UC2843B

高性能电流模式控制器 High Performance Current Mode Controllers

The UC3842B, UC3843B series are high performance fixed frequency current mode controllers. They are specifically designed for Off-Line and dc-to-dc converter applications offering the designer a cost-effective solution with minimal external components. These integrated circuits feature a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator, and a high current totem pole output ideally suited for driving a power MOSFET. Also included are protective features consisting of input and reference undervoltage lockouts each with hysteresis, cycle-by-cycle current limiting, programmable output deadtime, and a latch for single pulse metering. These devices are available in an 8-pin dual-in-line and surface mount SO-8 plastic package as well as the 14-pin plastic surface mount SO-14. The SO-14 package has separate power and ground pins for the totem pole output stage. The UCX842B has UVLO thresholds of 16 V on and 10 V off, ideally suited for off-line converters. The UCX843B is tailored for lower voltage applications having UVLO thresholds of 8.5 V on and 7.6 V off.

Features

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Trimmed Oscillator for Precise Frequency Control

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Oscillator Frequency Guaranteed at 250 kHz

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Current Mode Operation to 500 kHz

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Automatic Feed Forward Compensation

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Latching PWM for Cycle-By-Cycle Current Limiting

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Internally Trimmed Reference with Undervoltage Lockout

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High Current Totem Pole Output

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Undervoltage Lockout with Hysteresis

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Low Startup and Operating Current

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Pb-Free Packages are Available