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参数资料
| 型号： | MAX5042EVKIT |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 13/22页 |
| 文件大小： | 0K |
| 描述： | EVAL KIT FOR MAX5042 |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 1，隔离 |
| 输出电压： | 5V |
| 电流 - 输出： | 8A |
| 输入电压： | ±36 V ~ 75 V |
| 稳压器拓扑结构： | 降压 |
| 频率 - 开关： | 250kHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | MAX5042 |
Two-Switch Power ICs with Integrated
Power MOSFETs and Hot-Swap Controller
Power Topology
The two-switch forward-converter topology offers out-
+V POSINPWM
standing robustness against faults and transformer satu-
MAX5043
QH
C IN
BULK STORAGE CAPACITOR
L
ration while affording efficient use of the integrated
75m ? power MOSFETs. Voltage-mode control with feed-
forward compensation allows the rejection of input sup-
ply disturbances within a single cycle similar to that of
QL
PWM
CIRCUIT
WITH
INTEGRATED
FETs
T1
V OUT
C OUT
current-mode controlled topologies. This control method
offers some significant benefits when compared with
current-mode control. These benefits include:
? No minimum duty-cycle requirement due to current-
signal filtering or blanking.
? Clean modulator ramp and higher amplitude for
increased stability.
PWMNEG
Figure 2. Simplified Diagram of a MAX5043-Based Isolated
Power Supply
Set the switching frequency with a resistor and a
capacitor at RCOSC. Switching at 250kHz ensures
switching losses are minimal and external power pas-
sives are small enough for a compact circuit.
The MAX5042/MAX5043 incorporate an advanced set of
protection features that make them uniquely suitable
when high reliability and comprehensive fault protection
are required, as in telecommunication equipment power-
supply applications. The MAX5042/MAX5043 15V linear
regulator output powers the 9V and 5V regulators used to
drive the gates and internal circuitry. A tertiary winding
connects to REG15 through a rectifier to power the
device after startup and reduces power dissipation in the
MAX5042/MAX5043 package. When REG15 is externally
powered, the internal 15V regulator is disabled.
Figures 3 and 4 show the block diagrams of the MAX5042
and MAX5043, respectively. The power-OK signals from
the hot-swap section, regulators, thermal shutdown, and
UVLO combine to generate the internal shutdown signal
SHDN. When asserted, SHDN disables the comparators
and oscillator. Deasserting SHDN releases the compara-
tors and oscillators. The falling edge of SHDN is delayed
allowing the internal signals to settle before the PWM puls-
es appear. During the time between the falling edge of
SHDN and its delayed signal, the 10 ? internal MOSFET
(QB) from XFRMRH to PWMPNEG turns on, charging the
BST capacitor. After startup, this MOSFET also turns on
for approximately 300ns at each half period to help
? Stable bias point of the optocoupler LED and photo-
transistor for maximized control-loop bandwidth (in
current-mode applications, the optocoupler bias
point is output-load dependent).
? Predictable loop dynamics simplifying the design of
the control loop.
The two-switch power topology recovers energy stored
in both the magnetizing and parasitic leakage induc-
tances of the transformer. Figure 7 shows the schemat-
ic diagram of a 48V input and 5V, 8A output isolated
power supply built with the MAX5042.
The MAX5042/MAX5043 also support current-mode con-
trol. Current-mode control has advantages such as a sin-
gle-pole power circuit and a small-signal transfer
function that simplify the design of power supplies with
widely varying output capacitors.
Undervoltage Lockout
The MAX5042 has two UVLO functions. Both the hot-
swap section and the PWM section contain their own
undervoltage lockout comparators (HSEN and UVLO,
respectively). The MAX5043 lacks the hot-swapping
function, but retains the PWM UVLO and the deglitched
undervoltage lockout/power-on reset. In both cases,
internal resistors set a default input-voltage enable
threshold of 31V (typ).
The PWM default input voltage threshold value can be
adjusted by using an external divider in parallel with the
internal divider. The tolerances of the external divider
resistors dominate the precision of the UVLO trip point if
their values are smaller than those of the internal divider.
Override the default threshold by using:
charge the BST capacitor.
R He =
R Le × R Li × R Hi × ( V IN - V REF )
V REF × R Hi ( R Li + R Le ) - R Le × R Li × ( V IN - V REF )
______________________________________________________________________________________
13
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX5043ATN+ | 制造商:Maxim Integrated Products 功能描述:- Rail/Tube |
| MAX5043ETN | 功能描述:开关变换器、稳压器与控制器 Two-Switch Power IC w/Power MOSFET RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
| MAX5043ETN+ | 功能描述:开关变换器、稳压器与控制器 Two-Switch Power IC w/Power MOSFET RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
| MAX5043ETN+T | 功能描述:开关变换器、稳压器与控制器 Two-Switch Power IC w/Power MOSFET RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
| MAX5043ETN-T | 功能描述:开关变换器、稳压器与控制器 Two-Switch Power IC w/Power MOSFET RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
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