CM6565 Datasheet, PDF (10/19 Pages) Champion Microelectronic Corp. – Noise Free 16 pin Self-Start Interleaved PFC with 180 Degree Phase Shift CRM PFC Controller for 90+/85+

CM6565
Noise Free 16 pin Self-Start Interleaved PFC with
180 Degree Phase Shift CRM PFC Controller for 90+/85+
Interleaved PFC:
CM6565 is the industry first interleaved PFC. The patented interleaved PFC idea was starting around mid 90. The
idea was to solve Qrr of 600V Boost diode at CCM. DCM boost does not have the Qrr issues, but DCM boost has
much higher ripple current and it increases switching loss and it causes the troubles of EMI circuits. The interleaved
PFC, it solves both ends. In the front end, two DCM boost converter currents combine together and it behaves like a
CCM with two times the frequency. From the lab data, its efficiency can be above 95% at full load without ultra fast
diodes.
CRM interleaved PFC can improve the efficiency of PFC further. CRM is ZCS at on time. By delaying the ZCD pin, it
can get about ZVS switching.
The 180 degree phase shift is done by the internal timer. The PFCOUT (master) is the clock of the timer. The slave
PFC does not have to sense any signal if the external boost inductor is matched well. Usually, the PFC sensing
resistor value at Isense Slave (pin 9) can use less than the resistor value of the Isense Master (pin 8) PFC sensing
resistor. It improves a bit of the efficiency.
To make PFC master and PFC slave components matched is important because it can reduce the power device
cost. Also, the matched components can be ensured both master and slave PFCs work at CRM mode. Without the
good matches, both PFC power device margin needs to over design to cover the worst mismatched condition.
Basically, it is like two 6561s work together with 180 degree phase shift + light load improvements.
Constant Power and Constant Bandwidth PFC:
The Gain Modulator with Vrms2, it keeps the power constant over universal line input. The Vrms1 and Vrms2 are
derived from IAC current. By deriving Vrms1 from IAC, it improves the light load efficiency and it reduces the circuit
and part counts. The product of Gain Modulator output current and Rmul determines the sine wave current and the
maximum value is about 500mV.
Boost Light Load Efficiency:
CM6565 is designed for both 90+ systems or 85+ systems.
For 90+ systems, CM6565 interleaved CRM PFC is ready to interface with CM6900 which is a secondary SRC+SR
controller or it can be interfaced with CM6901 which is a secondary LLC+SR controller. At light load, CM6565 will
drop the PFC bulk voltage from 380V to 342V and the slave PFC will be disabled. Only the master PFC is on during
the light load condition.
Boost Light Load Functions can be disabled by clamping pin 6 (SS) below 5V.
2008/10/09 Rev1.0
Champion Microelectronic Corporation
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