L6566B STMicroelectronics, L6566B Datasheet - Page 18

• Manufacturer Part Number: L6566B
• Description: IC CTRLR OVP OTP UVLO HV 16SOIC
• Manufacturer: STMicroelectronics

Specifications of L6566B

• Output Isolation: Isolated
• Frequency Range: 10 ~ 300kHz
• Voltage - Input: 8 ~ 23 V
• Power (watts): 750mW
• Operating Temperature: -40°C ~ 150°C
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Output Current: 800 mA
• Output Power: 750 mW
• Input Voltage: 8 V to 23 V
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: SMD/SMT
• Duty Cycle (max): 75 %
• Selectable Multi-mode Operation: fixed frequency or quasi-resonant
• For Use With: 497-6452 - BOARD EVAL FOR L6566B497-6451 - BOARD EVAL FOR L6566B497-6450 - BOARD EVAL FOR L6566B497-6449 - BOARD EVAL FOR L6566A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Application information
5.1
18/51
If FF operation is selected:
1.
Equation 1
2.
The L6566B is specifically designed for applications with no PFC front-end; pin 6 (FMOD)
features an auxiliary oscillator that can modulate the switching frequency (when FF
operation is selected) in order to mitigate EMI emissions by a spread-spectrum action.
High-voltage start-up generator
Figure 5
It is made up of a high-voltage N-channel FET, whose gate is biased by a 15 MΩ resistor,
with a temperature-compensated current generator connected to its source.
Figure 5.
FF mode from heavy to light load. The system operates exactly like a standard current
mode control, at a frequency f
both DCM and CCM transformer operation are possible, depending on whether the
power that it processes is greater or less than:
where Vin is the input voltage to the converter, V
regulated output voltage times the primary-to-secondary turn ratio) and Lp the
inductance of the primary winding. Pin
continuous to discontinuous operation mode of the transformer.
Burst-mode with no or very light load. This kind of operation is activated in the same
way and results in the same behavior as previously described for QR operation.
shows the internal schematic of the high-voltage start-up generator (HV generator).
High-voltage start-up generator: internal schematic
L6566B
Vcc_OK
sw
determined by the externally programmable oscillator:
Pin
15 M
T
T
CONTROL
=
is the power level that marks the transition from
HV_EN
⎛
⎜ ⎜
⎝
Vin
GND
3
Vin
f 2
sw
+
V
V
1
R
Lp
HV
R
R
I
charge
I
HV
the reflected voltage (i.e. the
⎞
⎟ ⎟
⎠
2
5
Vcc
L6566B