EVL6566B-65W-QR STMicroelectronics, EVL6566B-65W-QR Datasheet - Page 13

• Manufacturer Part Number: EVL6566B-65W-QR
• Description: BOARD EVAL SMPS FOR L6566B
• Manufacturer: STMicroelectronics
• Type: Power Factor Correctionr

Specifications of EVL6566B-65W-QR

• Main Purpose: AC/DC, Primary Side
• Outputs And Type: 1, Isolated
• Power - Output: 65W
• Voltage - Output: 700V
• Voltage - Input: 8 ~ 23 V
• Regulator Topology: Flyback
• Frequency - Switching: 100kHz
• Board Type: Fully Populated
• Utilized Ic / Part: L6566B
• Input Voltage: 90 V to 265 V
• Output Voltage: 1.8 V to 12 V
• Board Size: 150 mm x 75 mm
• Product: Power Management Modules
• Dimensions: 150 mm x 75 mm
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption
• Current - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: L6566B
• Other names: 497-10165

AN2749
Figure 6.
CH1: Vdrain
CH2: L6566B VGate
CH3: L6566B VComp
If the load is further decreased, the L6566B works in burst mode. Once the COMP (pin#9)
voltage drops below the internal threshold, the L6566B stops the gate driver operation
decreasing the internal circuitry consumption to minimize C19 discharging. Once the comp
voltage rises above the internal burst mode threshold the device restarts switching. In
Figure 8
because at no-load condition the auxiliary voltage powering the L6566B falls at input mains
increasing. This very often causes the supply voltage Vcc of the control IC to drop below the
UVLO threshold so that the operation becomes intermittent, which is undesired.
Furthermore, this must be traded off against the need of generating a voltage not exceeding
the maximum allowed by the control IC at full load to avoid overstress to the internal Vcc pin
clamping circuitry and consequent overheating of the controller.
To overcome this problem, the device, besides reducing its own consumption during burst-
mode operation, also features a proprietary adaptive UVLO function. It consists of shifting
the UVLO threshold downwards at light load, namely when the voltage at pin COMP falls
below a threshold VCOMPO internally fixed, so as to have a greater margin. To prevent any
malfunction during transients from minimum to maximum load the normal (higher) UVLO
threshold is re-established when the voltage at pin COMP exceeds VCOMPL and Vcc has
exceeded the normal UVLO threshold. The normal UVLO threshold ensures that at full load
the MOSFET is driven with a proper gate-to-source voltage. As visible in
measured showing that there is a good margin with respect to the maximum turnoff
threshold (8 V maximum) of the L6566B.
EVL6566B-40WSTB waveforms at
230 V - Pin=30 W
and
9
the burst-mode waveforms are shown. The pictures are taken at 265 V
Doc ID 14630 Rev 2
Figure 7.
CH1: Vdrain
CH2: L6566B VGate
CH3: L6566B VComp
EVL6566B-40WSTB waveforms at
230 V - Pin=4 W
Functional checking
Figure 9
the Vcc is
13/34