- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383148 > ISL6439CBZ (INTERSIL CORP) Single Sync Buck PWM Controller for Broadband Gateway Applications PDF資料下載
參數(shù)資料
| 型號： | ISL6439CBZ |
| 廠商： | INTERSIL CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Single Sync Buck PWM Controller for Broadband Gateway Applications |
| 中文描述： | SWITCHING CONTROLLER, 325 kHz SWITCHING FREQ-MAX, PDSO14 |
| 封裝： | LEAD FREE, PLASTIC, MS-012-AB, SOIC-14 |
| 文件頁數(shù)： | 12/15頁 |
| 文件大?。?/td> | 379K |
| 代理商： | ISL6439CBZ |
12
Some capacitor series available from reputable manufacturers
are surge current tested.
MOSFET Selection/Considerations
The ISL6439 requires two N-Channel power MOSFETs.
These should be selected based upon r
DS(ON)
, gate supply
requirements, and thermal management requirements.
In high-current applications, the MOSFET power dissipation,
package selection and heatsink are the dominant design
factors. The power dissipation includes two loss components;
conduction loss and switching loss. The conduction losses are
the largest component of power dissipation for both the upper
and the lower MOSFETs. These losses are distributed between
the two MOSFETs according to duty factor. The switching
losses seen when sourcing current will be different from the
switching losses seen when sinking current. When sourcing
current, the upper MOSFET realizes most of the switching
losses. The lower switch realizes most of the switching losses
when the converter is sinking current (see equations on next
page). These equations assume linear voltage-current
transitions and do not adequately model power loss due the
reverse-recovery of the upper and lower MOSFET’s body
diode. The gate-charge losses are dissipated by the ISL6439
and don't heat the MOSFETs. However, large gate-charge
increases the switching interval, t
SW
which increases the
MOSFET
switching losses. Ensure that both MOSFETs are
within their maximum junction temperature at high ambient
temperature by calculating the temperature rise according to
package thermal-resistance specifications. A separate heatsink
may be necessary depending upon MOSFET power, package
type, ambient temperature and air flow.
Given the reduced available gate bias voltage (5V), logic-
level or sub-logic-level transistors should be used for both N-
MOSFETs. Caution should be exercised with devices
exhibiting very low V
GS(ON)
characteristics. The shoot-
through protection present aboard the ISL6439 may be
circumvented by these MOSFETs if they have large parasitic
impedences and/or capacitances that would inhibit the gate
of the MOSFET from being discharged below its threshold
level before the complementary MOSFET is turned on.
Bootstrap Component Selection
External bootstrap components, a diode and capacitor, are
required to provide sufficient gate enhancement to the upper
MOSFET. The internal MOSFET gate driver is supplied by
the external bootstrap circuitry as shown in Figure 7. The
boot capacitor, C
BOOT
, develops a floating supply voltage
referenced to the PHASE pin. This supply is refreshed each
cycle, when D
BOOT
conducts, to a voltage of CPVOUT less
the boot diode drop, V
D
, plus the voltage rise across
Q
LOWER
.
Just after the PWM switching cycle begins and the charge
transfer from the bootstrap capacitor to the gate capacitance
is complete, the voltage on the bootstrap capacitor is at its
lowest point during the switching cycle. The charge lost on
the bootstrap capacitor will be equal to the charge
transferred to the equivalent gate-source capacitance of the
upper MOSFET as shown:
where Q
GATE
is the maximum total gate charge of the upper
MOSFET, C
BOOT
is the bootstrap capacitance, V
BOOT1
is
the bootstrap voltage immediately before turn-on, and
V
BOOT2
is the bootstrap voltage immediately after turn-on.
The bootstrap capacitor begins its refresh cycle when the gate
drive begins to turn-off the upper MOSFET. A refresh cycle
ends when the upper MOSFET is turned on again, which
varies depending on the switching frequency and duty cycle.
The minimum bootstrap capacitance can be calculated by
rearranging the previous equation and solving for C
BOOT
.
Typical gate charge values for MOSFETs considered in
these types of applications range from 20 to 100nC. Since
the voltage drop across Q
LOWER
is negligible, V
BOOT1
is
simply V
CPVOUT
- V
D
. A schottky diode is recommended to
P
LOWER
= Io
2
x r
DS(ON)
x (1 - D)
Where: D is the duty cycle = V
OUT
/ V
IN
,
t
SW
is the combined switch ON and OFF time, and
f
s
is the switching frequency.
Losses while Sourcing current
Io
2
=
Losses while Sinking current
P
UPPER
= Io
2
x r
DS(ON)
x D
P
LOWER
Io
2
r
DS ON
)
×
1
D
–
(
)
×
1
2
--
Io
V
IN
×
t
SW
f
s
×
×
+
=
P
UPPER
r
DS ON
)
×
D
×
1
2
--
Io
V
IN
×
t
SW
f
s
×
×
+
ISL6439
GND
LGATE
UGATE
PHASE
BOOT
V
IN
NOTE:
V
G-S
= V
CC
-V
D
NOTE:
V
G-S
= V
CC
C
BOOT
D
BOOT
Q
UPPER
Q
LOWER
+
FIGURE 7. UPPER GATE DRIVE BOOTSTRAP
+
V
D
-
CPVOUT
Q
GATE
C
BOOT
V
BOOT1
V
BOOT2
–
(
)
×
=
C
BOOT
Q
–
V
BOOT1
V
BOOT2
----------------------------------------------------
=
ISL6439
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ISL6439CR | Single Sync Buck PWM Controller for Broadband Gateway Applications |
| ISL6439IR | Single Sync Buck PWM Controller for Broadband Gateway Applications |
| ISL6439AEVAL1 | Single Sync Buck PWM Controller for Broadband Gateway Applications |
| ISL6439AEVAL2 | Single Sync Buck PWM Controller for Broadband Gateway Applications |
| ISL6439AIB-T | Circular Connector; No. of Contacts:3; Series:MS27473; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:12; Circular Contact Gender:Pin; Circular Shell Style:Straight Plug; Insert Arrangement:12-3 RoHS Compliant: No |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ISL6439CBZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 14-SOIC 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) |
| ISL6439CR | 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Intersil Corporation 功能描述: |
| ISL6439CR-T | 制造商:Rochester Electronics LLC 功能描述:- Tape and Reel 制造商:Intersil Corporation 功能描述: |
| ISL6439EVAL1 | 功能描述:EVALUATION BOARD 1 ISL6439 RoHS:否 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - DC/DC 與 AC/DC（離線）SMPS 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:True Shutdown™ 主要目的:DC/DC，步升 輸出及類型:1，非隔離 功率 - 輸出:- 輸出電壓:- 電流 - 輸出:1A 輸入電壓:2.5 V ~ 5.5 V 穩(wěn)壓器拓?fù)浣Y(jié)構(gòu):升壓 頻率 - 開關(guān):3MHz 板類型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| ISL6439IB | 功能描述:IC REG CTRLR BUCK PWM VM 14-SOIC 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:4,000 系列:- PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1.5MHz 占空比:66.7% 電源電壓:4.75 V ~ 5.25 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 85°C 封裝/外殼:40-VFQFN 裸露焊盤 包裝:帶卷 (TR) |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。