L6565DTR STMicroelectronics, L6565DTR Datasheet - Page 10

• Manufacturer Part Number: L6565DTR
• Description: IC CTCLR PWM SMPS CM UVLO 8SOIC
• Manufacturer: STMicroelectronics

Specifications of L6565DTR

• 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): 650mW
• Operating Temperature: -40°C ~ 150°C
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: SMD/SMT
• For Use With: 497-9051 - BOARD DEMO STC03DE220HV/ L6565497-8410 - BOARD EVAL STP12IE95F4497-8227 - 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: 497-4017-2; 497-4017-2; 497-4584-2; E-L6565DTR

L6565
It acts on the clamp level of the control voltage V
of the converter's input voltage sensed through a dedicated pin (#3, VFF): the higher the input voltage, the lower
the setpoint. This is illustrated in the diagram of figure 17a that shows the relationship between the voltage at
the pin VFF and V
The schematic in figure 17b shows also how the function is included in the control loop. With a proper selection
of the external divider R1-R2 it is possible to achieve the optimum compensation described by the lower curve
in the diagram of figure 16.
In applications where this function is not wanted, e.g. because of a narrow input voltage range, the VFF pin can
be simply grounded, thus saving the resistor divider. The overcurrent setpoint will be then fixed at the maximum
value of about 1.4V (1.5V max.).
Line Feedforward is also beneficial to other characteristics of quasi-resonant converters: it improves their input
ripple rejection ability and limits the variation of the power stage's small-signal gain versus the line voltage.
Figure 17. a) Overcurrent setpoint vs. VFF voltage; b) Line Feedforward function block
10/17
INV
1
2.5V
csx
+
-
(with the error amplifier saturated high in the attempt of keeping output voltage regulation).
E/A
COMP
V
1.5
0.5
csx
+Vin
2
0
1
0
[V]
R1
R2
3
0.5
VFF
FORWARD
VOLTAGE
FEED
1
2 V
CS
4
csx
1.5
V
b)
, that is on the overcurrent setpoint, so that it is a function
+
+
Hiccup
VFF
-
-
PWM
ZCD
5
ZCD
V
[V]
COMP
2
STARTER
= Upper clamp
2.5
DISABLE
(reset-dominant)
Rs
starter STOP
R
S
Q
3
DRIVER
L6565
3.5
a)
7
GD