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.
|Country:||Central African Republic|
|Published (Last):||6 February 2016|
|PDF File Size:||10.55 Mb|
|ePub File Size:||6.18 Mb|
|Price:||Free* [*Free Regsitration Required]|
Description The UC provides active-power factor correction for uc3854 datasheet systems that otherwise would draw non-sinusoidal current from sinusoidal power lines. To do this, the UC contains a voltage amplifier, an analog multiplier and divider, a current amplifier, and a fixed-frequency PWM.
This datazheet enables the line current to follow the line voltage as closely as possible. The high reference dxtasheet and high oscillator amplitude of the UC minimize noise sensitivity while fast PWM elements permit chopping frequencies above kHz.
This standard applies to equipment with rated powers higher than 75 W. To do this, the multiplier divides the line current by the square of the RMS value of the line voltage.
In the present example, this amplifier uc3854 datasheet a zero at about Hz, and a gain of about 18 dB thereafter. Customers should validate uc3854 datasheet test datasheeet design implementation uc3854 datasheet confirm system functionality. The uc3854 datasheet drop across the 0. 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. To do this, the UC contains a voltage amplifier, an analog multiplier and divider, a current uc3854 datasheet, and a fixed-frequency PWM.
The result was a power factor of 0. To reduce the burden on the circuitry uc3854 datasheet datassheet power to this device, the UC features low starting supply current.
At full load, this preregulator exhibits a power factor of 0. With SS open, the uc3854 datasheet voltage is typically 7.
The UC uses average current-mode control to accomplish fixed-frequency current control with stability and low distortion. The UC is used uc3854 datasheet single-phase and three-phase systems with line voltages that vary from 75 V to V uc3854 datasheet line frequencies across the Hz to Hz range.
The nF feedback capacitor places a Hz pole uc3854 datasheet the voltage loop that prevents Hz ripple from propagating to the input current. The circuit of Figure 9 uc384 a typical uc3854 datasheet of the UC as a preregulator with datahseet power factor and efficiency.
This signal is multiplied by the output of the voltage amplifier uc3854 datasheet the datashdet multiplier to generate a reference signal for the current control loop. This provides a means to shut down the gate in case of trouble, or to add a time delay at power up.
To reduce the burden on the circuitry that supplies power to this device, the UC features low starting supply current. The power section is a boost converter, with the inductor operating in continuous mode. The UC uses average current-mode control to accomplish fixed-frequency current control with stability and low distortion. This same circuit is used at higher power levels with minor modifications to the power stage.
Furthermore, the output voltage must be higher than the peak value of the highest uc3854 datasheet AC line voltage, and all components must be rated accordingly. The ENA input must reach 2. The following formulas are used to calculate these resistors: These devices are available packaged in pin plastic and uc3854 datasheet dual in-line packages, and a variety of surface-mount packages.
UC High Power Factor Preregulator |
The assembly consists of two distinct parts: For this design example, use the parameters listed in Table 1 as the input parameters. These devices are available packaged in pin plastic and ceramic dual in-line packages, and a variety of surface-mount packages. 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.
Average Current Mode Enable. Unlike peak current-mode, average current control accurately maintains sinusoidal line current without slope compensation and with minimal response to noise transients. The duty cycle of this output is simultaneously controlled by four separate inputs to the chip.
The high reference voltage and uc3854 datasheet oscillator amplitude of the UC minimize noise sensitivity while fast PWM elements permit chopping frequencies above uc3854 datasheet. In this circuit, the voltage amplifier operates with a constant low-frequency gain for minimum output excursions.
Control Boost PWM to 0. The values shown in Figure 9 are for uc3854 datasheet output voltage of V Uc3854 datasheet. Operating Supply Max V. Additional controls of an auxiliary nature are provided. The voltage applied to VRMS, uc3854 datasheet 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.
A hysteresis gap of mV is provided at uc354 terminal to prevent uc3854 datasheet operation. The current-sense amplifier also operates with uc3854 datasheet low-frequency gain, but unlike the voltage amplifier, it is set up to give the current-control loop a very wide bandwidth.
This is done using line feedforward, which keeps the input power constant with varying input voltage assuming constant load power.