L6565N STMicroelectronics, L6565N Datasheet - Page 7

• Manufacturer Part Number: L6565N
• Description: IC CTCLR PWM SMPS CM UVLO 8DIP
• Manufacturer: STMicroelectronics

Specifications of L6565N

• Mfg Application Notes: 25W Converter Using the L6565 AppNote 30 W Adapter with PWM L6565 Controller AppNote 80 W SMPS - L6565/ESBT STC04IE170HV AppNote L6565 Quasi-Resonant Controller AppNote L6565-Based Low Cost SMPS for TV AppNote SMPS for CRT Monitors with the L6565 AppNote STEVAL-TSP001V1 AppNote Wide Input Volt Range SMPS for Metering AppNote
• Output Isolation: Isolated
• Voltage - Input: 10.3 ~ 18 V
• Power (watts): 1W
• Operating Temperature: -40°C ~ 150°C
• Package / Case: 8-DIP (0.300", 7.62mm)
• Output Voltage: 7 V
• Output Current: +/- 700 mA
• Output Power: 1 W
• Input Voltage: 10.3 V to 18 V
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: Through Hole
• For Use With: 497-9051 - BOARD DEMO STC03DE220HV/ L6565497-8227 - BOARD EVAL L6565/STW3N150497-6427 - BOARD EVAL POE STHS4257A/L6565D497-6422 - BOARD EVAL BASED ON L6565497-6415 - BOARD EVAL L6565/STW4N150 BASED497-6414 - BOARD EVAL L6565 EU220V BASED497-6339 - BOARD EVAL SMPS L6565 3PHASE APP497-6255 - BOARD 6W 3PH SMPS METERING ESBT497-5680 - POWER SUPPLY FOR STB US-110V497-5679 - BOARD EVAL 3PHASE W/ESBT 100W
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-5795-5

L6565
APPLICATION INFORMATION
Quasi-resonant operation in offline flyback converters lies in synchronizing MOSFET's turn-on to the transform-
er's demagnetization. Detecting the resulting negative-going edge of the voltage across any winding of the
transformer can do this. The L6565 is provided with a dedicated pin that allows doing the job with a very simple
interface, just one resistor.
Variable frequency operation - as a result of different operating conditions in terms of input voltage and output
current - is inherent in such functionality. The system always works close to the boundary between DCM (Dis-
continuous Conduction Mode) and CCM (Continuous Conduction Mode) operation of the transformer. The op-
eration is then identical to that of the so-called self-oscillating or Ringing Choke Converter (RCC).
Detailed Device Description
Internal Supply Block (see fig. 12)
A linear voltage regulator supplied by V
(pin 8) generates an internal 7V rail used for supplying the entire IC,
cc
except for the gate driver that is supplied directly from Vcc. In addition, a bandgap circuit generates a precise
internal reference (2.5V±1% @ 25°C) used by the control loop to ensure a good regulation with primary feed-
back technique.
In figure 12 it is also shown the undervoltage lockout (UVLO) comparator with hysteresis used to enable the
chip as long as the Vcc voltage is high enough to ensure a reliable operation.
Figure 12. L6565 internal supply block
+V
in
Vcc
8
-
+
UVLO
LIN.
REF.
REG.
2.5V
7V bus
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