功能:升压 输出配置:正 拓扑:升压 输出类型:可调式 输出数:1 电压 - 输入（最小值）:4.5V 电压 - 输入（最大值）:20V 电压 - 输出（最小值/固定）:4.5V 电压 - 输出（最大值）:40V（开关） 电流 - 输出:1.2A（开关） 频率 - 开关:1.92MHz 同步整流器:无 工作温度:-40°C ~ 125°C （TJ） 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘，8-MLF? 供应商器件封装:8-MLF?（2x2） 标准包装:1 |
| MIC2605YML | 制造商:Micrel 功能描述:0.5A 1.2MHz Wide In Boost Reg w Schottky |
| MIC2605YML TR | 功能描述:直流/直流开关调节器 0.5A 1.2 MHz Wide Input Range Boost Regulator w/ Integrated Schottky 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 |
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