參數(shù)資料
型號(hào)： ISL6741IV
廠商： INTERSIL CORP
元件分類： 穩(wěn)壓器
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
封裝： PLASTIC, MO-153-AB, TSSOP-16
文件頁數(shù)： 13/29頁
文件大小： 639K
代理商： ISL6741IV
13
The voltage hysteresis created by the switched current
source and the external impedance is generally small due to
the large resistor divider ratio required to scale the input
voltage down to the UV threshold level. A small capacitor
placed between the UV input and ground may be required to
filter noise out.
As V
IN
decreases to a UV condition, the threshold level is:
The hysteresis voltage,
V, is:
Setting R3 equal to zero results in the minimum hysteresis,
and yields:
As V
IN
increases from a UV condition, the threshold level is:
Over Current Operation
ISL6740 -
Over current delayed shutdown is enabled once
the soft start cycle is complete. If an over current condition is
detected, the soft start charging current source is disabled
and the soft start capacitor is allowed to discharge through a
15
μ
A source. At the same time a 50
μ
s re-triggerable one-
shot timer is activated. It remains active for 50
μ
s after the
over current condition ceases. If the soft start capacitor
discharges by more then 0.25V to 4.25V, the output is
disabled and the Fault signal asserted. This state continues
until the soft start voltage reaches 270mV, at which time a
new soft start cycle is initiated. If the over current condition
stops at least 50
μ
s prior to the soft start voltage reaching
4.25V, the soft start charging currents revert to normal
operation and the soft start voltage is allowed to recover.
The duration of the OC shutdown period can be increased
by adding a resistor between VREF and SS. The value of the
resistor must be large enough so that the minimum specified
SS discharge current is not exceeded. Using a 422k
resistor, for example, will result in a small current being
injected into SS, effectively reducing the discharge current.
This will increase the OFF time by about 60%, nominally.
The external pull-up resistor will also decrease the SS
duration, so its effect should be considered when selecting
the value of the SS capacitor.
Latching OC shutdown is also possible by using a lower
valued resistor between VREF and SS. If the SS node is not
allowed to discharge below the SS reset threshold, the IC
will not recover from an over-current fault. The value of the
resistor must be low enough so that the maximum specified
discharge current is not sufficient to pull SS below 0.33V. A
200k
resistor, for example, prevents SS from discharging
below ~0.4V. Again, the external pull-up resistor will
decrease the SS duration, so its effect should be considered
when selecting the value of the SS capacitor.
ISL6741 -
Over current results in pulse-by-pulse duty cycle
reduction as occurs in any peak current mode controller. This
results in a well controlled decrease in output voltage with
increasing current beyond the over current threshold. An over
current condition in the ISL6741 will not cause a shutdown.
Short Circuit Operation
A short circuit condition is defined as the simultaneous
occurrence of current limit and a reduced duty cycle. The
degree of reduced duty cycle is user adjustable using the
SCSET input. A resistor divider between either R
TD
or R
TC
and GND to RCSET sets a threshold that is compared to the
voltage on the timing capacitor, C
T
. The resistor divider
percentage corresponds to the fraction of the maximum duty
cycle below which a short circuit may exist. If the timing
capacitor voltage fails to exceed the threshold before an over
current pulse is detected, a short circuit condition exists. A
shutdown and soft start cycle will begin if 8 short circuit
events occur within 32 oscillator cycles. Connecting SCSET
to GND disables this feature.
Since the current sourced from both R
TC
and R
TD
determine
the charge and discharge currents for the timing capacitor,
the effect of the SCSET divider must be included in the
timing calculations. Typically the resistor between R
TC
and
GND is formed by two series resistors with the center node
connected to SCSET.
Alternatively, SCSET may be set using a voltage between 0V
and 2V. This voltage divided by 2 determines the percentage
of the maximum duty cycle that corresponds to a short circuit
when current limit is active. For example, if the maximum
duty cycle is 95% and 1V is applied to SCSET, then the short
circuit duty cycle is 50% of 95% or 47.5%.
FIGURE 5. UV HYSTERESIS
V
IN
R1
R2
R3
1.00V
10
μ
A
ON
+
-
V
IN DOWN
(
)
--------+
=
V
(EQ. 7)
V
10
5
–
R1
R3
--------+
+
=
V
(EQ. 8)
V
10
5
–
R1
=
V
(EQ. 9)
V
IN UP
(
)
V
IN DOWN
(
)
V
+
=
V
(EQ. 10)
ISL6740, ISL6741
相關(guān)PDF資料
PDF描述
ISL6740 Flexible Double Ended Voltage and Current Mode PWM Controllers
ISL6740IB Flexible Double Ended Voltage and Current Mode PWM Controllers
ISL6740IV Octal Buffers/Drivers With 3-State Outputs 20-SSOP -40 to 85
ISL6741 Flexible Double Ended Voltage and Current Mode PWM Controllers(靈活的雙端電壓和電流模式PWM控制器)
ISL6845IB Improved Industry Standard Single Ended Current Mode PWM Controller
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ISL6741IV-T 功能描述:IC REG CTRLR PWM CM 16-TSSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:100% 電源電壓:8.2 V ~ 30 V 降壓:無 升壓:無 回掃:是 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:是 工作溫度:0°C ~ 70°C 封裝/外殼:8-DIP（0.300"，7.62mm） 包裝:管件 產(chǎn)品目錄頁面:1316 (CN2011-ZH PDF)
ISL6741IVZ 功能描述:IC REG CTRLR PWM CM 16-TSSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:275kHz 占空比:50% 電源電壓:18 V ~ 110 V 降壓:無 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:是 工作溫度:-40°C ~ 85°C 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR)
ISL6741IVZ-T 功能描述:IC REG CTRLR PWM CM 16-TSSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:275kHz 占空比:50% 電源電壓:18 V ~ 110 V 降壓:無 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:是 工作溫度:-40°C ~ 85°C 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR)
ISL6742AAZA 功能描述:IC REG CTRLR PWM CM/VM 16-QSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:75 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.3 V ~ 13.5 V 降壓:是 升壓:是 回掃:是 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:0°C ~ 70°C 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:管件 產(chǎn)品目錄頁面:1051 (CN2011-ZH PDF) 其它名稱:296-2543-5
ISL6742AAZA-T 功能描述:IC REG CTRLR PWM CM/VM 16-QSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:275kHz 占空比:50% 電源電壓:18 V ~ 110 V 降壓:無 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:是 工作溫度:-40°C ~ 85°C 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR)
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。

采購需求

(若只采購一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購

我的聯(lián)系方式

*
*
*