UC3852NG4

TEXAS INSTRUMENTS  UC3852NG4  芯片, 功率因子前置稳压器

The is a high Power Factor Preregulator provides active power-factor correction for systems that would otherwise draw high peak current pulses from AC power lines. This circuit implements zero-current switched boost conversion, producing sinusoidal input currents with a minimum of external components, while keeping peak current substantially below that of fully-discontinuous converters. It provides controlled switch on-time to regulate the output bulk DC voltage, an off-time defined by the boost inductor and a zero-current sensing circuit to reactivate the switch cycle. Even though switching frequency varies with both load and instantaneous line voltage, it can be maintained within a reasonable range to minimize noise generation. While allowing higher peak switch currents than continuous PFCs such as the pre-regulator, this device offers less external circuitry and smaller inductors, yet better performance and easier line-noise filtering than discontinuous current PFCs.

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>0.99 Power factor

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Few external parts required

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Controlled on-time boost PWM

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Zero-current switching

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Limited peak current

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Minimum and maximum frequency limits

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<1mA Starting current

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High-current FET drive output

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Under-voltage lockout

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Green product and no Sb/Br