The UC provides active power factor correction for power sys- tems that otherwise would draw non-sinusoidal current from sinusoi- dal power lines. The UCA/B products are pin compatible enhanced versions of the UC Like the. UC, these products provide all of the functions necessary for. UC datasheet, UC circuit, UC data sheet: TI – High Power Factor Preregulator,alldatasheet, datasheet, Datasheet search site for Electronic.
|Published (Last):||23 March 2013|
|PDF File Size:||4.18 Mb|
|ePub File Size:||10.14 Mb|
|Price:||Free* [*Free Regsitration Required]|
To reduce the burden on the circuitry that supplies power to this device, uc3854 datasheet UC features low starting supply current. This device implements all the control functions necessary to build a power supply capable of optimally using available power-line current while minimizing line-current distortion. These devices are available packaged in pin plastic uc3854 datasheet ceramic dual in-line packages, and a variety of surface-mount packages.
The UC is used in single-phase and three-phase systems with line voltages that vary from 75 V to V and line frequencies across the Hz to Hz range. The UC uses average current-mode control to accomplish fixed-frequency current control with stability and low distortion.
The UC is used in single-phase and three-phase systems with line voltages that vary from 75 V to V and line frequencies across the Hz to Hz range.
Unlike peak current-mode, average current control accurately maintains sinusoidal line current uc3854 datasheet slope compensation and with minimal response to noise transients. Additional controls of an auxiliary uc3854 datasheet are provided. The high reference voltage and high oscillator amplitude of the UC minimize noise sensitivity while fast PWM elements permit chopping frequencies above kHz.
Description The UC provides active-power factor correction for power systems that otherwise would draw non-sinusoidal current from sinusoidal power lines.
To reduce the burden on the circuitry that supplies uc3854 datasheet to this device, the UC features low starting supply current. The following formulas are used to calculate these resistors:.
This device implements uc3854 datasheet the control functions necessary to build a power supply capable of optimally using available power-line current while minimizing line-current distortion. The values shown in Figure 9 are for an output voltage of V DC.
The UC uses average current-mode control to accomplish fixed-frequency current control with stability and low distortion. U3c854 nF feedback capacitor places a Hz pole in the voltage loop uc3854 datasheet prevents Hz ripple from propagating to the input current.
To do uc3854 datasheet, the UC contains a voltage amplifier, an analog multiplier and divider, a current amplifier, and a fixed-frequency PWM.
UC Datasheet(PDF) – Texas Instruments
These devices are available packaged uc3854 datasheet pin plastic and ceramic dual in-line packages, and a variety of surface-mount packages. This is done using line feedforward, which keeps the input power constant with varying input voltage assuming constant load power.
To force the line current waveshape to follow the line voltage, a sample of the power line voltage in waveform is introduced at IAC. To do this, the multiplier divides the line current by the square of the RMS value of the line uc3854 datasheet.
The following uc3854 datasheet are used to calculate these resistors: The power section is a boost converter, with the uc3854 datasheet operating fatasheet continuous mode. The voltage applied to VRMS, proportional to the average of the rectified line voltage and proportional to the RMS value, is squared in the UC, and then used as a divisor by the multiplier block.
This bandwidth enables the line current to follow the line voltage as closely as possible. Undervoltage protection is provided directly at VCC, where the on and off thresholds are 16 V and 10 V.
High Power Factor Preregulator
Average Current Mode Enable. The current-sense amplifier also operates with high low-frequency gain, but unlike the voltage amplifier, it is set uc3854 datasheet to give the current-control loop a very wide bandwidth. Furthermore, the output voltage uc3854 datasheet be higher than the peak value of the highest expected Dstasheet line voltage, and all components must be rated accordingly.
Unlike peak current-mode, average current uc3854 datasheet accurately maintains sinusoidal line current without slope compensation and with minimal response to noise transients.
The ENA input must reach 2. This standard applies to equipment with rated powers higher than 75 W. Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. In this circuit, the voltage uc3854 datasheet operates with a constant low-frequency gain for minimum output excursions. A hysteresis gap of mV is provided at this terminal uc3854 datasheet prevent erratic operation.
At full load, this preregulator exhibits a power factor of 0. The duty cycle uc3854 datasheet this output is simultaneously controlled by four separate inputs to datashewt chip. The circuit of Figure 9 shows a uc3854 datasheet application of the UC as a darasheet with high power factor and efficiency. The voltage at SS pin reduces the reference voltage used by the error amplifier to regulate the output DC voltage.
In the present example, this amplifier has a zero at about Hz, and a gain of about 18 dB thereafter. In this mode, the duty cycle is dependent on the ratio between input and output voltages; also, the input current has low switching-frequency ripple, which means that the line noise is low.
Control Boost PWM to 0. This same circuit is used at higher power levels with minor modifications to the uc3854 datasheet stage. With SS open, the uc3854 datasheet voltage is typically 7.