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| 型号： | MAX5053BEUA+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 7/13页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BST ISO PWM 8-UMAX |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 50 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 290kHz |
| 占空比： | 76% |
| 电源电压： | 10.8 V ~ 24 V |
| 降压： | 无 |
| 升压： | 是 |
| 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-TSSOP，8-MSOP（0.118"，3.00mm 宽） |
| 包装： | 管件 |
Current-Mode PWM Controllers with an Error
Amplifier for Isolated/Nonisolated Power Supplies
D1
T1
(max). V IN is the value of the input-supply voltage
where the power supply must start.
V IN ? V ULR 2
V SUPPLY
R1
R2
D2
C4
V OUT
R 2 = × R 3
V ULR 2
Q1
V IN
NDRV
R5
where I UVLO is the UVLO/EN pin input current (50nA),
C1
V CC MAX5052
CS
and V ULR2 is the UVLO/EN wake-up threshold.
C2
C3
COMP
GND
R4
R6
MAX5052 Bootstrap
Undervoltage Lockout
0V
FB
UVLO/EN
R3
In addition to the externally programmable UVLO func-
tion offered in both the MAX5052 and MAX5053, the
MAX5052 has an additional internal bootstrap UVLO
that is very useful when designing high-voltage power
supplies (see the Functional Diagram ). This allows the
device to bootstrap itself during initial power-up. The
Figure 1. Nonisolated Power Supply with Programmable Input-
Supply Start Voltage
the power dissipation across R1 even at the high end of
the universal AC input voltage (265VAC).
The MAX5052/MAX5053 include a cycle-by-cycle cur-
rent limit that turns off the gate drive to the external
MOSFET during an overcurrent condition. When using
the MAX5052 in the bootstrapped mode (if the power-
supply output is shorted), the tertiary winding voltage
drops below the 10V threshold causing the UVLO to
turn off the gate drive to the external power MOSFET.
This reinitiates a startup sequence with soft-start.
MAX5052/MAX5053
Undervoltage Lockout
The MAX5052/MAX5053 have an input voltage
UVLO/EN pin. The threshold for this UVLO is 1.28V.
Before any operation can commence, the voltage on
this pin has to exceed 1.28V. The UVLO circuit keeps
the CPWM comparator, ILIM comparator, oscillator,
and output driver shut down to reduce current con-
sumption (see the Functional Diagram ).
Use this UVLO function to program the input-supply
start voltage. For example, a reasonable start voltage
for a 36V to 72V telecom range might be set at 34V.
Calculate the divider resistor values, R2 and R3 (see
Figure 1) by using the following formulas:
MAX5052 attempts to start when V IN exceeds the boot-
strap UVLO threshold of 21.6V.
During startup, the UVLO circuit keeps the CPWM com-
parator, ILIM comparator, oscillator, and output driver
shut down to reduce current consumption. Once V IN
reaches 21.6V, the UVLO circuit turns on both the CPWM
and ILIM comparators, as well as the oscillator, and
allows the output driver to switch. If V IN drops below
9.7V, the UVLO circuit will shut down the CPWM com-
parator, ILIM comparator, oscillator, and output driver
returning the MAX5052/MAX5053 to the startup mode.
MAX5052 Startup Operation
Normally V IN is derived from a tertiary winding of the
transformer. However, at startup there is no energy
delivered through the transformer, hence, a special
bootstrap sequence is required. Figure 2 shows the
voltages on V IN and V CC during startup. Initially, both
V IN and V CC are 0V. After the line voltage is applied,
C1 charges through the startup resistor, R1, to an inter-
mediate voltage. At this point, the internal regulator
begins charging C2 (see Figure 1). The MAX5052 uses
only 45μA of the current supplied by R1, and the
remaining input current charges C1 and C2. The charg-
ing of C2 stops when the V CC voltage reaches approxi-
mately 9.5V, while the voltage across C1 continues
rising until it reaches the wake-up level of 21.6V. Once
V IN exceeds the bootstrap UVLO threshold, NDRV
begins switching the MOSFET and transfers energy to
R 3 ?
V ULR 2 × V IN
500 × I UVLO ( V IN ? V ULR 2 )
the secondary and tertiary outputs. If the voltage on the
tertiary output builds to higher than 9.9V (the bootstrap
UVLO lower threshold), then startup has been accom-
The value of R3 is calculated to minimize the voltage-
drop error across R2 as a result of the input bias cur-
rent of the UVLO/EN pin. V ULR2 = 1.28V, I UVLO = 50nA
plished and sustained operation commences.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX5053BEUA+ | 功能描述:电流型 PWM 控制器 w/Error Amplifier RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX5053BEUA+T | 功能描述:电流型 PWM 控制器 w/Error Amplifier RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX5053BEUA-T | 功能描述:电流型 PWM 控制器 w/Error Amplifier RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX5054 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:4A, 20ns, Dual MOSFET Drivers |
| MAX5054_10 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:4A, 20ns, Dual MOSFET Drivers |
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