illustrate

The UCC2850x home provides all the control functions needed for a power factor correction preconditioner and an active second-stage DC-DC converter. The controller realizes that by shaping the AC input current waveform, it corresponds to the AC input line voltage, and uses the average current mode to control the power factor close to 1. The DC-DC converter uses a peak current control mode to perform step-down power conversion.

The PFC stage is advanced modulation, while the second stage is the minimum allowable synchronization increase of the trailing edge between overlap and PWM switching. This reduces the number of capacitors. In order ripple current large capacity output operation more than three to one) input line voltage, line feedforward (five FF is used to maintain a constant input supply voltage change.

characteristic

• Combined PFC and downstream converter control
• Controls the boost pre-regulator to the near power factor
• Precise power limits
• Improved feedforward line adjustment
• The peak current mode is controlled in the second stage
• Programmable oscillator
• Leading-Edge/Trailing-Edge modulation reduces output ripple
• Low starting current
• The second stage begins synchronous action with programmable soft start
• The second stage is programmable shutdown