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參數(shù)資料
| 型號(hào)： | ISL6207CRZA |
| 廠(chǎng)商： | INTERSIL CORP |
| 元件分類(lèi)： | 功率晶體管 |
| 英文描述： | Octal D-Type Edge-Triggered Flip-Flops With 3-State Outputs 20-SOIC -40 to 85 |
| 中文描述： | HALF BRDG BASED MOSFET DRIVER, PQCC8 |
| 封裝： | 3 X 3 MM, ROHS COMPLIANT, PLASTIC, QFN-8 |
| 文件頁(yè)數(shù)： | 5/9頁(yè) |
| 文件大?。?/td> | 292K |
| 代理商： | ISL6207CRZA |
5
FN9075.7
July 25, 2005
A falling transition on PWM indicates the turn-off of the upper
MOSFET and the turn-on of the lower MOSFET. A short
propagation delay [t
PDLUGATE
] is encountered before the
upper gate begins to fall [t
FUGATE
]. Again, the adaptive shoot-
through circuitry determines the lower gate delay time
t
PDHLGATE
.
The upper MOSFET gate-to-source v
oltage is
monitored, and the lower gate is allowed to rise, after the
upper MOSFET
gate-to-source voltage
drops belo
w 1
V. The
lower gate then rises [t
RLGATE
], turning on the lower
MOSFET.
This driver is optimized for converters with large step down
ratio, such as those used in a mobile-computer core voltage
regulator. The lower MOSFET is usually sized much larger.
This driver is optimized for converters with large step down
compared to the upper MOSFET because the lower
MOSFET conducts for a much longer time in a switching
period. The lower gate driver is therefore sized much larger
to meet this application requirement. The 0.4
on-resistance
and 4A sink current capability enable the lower gate driver to
absorb the current injected to the lower gate through the
drain-to-gate capacitor of the lower MOSFET and prevent a
shoot through caused by the high dv/dt of the phase node.
Three-State PWM Input
A unique feature of the ISL6207 and other Intersil drivers is
the addition of a shutdown window to the PWM input. If the
PWM signal enters and remains within the shutdown window
for a set holdoff time, the output drivers are disabled and
both MOSFET gates are pulled and held low. The shutdown
state is removed when the PWM signal moves outside the
shutdown window. Otherwise, the PWM rising and falling
thresholds outlined in the ELECTRICAL SPECIFICATIONS
determine when the lower and upper gates are enabled.
During start-up, PWM should be in the three-state position
(1/2 V
CC
). However, with rising V
CC
, the active tracking
elements for PWM are not active until V
CC
> 1.2V, which
leaves PWM in a high impedance (undetermined) state;
therefore, a 500k
resistor must be place from the PWM pin
to GND.
Adaptive Shoot-Through Protection
Both drivers incorporate adaptive shoot-through protection
to prevent upper and lower MOSFETs from conducting
simultaneously and shorting the input supply. This is
accomplished by ensuring the falling gate has turned off one
MOSFET before the other is allowed to turn on.
During turn-off of the lower MOSFET, the LGATE voltage is
monitored until it reaches a 1V threshold, at which time the
UGATE is released to rise. Adaptive shoot-through circuitry
monitors the upper MOSFET gate-to-source voltage during
UGATE turn-off. Once the upper MOSFET gate-to-source
voltage has dropped below a threshold of 1V, the LGATE is
allowed to rise.
Internal Bootstrap Diode
This driver features an internal bootstrap Schottky diode.
Simply adding an external capacitor across the BOOT and
PHASE pins completes the bootstrap circuit.
The bootstrap capacitor must have a maximum voltage
rating above the maximum battery voltage plus 5V. The
bootstrap capacitor can be chosen from the following
equation:
Q
BOOT
where Q
GATE
is the amount of gate charge required to fully
charge the gate of the upper MOSFET. The
V
BOOT
term is
defined as the allowable droop in the rail of the upper drive.
As an example, suppose an upper MOSFET has a gate
charge, Q
GATE
, of 25nC at 5V and also assume the droop in
the drive voltage over a PWM cycle is 200mV. One will find
that a bootstrap capacitance of at least 0.125
μ
F is required.
PWM
UGATE
LGATE
t
PDLLGATE
t
FLGATE
t
PDHUGATE
t
RUGATE
t
PDLUGATE
t
FUGATE
t
PDHLGATE
t
RLGATE
1V
1V
FIGURE 1. TIMING DIAGRAM
C
BOOT
-----------------------
≥
ISL6207
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ISL6207HBZ | PT 10C 10#20 PIN/SKT RECP |
| ISL6207HBZ-T | PT 14C 14#20 PIN/SKT RECP |
| ISL6207CR-T | High Voltage Synchronous Rectified Buck MOSFET Driver |
| ISL6207HRZ | High Voltage Synchronous Rectified Buck MOSFET Driver |
| ISL6207HRZ-T | High Voltage Synchronous Rectified Buck MOSFET Driver |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ISL6207CRZA-T | 制造商:INTERSIL 制造商全稱(chēng):Intersil Corporation 功能描述:High Voltage Synchronous Rectified Buck MOSFET Driver |
| ISL6207CRZ-T | 功能描述:功率驅(qū)動(dòng)器IC VER OF ISL6207CR-T RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類(lèi)型:Low Cost High or Low Side MOSFET Driver 上升時(shí)間: 下降時(shí)間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| ISL6207HBZ | 功能描述:功率驅(qū)動(dòng)器IC VER OF ISL6207CB W/- 10 TO +100 TEMP RNG RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類(lèi)型:Low Cost High or Low Side MOSFET Driver 上升時(shí)間: 下降時(shí)間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| ISL6207HBZ-T | 功能描述:功率驅(qū)動(dòng)器IC VER OF ISL6207CB-T W /-10 TO +100 TEMP RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類(lèi)型:Low Cost High or Low Side MOSFET Driver 上升時(shí)間: 下降時(shí)間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| ISL6207HRZ | 功能描述:功率驅(qū)動(dòng)器IC VER OF ISL6207CR -10 TO +100 RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類(lèi)型:Low Cost High or Low Side MOSFET Driver 上升時(shí)間: 下降時(shí)間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
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