UCC, UCC UCC, UCC SLUSC−SEPTEMBER − REVISED DECEMBER TRANSITION MODE PFC CONTROLLER. 1 . UCCP IC PFC CTLR TRANS-MODE 8-DIP Texas Instruments datasheet pdf data sheet FREE from Datasheet (data sheet) search for. Details, datasheet, quote on part number: UCC Part family, UCC PFC Controller for low to medium power applications requiring compliance with.

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This prevents the output dc voltage from going above 7. This pin is the input for the zero 2805 detect comparator. Additionally, pulling this pin below the 2851 threshold turns off the output switching, ensuring that the gate drive is held off while the boost output is pre-charging and also ensuring no runaway if feedback path is open.

Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. An external gate drive resistor may be needed to limit the peak current depending on the VCC voltage being used. The bias voltage should also be clamped with an external zener diode to a maximum of 18 V.

It is important to choose a device that minimizes gate charge and capacitance and minimizes the sum of switching and conduction losses at a given frequency. Loop compensation components are connected between this pin and ground. The clamp has the sink and source capability of 10 mA. This drawing is subject to change without notice.

This translates to a minimum switching frequency of 5 kHz. RS2 and RS3 can be added for further scaling.

IC datasheet pdf-ucc,pdf datasheet (TRANSITION MODE PFC CONTROLLER)_百度文库

As shown in Figure 1, the switch current is compared to the reference signal output of the multiplier directly. Maximum Current Sense Threshold? UCCDR to order quantities of 2, devices per reel. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.


Not recommended for new designs. The UCC is suitable for multiple applications including AC adapters where a two-stage power conversion is needed.

Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. TI assumes no liability for applications assistance or customer product design.

In other words, the boost inductor value should be chosen for switching frequencies greater than 5 kHz. UCC employs a transconductance amplifier gM amp with gain scheduling for improved transient response refer to Figure The UCC is suitable for applications such as electronic ballasts dafasheet there is no down-stream PWM conversion and the advantages of smaller VCC capacitor and improved transient response can be realized.

The CS pin already has an internal filter for noise due to switching transients. An internal rail of 7. Body dimensions do not include mold flash or protrusion, 20851 to exceed 0. The rising edge threshold of the ZCD comparator can be as high as 2. The low start-up and operating currents of the device results in low power consumption and ease of start-up. Integral type control at low frequencies is preferred here because the loop gain varies considerably with line conditions.

Texas Instruments

This voltage is one of the inputs to the multiplier, with a dynamic input range of 2. Highly accurate internal bandgap reference leads to tight regulation of output voltage in normal and OVP conditions, resulting in higher system reliability.

Transition Mode Control The boost converter, the most common topology used for power factor correction, can operate in two modes — continuous conduction code CCM and discontinuous conduction mode DCM. The bias capacitor must be large enough to maintain sufficient voltage with ac line variations. The slew rate enhancement circuitry of the gM amplifier that is activated during overvoltage conditions slews the COMP pin to about 2.

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In addition, an external R-C filter may be required to suppress the noise spikes. The gate drive output for an external boost switch.

All linear dimensions are in inches millimeters. Reference Design Board Layout www.

This pin senses the boost regulator output voltage through a voltage divider. This ensures that the zero power comparator is not activated during transient behavior when the slew rate enhancement circuitry is enhanced. The multiplier output is approximately 0. The filtering requirement is not severe and 280551 is not a disadvantage.

Keep in mind that the low corner frequency of this filter may compromise the overall power factor. An internal clamp on the multiplier output terminates the switching cycle if this pin voltage exceeds datashheet. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in such safety-critical applications. Be sure to connect a 0.

Datasheet, PDF – Alldatasheet

TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. The internal active clamp circuitry prevents the voltage from going to a negative or a high positive value.

Efforts are underway to better integrate information from third parties. Output of the transconductance error amplifier.