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Maxim MAX17499电流模式PWM电源控制方案
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Maxim公司的MAX17499是电流模式PWM控制器,包含了宽输入电压绝缘和非绝缘电源所需的所有电路.输入电压9.5V DC 到24V DC,通用输入电压(85VAC-265VAC)整流或-36V到-72VDC的通信电压.可编程开关频率高达625kHz,主要用在1/2,1/4和1/8砖电源模块,高效绝缘通信电源,网络/服务器,12V升压和SEPIC稳压器, 绝缘和非绝缘HB
led
,工业电源等.本文介绍了MAX17499主要特性,方框图, 次级调整和初级调整的电源等多种电源电路图.
The MAX17499/MAX17500 current-mode PWM controllers contain all the control circuitry required for the design of wide-input-voltage isolated and nonisolated power supplies. The MAX17499 is w EL l suited for low input voltage (9.5V DC to 24V DC) power supplies. The MAX17500 is well suited for universal input (rectified 85V AC to 265V AC) or telecom (-36V DC to -72V DC) power supplies.
The ICs contain an internal error amplifier that regulates the tertiary winding output voltage that is used in primary-side-regulated isolated power supplies. Primary-side regulation eliminates the need for an optocoupler. An input undervoltage lockout (UVLO) is provided for programming the input-supply start voltage and to ensure proper operation during brownout conditions. An opendrain UVLO flag output, with 210μs internal delay,allows the sequencing of a secondary-side controller.
The input-supply start voltage is externally programmable with a voltage-divider.A UVLO/EN input is used to shut down the devices. Internal digital soft-start eliminates
output voltage overshoot.
The MAX17500 has an internal bootstrap UVLO with large hysteresis that requires a minimum 23.6V for startup. The MAX17499 does not have the internal bootstrap UVLO and can be biased directly from a minimum voltage of 9.5V.
The switching frequency for the ICs is programmable with an external resistor. The MAX17499A/MAX17500A provide a 50% maximum duty-cycle limit, while the MAX17499B/MAX17500B provide a 75% maximum duty-cycle limit. These devices are available in 10-pin μMAX packages and are rated for operation over the -40℃ to +85℃ temperature range.
MAX17499主要特性:
_ Current-Mode Control
_ Programmable Switching Frequency Up to 625kHz
_ Accurate UVLO Threshold (1%)
_ Open-Drain UVLO Flag Output with Internal Delay
_ 36V to 72V Telecom Voltage Range
_ Universal Offline Input Voltage Range Rectified 85V AC to 265V AC (MAX17500)
_ 9.5V to 24V Input (MAX17499)
_ Digital Soft-Start
_ Internal Bootstrap UVLO with Large Hysteresis (MAX17500)
_ Internal Error Amplifier with 1.5% Accurate Reference
_ 50μA (typ) Startup Supply Current
_ 50% Maximum Duty-Cycle Limit (MAX17499A/MAX17500A)
_ 75% Maximum Duty-Cycle Limit (MAX17499B/MAX17500B)
_ 60ns Cycle-by-Cycle Current-Limit Propagation Delay
_ Available in Tiny 10-Pin μMAX Packages
MAX17499应用:
1/2, 1/4, and 1/8 Brick Power Modules
High-Efficiency, Isolated Telecom Power
Supplies
Networking/Servers
Isolated Keep-Alive Power Supplies
12V Boost and SEPIC Regulators
Isolated and Nonisolated High-Brightness LED
Power Supplies
Industrial Power Conversion
图1. MAX17499功能方框图
图2. MAX17499可编输入起动电压非隔离电源电路图
图3. MAX17499次级调整的绝缘电源电路图
图4. MAX17499初级调整双输出绝缘的通信电源电路图
图5. MAX17499 12-15V输出升压稳压电源电路图
图6. MAX17499典型应用电路图
The MAX17499/MAX17500 current-mode PWM controllers contain all the control circuitry required for the design of wide-input-voltage isolated and nonisolated power supplies. The MAX17499 is w EL l suited for low input voltage (9.5V DC to 24V DC) power supplies. The MAX17500 is well suited for universal input (rectified 85V AC to 265V AC) or telecom (-36V DC to -72V DC) power supplies.
The ICs contain an internal error amplifier that regulates the tertiary winding output voltage that is used in primary-side-regulated isolated power supplies. Primary-side regulation eliminates the need for an optocoupler. An input undervoltage lockout (UVLO) is provided for programming the input-supply start voltage and to ensure proper operation during brownout conditions. An opendrain UVLO flag output, with 210μs internal delay,allows the sequencing of a secondary-side controller.
The input-supply start voltage is externally programmable with a voltage-divider.A UVLO/EN input is used to shut down the devices. Internal digital soft-start eliminates
output voltage overshoot.
The MAX17500 has an internal bootstrap UVLO with large hysteresis that requires a minimum 23.6V for startup. The MAX17499 does not have the internal bootstrap UVLO and can be biased directly from a minimum voltage of 9.5V.
The switching frequency for the ICs is programmable with an external resistor. The MAX17499A/MAX17500A provide a 50% maximum duty-cycle limit, while the MAX17499B/MAX17500B provide a 75% maximum duty-cycle limit. These devices are available in 10-pin μMAX packages and are rated for operation over the -40℃ to +85℃ temperature range.
MAX17499主要特性:
_ Current-Mode Control
_ Programmable Switching Frequency Up to 625kHz
_ Accurate UVLO Threshold (1%)
_ Open-Drain UVLO Flag Output with Internal Delay
_ 36V to 72V Telecom Voltage Range
_ Universal Offline Input Voltage Range Rectified 85V AC to 265V AC (MAX17500)
_ 9.5V to 24V Input (MAX17499)
_ Digital Soft-Start
_ Internal Bootstrap UVLO with Large Hysteresis (MAX17500)
_ Internal Error Amplifier with 1.5% Accurate Reference
_ 50μA (typ) Startup Supply Current
_ 50% Maximum Duty-Cycle Limit (MAX17499A/MAX17500A)
_ 75% Maximum Duty-Cycle Limit (MAX17499B/MAX17500B)
_ 60ns Cycle-by-Cycle Current-Limit Propagation Delay
_ Available in Tiny 10-Pin μMAX Packages
MAX17499应用:
1/2, 1/4, and 1/8 Brick Power Modules
High-Efficiency, Isolated Telecom Power
Supplies
Networking/Servers
Isolated Keep-Alive Power Supplies
12V Boost and SEPIC Regulators
Isolated and Nonisolated High-Brightness LED
Power Supplies
Industrial Power Conversion
图1. MAX17499功能方框图
图2. MAX17499可编输入起动电压非隔离电源电路图
图3. MAX17499次级调整的绝缘电源电路图
图4. MAX17499初级调整双输出绝缘的通信电源电路图
图5. MAX17499 12-15V输出升压稳压电源电路图
图6. MAX17499典型应用电路图
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