参数资料
型号: EL7512CYZ
厂商: Intersil
文件页数: 6/8页
文件大小: 0K
描述: IC REG CTRLR BST PWM 10-MSOP
标准包装: 50
PWM 型: 控制器
输出数: 1
频率 - 最大: 1.2MHz
占空比: 90%
电源电压: 2 V ~ 12 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: -40°C ~ 85°C
封装/外壳: 10-TFSOP,10-MSOP(0.118",3.00mm 宽)
包装: 管件
EL7512
? I L = --------- × -------
F S
V O – V IN
Applications Information
The EL7512 is a step-up regulator, operated at fixed
frequency pulse-width-modulation (PWM) control. The input
voltage is 2V-12V and output voltage is 5V-18V. The
switching frequency (up to 1.2MHz) is decided by the
resistor connected to RT pin.
Start-Up
After V DD reaches a threshold of about 2V, the start-up
oscillator generates fixed duty-ratio of 0.5-0.7 at a frequency
of several hundred kilohertz. This will boost the output
voltage.
When V DD reaches about 3.7V, the PWM comparator takes
over the control. The duty ratio will be decided by the
multiple-input direct summing comparator, Max_Duty signal
where:
? I L is the inductor peak-to-peak current ripple and is
decided by:
V IN D
L
D is the MOSFET turn-on ratio and is decided by:
D = ------------------------
V O
F S is the switching frequency.
The following table gives typical values:
MAX CONTINUOUS OUTPUT CURRENTS
I OMAX
(about 90% duty-ratio), and the Current Limit Comparator,
whichever is the smallest.
The soft-start is provided by the current limit comparator. As
the internal 12μA current source charges the external CSS,
the peak MOSFET current is limited by the voltage on the
capacitor. This in turn controls the rising rate of the output
voltage.
The regulator goes through the start-up sequence as well
after the EN signal is pulled to HI.
Steady-State Operation
When the output reaches the preset voltage, the regulator
operates at steady state. Depending on the input/output
conditions and component values, the inductor operates at
either continuous-conduction mode or discontinuous-
conduction mode.
In the continuous-conduction mode, the inductor current is a
V IN (V)
2
2
2
3.3
3.3
3.3
5
5
5
9
9
12
12
V O (V)
5
9
12
5
9
12
9
12
15
12
15
15
18
L (μH)
10
10
10
10
10
10
10
10
10
10
10
10
11
F S (kHz)
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
(mA)
360
190
140
600
310
230
470
340
260
630
470
670
510
triangular waveform and LX voltage a pulse waveform. In the
I LAVG = -------------
I LPK = I LAVG + -------- L
V IN
I OMAX = ? 1 – -------- L ? × ---------
V O
discontinuous-conduction mode, the inductor current is
completely dried out before the MOSFET is turned on again.
The input voltage source, the inductor, and the MOSFET and
output diode parasitic capacitors forms a resonant circuit.
Oscillation will occur in this period. This oscillation is normal
and will not affect the regulation.
At very low load, the MOSFET will skip pulses sometimes.
This is normal.
Current Limit
The MOSFET current limit is nominally 1.2A and guaranteed
1A. This restricts the maximum output current I OMAX based
on the following formula:
? I
? 2 ?
Component Considerations
It is recommended that C IN is larger than 10μF.
Theoretically, the input capacitor has ripple current of ? I L .
Due to high-frequency noise in the circuit, the input current
ripple may exceed the theoretical value. Larger capacitor will
reduce the ripple further.
The inductor has peak and average current decided by:
I O
1 – D
? I
2
The inductor should be chosen to be able to handle this
current. Furthermore, due to the fixed internal
compensation, it is recommended that maximum inductance
of 10μH and 15μH to be used in the 5V and 12V or higher
output voltage, respectively.
The output diode has average current of I O , and peak
current the same as the inductor's peak current. Schottky
6
相关PDF资料
PDF描述
X5169PIZ-2.7 IC SUPERVISOR CPU 16K EE 8-DIP
X5169PIZ IC SUPERVISOR CPU 16K EE 8-DIP
X5165S8Z-2.7 IC CPU SUPERV 16K EEPROM 8-SOIC
X5165S8Z-2.7A IC CPU SUPERV 16K EEPROM 8-SOIC
X5165S8Z-4.5A IC CPU SUPERV 16K EEPROM 8-SOIC
相关代理商/技术参数
参数描述
EL7512CYZ-T13 功能描述:IC REG CTRLR BST PWM 10-MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:40-VFQFN 裸露焊盘 包装:带卷 (TR)
EL7512CYZ-T7 功能描述:IC REG CTRLR BST PWM 10-MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:40-VFQFN 裸露焊盘 包装:带卷 (TR)
EL7513 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:White LED Step-Up Regulator
EL7513_06 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:White LED Step-Up Regulator
EL7513AIWTZ-T7 制造商:Rochester Electronics LLC 功能描述:- Bulk