L6564 STMicroelectronics, L6564 Datasheet - Page 7

• Manufacturer Part Number: L6564
• Description: 10 pin transition-mode PFC controller
• Manufacturer: STMicroelectronics

L6564
3
Table 3.
n°
1
2
3
4
5
COMP
Name
MULT
VFF
INV
CS
Pin connection
Figure 2.
Pin description
Inverting input of the error amplifier. The information on the output voltage of the PFC pre-
regulator is fed into the pin through a resistor divider.
The pin normally features high impedance.
Output of the error amplifier. A compensation network is placed between this pin and INV (pin
1) to achieve stability of the voltage control loop and ensure high power factor and low THD.
To avoid uncontrolled rise of the output voltage at zero load, when the voltage on the pin falls
below 2.4 V the gate driver output will be inhibited (burst-mode operation).
Main input to the multiplier. This pin is connected to the rectified mains voltage via a resistor
divider and provides the sinusoidal reference to the current loop. The voltage on this pin is used
also to derive the information on the RMS mains voltage.
Input to the PWM comparator. The current flowing in the MOSFET is sensed through a resistor,
the resulting voltage is applied to this pin and compared with an internal reference to determine
MOSFET’s turn-off.
A second comparison level at 1.7V detects abnormal currents (e.g. due to boost inductor
saturation) and, on this occurrence, activates a safety procedure that temporarily stops the
converter and limits the stress of the power components.
Second input to the multiplier for 1/V
connected from the pin to GND. They complete the internal peak-holding circuit that derives the
information on the RMS mains voltage. The voltage at this pin, a dc level equal to the peak
voltage on pin MULT (3), compensates the control loop gain dependence on the mains voltage.
Never connect the pin directly to GND but with a resistor ranging from 100K ohm (minimum) to
2M ohm (maximum). This pin is internally connected to a comparator in order to provide the
brownout (AC mains undervoltage) protection. A voltage below 0.8V shuts down (not latched)
the IC and brings its consumption to a considerably lower level. The IC restarts as the voltage
at the pin goes above 0.88V.
Pin connection
Doc ID 16202 Rev 4
2
function. A capacitor and a parallel resistor must be
Function
Pin connection
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