The following user guide supports the FAN9611/12 400W evaluation board for
interleaved boundary-conduction-mode power-factor-corrected supply. It should be used
in conjunction with the FAN9611/12 datasheet as well as the Fairchild application note
AN-6086 Design Considerations for Interleaved Boundary-Conduction Mode PFC Using
FAN9611 / FAN9612. Although marked FAN9612, the evaluation board can be
interchangeably used to evaluate either the FAN9611 (10V turn-on threshold) or
FAN9612 controller (12.5V turn-on threshold). Please visit Fairchild’s website at
www.fairchildsemi.com
for additional information.
1. Overview of the Evaluation Board
The FAN9611/12 interleaved dual Boundary-Conduction-Mode (BCM) Power-FactorCorrection (PFC) controllers operate two parallel-connected boost power trains 180º out
of phase. Interleaving extends the maximum practical power level of the control
technique from about 300W to greater than 800W. Unlike the continuous conduction
mode (CCM) technique often used at higher power levels, BCM offers inherent zerocurrent switching of the boost diodes (no reverse-recovery losses), which permits the use
of less expensive diodes without sacrificing efficiency. Furthermore, the input and output
filters can be smaller due to ripple current cancellation between the power trains and
doubling of effective switching frequency.
The advanced line feedforward with peak detection circuit minimizes the output voltage
variation during line transients. To guarantee stable operation with less switching loss at
light load, the maximum switching frequency is clamped at 525kHz. Synchronization is
maintained under all operating conditions.
Protection functions include output over-voltage, over-current, open-feedback, undervoltage lockout, brownout, and redundant latching over-voltage protection. The
FAN9611/12 is available in a lead-free 16-lead SOIC package.
This FAN9611/12 evaluation board is a four-layer board designed for 400W (400V/1A)
rated power. Thanks to the phase management, the efficiency is maintained above 96% at
low-line and high-line, even down to 10% of the rated output power. Efficiency is 96.4%
at line voltage 115V
Low Total Harmonic Distortion, High Power Factor
180° Out-of-Phase Synchronization
Automatic Phase Disable at Light Load
1.8A Sink, 1.0A Source, High-Current Gate Drivers
Transconductance (g
Voltage-Mode Control with (V
Closed-Loop Soft-Start with Programmable Soft-Start Time for Reduced Overshoot
Minimum Restart Timer Frequency to Avoid Audible Noise
Maximum Switching Frequency Clamp
Brownout Protection with Soft Recovery
Non-Latching OVP on FB Pin and Second-Level Latching Protection on OVP Pin
Open-Feedback Protection
Over-Current and Power-Limit Protection for Each Phase
Low Startup Current: 80µA Typical
Works with DC, 50Hz to 400Hz AC Inputs
This board has been designed and optimized for the following conditions:
Input Voltage Range Rated Output Power
VIN Nominal : 85~264VAC
V
Supply : 13VDC~18VDC
DD
Note:
1. Minimum output voltage during the 20ms hold-up time is 330VDC.
400W 400V-1A
Output Voltage
(Rated Current)
V
V
f
Efficiency > 96% down to 20% load (115V
Efficiency > 97% down to 20% load (230V
= 85~264VAC
LINE
= 400V
OUT
> 50kHz
SW
AC
AC
)
)
PF > 0.99 at full load
The trip points for the built-in protections are set as below in the evaluation board.
The non-latching output OVP trip point is set at 108% of the nominal output voltage.
The latching output OVP trip point is set at 117% of the nominal output voltage.
The line UVLO (brownout protection) trip point is set at 68V
(10VAC hysteresis).
AC
The pulse-by-pulse current limit for each MOSFET is set at 9.1A.
The maximum power limit is set at ~120% of the rated output power. The phase
management function permits phase shedding/adding ~15% of the nominal output power
for high line (230V
). This level can be programmed by modifying MOT resistor (R6).
Before testing the board; DC voltage supply for VDD, AC voltage supply for line input,
and DC electric load for output should be connected to the board properly.
1. Supply V
specification for V
for the control chip first. It should be higher than 13V (refer to the
DD
turn-on threshold voltage in Table 1).
DD
Table 1. Specification Excerpt from FAN9611/12 Datasheet
Symbol Parameter Conditions Min. Typ. Max. Unit
Supply
I
Startup Supply Current VDD = VON – 0.2V 80 110 µA
STARTUP
IDD Operating Current Output Not Switching 3.7 5.2 mA
I
Dynamic Operating Current fSW = 50kHz; C
DD_DYM
VON
V
OFF
V
HYS
UVLO Start Threshold, FAN9611
UVLO Start Threshold, FAN9612 12.0 12.5 13.0 V
UVLO Stop Threshold Voltage VDD Decreasing 7.0 7.5 8.0 V
UVLO Hysteresis, FAN9611
UVLO Hysteresis, FAN9612 5.0
VDD Increasing
V
– V
OFF
ON
= 2nF 4 6 mA
LOAD
9.5 10.0 10.5 V
2.5
V
V
2. Connect the AC voltage (85~265VAC) to start the FAN9611/12 evaluation board.
Since FAN9611/12 has brownout protection, any input voltages lower than operation
range triggers the protection.
3. Change load current (0~1A) and check the operation.