EVL6566B-65W-QR STMicroelectronics, EVL6566B-65W-QR Datasheet - Page 12

• 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

3.3
12/34
Functional checking
Minimum load operation
Even at minimum load the power supply is still capable of regulating the output voltages
within the specification tolerances, as indicated by the measurements in
efficiency is still high.
Table 5.
Future new regulations and voluntary agreements for consumer and information technology
equipment require that power supplies and adapters have high efficiency not only at nominal
or maximum load but also at minimum and light load. In these conditions most of the time
good efficiency is a difficult task to achieve, as it increases the complexity of control. By just
adding a few external components, the oscillator structure of the L6566B can very easily
implement a frequency foldback. Thus, the frequency reduction minimizes the switching
losses, improving the power supply efficiency when it is working with an input power in the
range of 1 to 30 W.
The L6566B switching frequency is set by the current flowing in a resistor connected
between the OSC pin and ground (R15). During light-load operation the COMP (pin#9) level
decreases and Q4 injects into R15 and OSC (pin #13) a current inversely proportional to the
COMP voltage. Because the voltage on pin OSC is constant (1 V), increasing Q4 current
provides for the decrease of the current supplied by the pin and, as a consequence, the
oscillator frequency. Thus, a frequency reduction proportional to the output load is easily
obtained.
Figure 6
that the switching frequency is lower than the value measured at full load and decreases
proportionally to the COMP pin level.
Voltage [V]
Efficiency =
Pout [W] =
Pin [W] =
11.97
1.78
4.89
3.40
and
Output voltage measurement at reduced load, without HDD
7
Vin = 115 Vac-60 Hz
show the waveforms at different input power consumption. It can be noted
Current [A]
73.57 %
0.05
0.03
2.52
3.43
0.2
0.3
Doc ID 14630 Rev 2
Deviation
-0.25%
-1.11%
-2.20%
3.03%
Voltage [V]
Efficiency =
Pout [W] =
Pin [W] =
11.99
1.79
4.89
3.40
Vin = 230 Vac-50 Hz
Current [A]
68.47%
0.05
0.03
2.53
3.69
0.2
0.3
Table
5. The
Deviation
-0.08%
-0.56%
-2.20%
3.03%
AN2749