- 您现在的位置：买卖IC网 > PDF目录176104 > ISL6741IBZ (INTERSIL CORP) Flexible Double Ended Voltage and Current Mode PWM Controllers PDF资料下载
参数资料
| 型号： | ISL6741IBZ |
| 厂商： | INTERSIL CORP |
| 元件分类： | 稳压器 |
| 英文描述： | Flexible Double Ended Voltage and Current Mode PWM Controllers |
| 中文描述： | 0.5 A SWITCHING CONTROLLER, 2000 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封装： | ROHS COMPLIANT, PLASTIC, MS-012-AC, SOIC-16 |
| 文件页数： | 11/29页 |
| 文件大小： | 635K |
| 代理商： | ISL6741IBZ |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页当前第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页
19
FN9111.4
July 13, 2007
appropriate for this frequency. A value of 220pF was
selected.
Since there is a 10ns propagation delay in the oscillator
circuit, it must be included in the calculation. The value of
RTD selected is 8.06kΩ.
A similar procedure is used to determine the value of RTC using
combination of 17.4k
Ω and 1.27kΩ. See section “Overcurrent
Component Selection” on page 19 for further explanation.
Output Filter Design
The output filter inductor and capacitor selection is simple
and straightforward. Under steady state operating conditions
the voltage across the inductor is very small due to the large
duty cycle. Voltage is applied across the inductor only during
the switch transition time, about 45ns in this application.
Ignoring the voltage drop across the SR FETs, the voltage
across the inductor during the ON time with VIN = 48V is
where
VL is the inductor voltage
VS is the voltage across the secondary winding
VOUT is the output voltage
If we allow a current ramp,
ΔI, of 5% of the rated output
current, the minimum inductance required is
An inductor value of 1.4
μH, rated for 18A was selected.
With a maximum input voltage of 53V, the maximum output
voltage is about 13V. The closest higher voltage rated
capacitor is 16V. Under steady state operating conditions the
ripple current in the capacitor is small, so it would seem
appropriate to have a low ripple current rated capacitor.
However, a high rated ripple current capacitor was selected
based on the nature of the intended load, multiple buck
regulators. To minimize the output impedance of the filter, a
Sanyo OSCON 16SH150M capacitor in parallel with a 22
μF
ceramic capacitor were selected.
Overcurrent Component Selection
There are two circuit areas to consider when selecting the
components for overcurrent protection, current limit and
short circuit shutdown. The current limit threshold is fixed at
0.6V while the short circuit threshold is set to a fraction of the
duty cycle the designer wishes to define as a short circuit.
The current level that corresponds to the overcurrent
threshold must be chosen to allow for the dynamic behavior
of an open loop converter. In particular, the low inductor
ripple current under steady state operation increases
significantly as the duty cycle decreases.
Figures 8 and 9 show the behavior of the inductor ripple
under steady state and overcurrent conditions. In this
example, the peak current limit is set at 11A. The peak
current limit causes the duty cycle to decrease resulting in a
reduction of the average current through the inductor. The
implication is that the converter can not supply the same
output current in current limit that it can supply under steady
state conditions. The peak current limit setpoint must take
this behavior into consideration. A 3.32
Ω current sense
resistor was selected for the rectified secondary of current
transformer T2, corresponding to a peak current limit
setpoint of 16.5A.
The short circuit protection involves setting a voltage
between 0 and 2V on the SCSET pin. The applied voltage
divided by 2 is the percent of maximum duty cycle that
corresponds to a short circuit when the peak current limit is
active. A divider from RTC to ground provides an easy
V
L
V
S
V
OUT
–
V
IN
N
S
1D
–
()
2N
P
------------------------------------------------
250
≈
==
mV
(EQ. 22)
L
V
L
T
ON
ΔI
-------------------------
≥
0.25
2.08
0.5
-----------------------------
1.04
==
μH
(EQ. 23)
FIGURE 8. STEADY STATE SECONDARY WINDING
VOLTAGE AND INDUCTOR CURRENT
14
13
12
11
10
9
8
0.9950
0.9960
0.9970
0.9980
0.9990
1.000
TIME (ms)
V (L1:1)
I (L1)
FIGURE 9. SECONDARY WINDING VOLTAGE AND
INDUCTOR CURRENT DURING CURRENT LIMIT
OPERATION
0.986
0.988
0.990
0.992
0.994
1.000
TIME (ms)
0.996
0.998
15
10
5
V (L1:1)
I (L1)
ISL6740, 1SL6741
相关PDF资料 |
PDF描述 |
|---|---|
| ISL6741IVZ | Flexible Double Ended Voltage and Current Mode PWM Controllers |
| ISL81487EIB-T | 【15kV ESD Protected, 1/8 Unit Load, 5V, Low Power, High Speed or Slew Rate Limited, RS-485/RS-422 Transceivers |
| ISL81487EIBZ-T | 【15kV ESD Protected, 1/8 Unit Load, 5V, Low Power, High Speed or Slew Rate Limited, RS-485/RS-422 Transceivers |
| ISL81487EIB* | 【15kV ESD Protected, 1/8 Unit Load, 5V, Low Power, High Speed or Slew Rate Limited, RS-485/RS-422 Transceivers |
| ISL81487EIBZ* | 【15kV ESD Protected, 1/8 Unit Load, 5V, Low Power, High Speed or Slew Rate Limited, RS-485/RS-422 Transceivers |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6741IBZ-T | 功能描述:IC REG CTRLR PWM CM 16-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL6741IV | 功能描述:IC REG CTRLR PWM CM 16-TSSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:100% 电源电压:8.2 V ~ 30 V 降压:无 升压:无 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:0°C ~ 70°C 封装/外壳:8-DIP（0.300"，7.62mm） 包装:管件 产品目录页面:1316 (CN2011-ZH PDF) |
| ISL6741IV-T | 功能描述:IC REG CTRLR PWM CM 16-TSSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:100% 电源电压:8.2 V ~ 30 V 降压:无 升压:无 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:0°C ~ 70°C 封装/外壳:8-DIP（0.300"，7.62mm） 包装:管件 产品目录页面:1316 (CN2011-ZH PDF) |
| ISL6741IVZ | 功能描述:IC REG CTRLR PWM CM 16-TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL6741IVZ-T | 功能描述:IC REG CTRLR PWM CM 16-TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
发布紧急采购，3分钟左右您将得到回复。