High-Speed, Dual-Phase Driver
with Integrated Boost Diodes
Detailed Description
Principles of Operation
Table 1. Components for Figure 3, 800kHz,
20A/Phase Typical Application Circuit
MOSFET Gate Drivers (DH_, DL_)
DH_ is driven high when the PWM_ is high; DL_ is dri-
ven high when PWM_ is low. PWM pulsewidths under
20ns (typ) are rejected, and no switching occurs.
The low-side drivers (DL_) have typical 0.9 Ω sourcing
resistance and 0.4 Ω sinking resistance, and are capable
of driving 3000pF capacitive loads with 11ns typical rise
and 8ns typical fall times. The high-side drivers (DH_)
have typical 1.0 Ω sourcing resistance and 0.7 Ω sinking
resistance, and are capable of driving 3000pF capaci-
tive loads with 14ns typical rise and 9ns typical fall times.
This facilitates fast switching, reducing switching losses,
and makes the MAX8811 ideal for both high-frequency
and high-output current applications.
Shoot-Through Protection
Adaptive shoot-through protection is incorporated for
the switching transition after the high-side MOSFET is
turned off and before the low-side MOSFET is turned
on. The low-side driver is turned on when the LX volt-
age falls below 2.5V, or after 135ns typical delay,
whichever occurs first. Furthermore, the delay time
between the low-side MOSFET turn-off and high-side
MOSFET turn-on can be adjusted by selecting the
value of R1 (see the Setting the Dead Time section).
Undervoltage Lockout (UVLO)
When the voltage at the VL1/VL2 connection is below
the UVLO threshold, all driver outputs are held low. This
prevents switching when the supply voltage is too low
for proper operation.
Thermal Protection
Thermal-overload protection limits total power dissipa-
tion in the MAX8811. When the junction temperature
DESIGNATION
C1
C2
C3
C4, C5
C6–C9
L1, L2
Q1, Q3
Q2
Q4
R1
DESCRIPTION
2 x 10μF ±20%, X7R
25V capacitor
12103D106MAT2W
2 x 10μF ±20%, X7R
25V capacitor
12103D106MAT2W
2.2μF ±20%, 10V X5R
capacitor
GRM39X5R225K10
0.22μF ±20%, 10V
X7R capacitors
GRM39X7R224K10
100μF ±20%, 6.3V
X5R capacitors
C3225X5R0J107M
0.2μH, 28A inductors
FDV0630-
R20M,1.9m Ω DCR
HAT2168, 8m Ω , 30V
MOSFET
2 x HAT2164H, 3m Ω ,
30V, MOSFET
2 x HAT2164H, 3m Ω ,
30V MOSFET
Dead-time delay
programming resistor;
see Programmable
Delay vs. R DLY in the
Typical Operating
Characteristics
MANUFACTURER
AVX
AVX
Murata
Murata
TDK
TOKO
Renesas
Renesas
Renesas
exceeds +165°C, all driver outputs are held low. The IC
resumes normal operation after the junction tempera-
ture cools by 15°C (typ).
Boost Capacitor Selection
The MAX8811 uses a bootstrap circuit to generate the
supply voltages for the high-side drivers (DH_). The select-
ed high-side MOSFET determines the appropriate boost
capacitance values, according to the following equation:
where Q GATE is the total gate charge of the high-side
MOSFET and Δ V BST is the voltage variation allowed on
the high-side MOSFET drive. Choose Δ V BST = 0.1V to
0.2V when determining C BST . Low-ESR ceramic capaci-
tors should be used.
VL_ Decoupling
VL1 and VL2 provide the supply voltage for the low-side
drivers. The decoupling capacitors at VL_ also charge the
C BST =
Q GATE
Δ V BST
BST capacitors during the time period when DL_ is high.
Therefore, the decoupling capacitor C3 for VL_ should be
large enough to minimize the ripple voltage during
switching transitions. Choose the VL capacitor approxi-
mately 10 times the value of the BST capacitor value.
_______________________________________________________________________________________
7
相关PDF资料
MAX8821ETI+ IC LED DRVR WHITE BCKLGT 28-TQFN
MAX8822ETE+T IC LED DRVR WHITE BCKLGT 16-TQFN
MAX8830EWE+T IC LED DRVR WHITE BCKLGT 16-UCSP
MAX8831EWE+T IC LED DRIVR WHITE BCKLGT 16-WLP
MAX8834ZEWP+T IC LED DRIVR BCKLGT FLASH 20-WLP
MAX8855EVKIT+ KIT EVAL FOR MAX8855
MAX8879ETG+T IC LED DRVR WT/RGB BCKLGT 24TQFN
MAX8901BETA+TCH8 IC LED DRIVER WHITE BCKLGT 8TDFN
相关代理商/技术参数
MAX8811EEE+T 功能描述:功率驱动器IC High-Speed Dual Phase Driver RoHS:否 制造商:Micrel 产品:MOSFET Gate Drivers 类型:Low Cost High or Low Side MOSFET Driver 上升时间: 下降时间: 电源电压-最大:30 V 电源电压-最小:2.75 V 电源电流: 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube
MAX8814ETA+ 制造商:Maxim Integrated Products 功能描述:CHGR LI-ION/LI-POL 570MA 4.2V 8TDFN EP - Rail/Tube 制造商:Rochester Electronics LLC 功能描述:
MAX8814ETA+T 功能描述:电池管理 28V Linear Li+ Battery Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel
MAX8814EVKIT+ 功能描述:电源管理IC开发工具 MAX8814 Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V
MAX8815AETB+ 制造商:Maxim Integrated Products 功能描述:1A 97% EFFICIENCY 30UA QUIESCENT 制造商:Maxim Integrated Products 功能描述:1A, 97% EFFICIENCY, 30?A QUIESCENT CURRENT, STEP-UP CONVERTE - Bulk
MAX8815AETB+T 功能描述:直流/直流开关转换器 Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT
MAX8815AEVKIT+ 功能描述:DC/DC 开关控制器 Evaluation Kit for the MAX8815A RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
MAX8818AETM+ 功能描述:PMIC 解决方案 10Ch PMIC for 2-Cell Li+ DVC System RoHS:否 制造商:Texas Instruments 安装风格:SMD/SMT 封装 / 箱体:QFN-24 封装:Reel