- 您现在的位置：买卖IC网 > Sheet目录17337 > ISL6527AEVAL2 (Intersil)EVALUATION BOARD QFN ISL6527A
ISL6527, ISL6527A
The minimum bootstrap capacitance can be calculated by
CPVOUT
rearranging Equation 19 and solving for CBOOT in
C BOOT ≥ -----------------------------------------------------
ISL6527,
ISL6527A
DBOOT
BOOT
+
V D
-
CBOOT
VIN
Equation 20.
Q GATE
V BOOT1 – V BOOT2
(EQ. 20)
UGATE
PHASE
Q UPPER
NOTE:
V G-S ≈ V CC -V D
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
-
+
LGATE
GND
Q LOWER
NOTE:
V G-S ≈ V CC
simply V CPVOUT - V D . A schottky diode is recommended to
minimize the voltage drop across the bootstrap capacitor
during the on-time of the upper MOSFET. Initial calculations
with V BOOT2 no less than 4V will quickly help narrow the
bootstrap capacitor range.
FIGURE 7. UPPER GATE DRIVE BOOTSTRAP
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 in Equation 19:
For example, consider an upper MOSFET is chosen with a
maximum gate charge, Q g , of 100nC. Limiting the voltage
drop across the bootstrap capacitor to 1V results in a value
of no less than 0.1μF. The tolerance of the ceramic capacitor
should also be considered when selecting the final bootstrap
capacitance value.
A fast recovery diode is recommended when selecting a
bootstrap diode to reduce the impact of reverse recovery
Q GATE = C BOOT × ( V BOOT1 – V BOOT2 )
(EQ. 19)
charge loss. Otherwise, the recovery charge, Q RR , would
have to be added to the gate charge of the MOSFET and
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.
13
taken into consideration when calculating the minimum
bootstrap capacitance.
ISL6527, ISL6527A DC/DC Converter
Application Circuit
Figure 8 shows an application circuit of a DC/DC Converter.
Detailed information on the circuit, including a complete
Bill-of-Materials and circuit board description, can be found
in Application Note AN1021.
FN9056.10
November 18, 2008
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
594D476X0010B8T
CAP TANT 47UF 10V 20% 1611
695D106X9015D2T
CAP TANT 10UF 15V 10% 1810
RBM10DCTD-S288
CONN EDGECARD 20POS .156 EXTEND
594D107X96R3B8T
CAP TANT 100UF 6.3V 10% 1611
EL7566DRE-EVAL
DEMO BOARD FOR EL7566
HK100539NJ-T
INDUCTOR HI FREQ 39NH 5% 0402
A9BBA-1106F
FLEX CABLE - AFF11A/AF11/AFF11A
695D106X9006D2T
CAP TANT 10UF 6V 10% 1810
相关代理商/技术参数
ISL6527AIB
功能描述:IC REG CTRLR BST PWM VM 14-SOIC 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: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)
ISL6527AIB-T
功能描述:IC REG CTRLR BST PWM VM 14-SOIC 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: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)
ISL6527AIBZ
制造商:Rochester Electronics LLC 功能描述: 制造商:Intersil Corporation 功能描述:
ISL6527AIR
功能描述:IC REG CTRLR BST PWM VM 16-QFN 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: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)
ISL6527AIR-T
功能描述:IC REG CTRLR BST PWM VM 16-QFN 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: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)
ISL6527AIRZ
功能描述:电压模式 PWM 控制器 600KHZ SNG PWM CONTR LR W/EXT. REF. 16LD RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel
ISL6527AIRZ-T
功能描述:IC REG CTRLR BST PWM VM 16-QFN 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)
ISL6527CB
功能描述:电压模式 PWM 控制器 Single Synch Buck
RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel