EVL6566A-75WES4 STMicroelectronics, EVL6566A-75WES4 Datasheet - Page 20

• Manufacturer Part Number: EVL6566A-75WES4
• Description: BOARD DEMO FOR L6563/LL6566A
• Manufacturer: STMicroelectronics
• Type: Power Factor Correctionr

Specifications of EVL6566A-75WES4

• Main Purpose: AC/DC, Primary and Secondary Side with PFC
• Outputs And Type: 1, Isolated
• Power - Output: 75W
• Voltage - Output: 19V
• Current - Output: 4A
• Voltage - Input: 90 ~ 264VAC
• Regulator Topology: Flyback
• Board Type: Fully Populated
• Utilized Ic / Part: L6563, L6566A, TSM1014
• Input Voltage: 90 V to 264 V
• Output Voltage: 19 V
• Dimensions: 78 mm x 170 mm
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: L6563S, L6566A
• Other names: 497-8834

Functional check
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To restart the system the input power must be recycled.
The PFC_OK pin has two functions as a non-latched IC disable. A voltage below 0.2 V shuts
down the IC, reducing its consumption below 1.5 mA (typical). In this case both PWM_STOP
and PWM_LATCH keep their high impedance status. To restart the IC simply let the voltage
at the pin go above 0.3 V.
Note that this function offers a complete protection against not only feedback loop failures or
erroneous settings, but also against a failure of the protection itself. If either resistor of the
PFC_OK divider fails short or opens or the PFC_OK (#7) pin is floating, this results in
shutting down the L6563S and stopping the controller operation of the flyback stage.
The event of an open loop is given in
stopping the operation of the L6563S and the activation of the PWM_LATCH pin that is
connected to the L6566A pin #7 (DIS). This function of the L6566A is a latched device
shutdown. Internally the pin connects a comparator that, when the voltage on the pin
exceeds 4.5 V, shuts down the IC and brings its consumption to a value barely higher than
before startup. The internal L6566A logic opens also the pin Vcc_PFC, therefore the
L6563S remains inactive after latching because it is no longer powered.
This state is latched and the input power must be recycled in order to restart the IC. The
latch is removed as the voltage on the AC_OK goes below the brownout threshold.
The flyback stage is also protected against open loop conditions that lead to losing control
of the output voltage.
The L6566A OVP function monitors the voltage on the ZCD pin (#11) during the MOSFET's
off-time, during which the voltage generated by the auxiliary winding is proportional to the
converter's output voltage. If the voltage on the pin exceeds an internal 5 V reference, an
overvoltage condition is assumed and the device is shut down. An internal current generator
is activated that sources 1 mA out of the VFF pin (#15). If the VFF voltage is allowed to
reach 2 VBE over 5 V, the L6566A is latched off (
VCC starts decreasing until it reaches a value 0.5 V below the turn-on threshold. Then the
Figure 19. EVL6566-75WES4 PFC open loop at 115 Vac-60 Hz - full load
CH1: Drain voltage
CH2: PFC output voltage
Doc ID 15447 Rev 3
Figure 19
CH3: PFC_OK pin voltage
CH4: PWM_LATCH pin voltage
. We can notice the protection intervention
Figure 20
). As soon as the IC is latched,
AN2941