MP44010 – BOUNDARY MODE PFC CONTROLLER

MP44010 Rev. 1.11

www.MonolithicPower.com

11

10/17/2012

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

© 2012 MPS. All Rights Reserved.

Layout Guide

For boundary mode PFC operation, the output is

fed back to FB pin and is compared with the

reference voltage. So a constant reference

voltage is very important for output voltage

accuracy. Therefore, the wire from FB pin to the

feedback resistors should be as short as possible.

The envelope of the inductor current is from the

multiplier output which is generated by rectified

AC voltage. Therefore a good layout should keep

MULT pin immune to noise. It is recommended

that placing a small ceramic cap from MULT pin

to GND.

For zero current sensing, R5 should be placed

close to ZCS and a long connection wire should

be avoided. If the long wire is necessary, a small

bypass cap is needed to avoid noise.

For inductor current sensing, although there is

on-chip filter on CS pin, it is still recommended

that the wire from current sensing resistor to CS

pin should be as short as possible to prevent

falsely turning off MOSFET. If it is difficult to

achieve using short wire, an external filter from

sensing resistor to CS pin is recommended.

To keep the chip operating with a stable VIN

voltage, a big E-cap and a small ceramic cap are

good combination as VIN caps. In addition, the

VIN caps should be close to VIN pin to prevent

VIN voltage fluctuation.

Please see the MP44010 demo board for

recommended layout.

Design Example

Case 1:

Below is a design example following the

application guideline for the specifications:

85~265V

400V

100W

The detailed application schematic is shown in

Figure 6. The typical performance and circuit

waveforms have been shown in the Typical

Performance Characteristics section. For more

possible applications of this device, please refer

to related Evaluation Board Datasheets.

Figure 6—100W MP44010 Design Example