The uc3858 is a high-performance stand-alone power factor correction (PF) controller that is primarily used for power factor correction functions in AC\/DC converters. The pin functions of the
UC3858 are described as follows:
1. VFB: Feedback voltage input pin, used to receive feedback signals and compare the set output voltage.
2. COMP: Small signal voltage compensation pin, used to control the dynamic response of the circuit.
3. OCSET: Output current limit setting pin, used to adjust the output current limit threshold.
4. ZCD: zero current detection pin, used to detect the zero current point of AC power supply.
5. SENSE HI: high end of current sensor pin, connected to high end of current sensor.
6. SENSE LO: The low end of the current sensor pin, connected to the low end of the current sensor.
7. VFB\/COMP HI: High end of feedback voltage input\/small signal voltage compensation pin.
8. VFB\/COMP LO: Low end of feedback voltage input\/small signal voltage compensation pin.
9. VSENSE HI: high end of voltage sensor pin, connected to high end of voltage sensor.
10. VSENSE LO: low end of voltage sensor pin, connected to low end of voltage sensor.
11. GROUND: Ground pin, connected to the circuit ground.
In addition to the above pin functions, the UC3858 chip also contains other pins, such as VIN, UVLO, etc., which are used to connect external power supplies and provide other control functions. For detailed pin function descriptions, refer to the data manual of the UC3858.
The UC3858 is a professional phase-shifted controller chip commonly used in power factor correction (PFC) and flyback DC-DC converters. The following is the pin function description of the UC3858:
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Pin 1 (VDD) : The power supply voltage input pin is used to provide operating voltage to the chip.
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Pin 2 (VSS) : Power source.
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Pin 3 (COUT) : Clock output pin that outputs the frequency of the internal oscillator.
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Pin 4 (CP) : The non-reverse input pin of the error amplifier is used to adjust the amplitude and shape of the output waveform.
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Pin 5 (VREF) : Reference voltage used to generate an internal 5V power supply.
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Pin 6 (VSENSE) : Voltage sensing pin used to detect the input voltage.
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Pin 7 (CS) : Current sensing pin for detecting inductive current.
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Pin 8 (COUT) : Clock input pin that inputs the frequency of the external oscillator.
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Pin 9 (VSS) : Power source.
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Pin 10 (VDD) : The power supply voltage input pin is used to provide operating voltage to the chip.
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Please note that the pin function may vary depending on the application and circuit design. During the design process, be sure to refer to the chip data sheet and related circuit diagrams for accurate information.
2UCC3858 electrical parameters and limit values
1. Maximum use limit value
(1) Power supply voltage VDD18V;
(2) Grid drive current continuous value 0? 2A, pulse value 0.5A;
(3) Input current IAC200mA;
(4) Power consumption 1W;
(5) Storage temperature -65℃ ~ +150℃;
(6) Junction temperature -55℃ ~ +150℃;
(7) Pin temperature (10s welding) +300℃;
(8) The maximum forced voltage of the analog input is -0.3V ~ 11V.
2. Electrical parameters of UCC3858
Unless otherwise stated, UCC3858 is generally used at TA=0 ° C ~ 70 ° C, and has:
IIAC=100μA,TA=TJ。