L6566BH View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'L6566BH' PDF : 51 Pages View PDF
Application information
L6566BH
is allowed to reach 2 Vbe over 5 V, the L6566BH is latched off. See Section 5.9: Latched
disable function for more details on IC behavior under these conditions. If the impedance
externally connected to pin 15 is so low that the 5+2 VBE threshold cannot be reached or if
some means is provided to prevent that, the device is able to restart after the Vcc has
dropped below 5 V. Refer to Section 6: Application examples and ideas (Table 7) for
additional information.
Figure 22. OVP function: internal block diagram
PWM latch
RQ
SQ
to triggering
block
ZCD
11
5V
40kW
-
+
5pF
COUT
L6566BH
Monos table
M1
2 µs
Monostable STROBE
M2
0.5 µs
OVP
FF
R Q1
S
2-bit
counter
Fault
Counter
res et
AM11498v1
The ZCD pin is connected to the auxiliary winding through a resistor divider RZ1, RZ2 (see
Figure 8). The divider ratio kOVP = RZ2 / (RZ1 + RZ2) is chosen equal to:
Equation 13
k OVP
=
5
Vout OVP
Ns
Naux
where VoutOVP is the output voltage value that is to activate the protection, Ns the turn
number of the secondary winding, and Naux the turn number of the auxiliary winding.
34/51
Doc ID 16610 Rev 2
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