L6564HTR STMicroelectronics, L6564HTR Datasheet - Page 27

• Manufacturer Part Number: L6564HTR
• Description: Power Factor Correction ICs High Volt Start Up 700V PFC 100uA 6mA
• Manufacturer: STMicroelectronics

Specifications of L6564HTR

• Product Category: Power Factor Correction ICs
• Rohs: yes
• Maximum Power Dissipation: 0.75 W
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: SO-14
• Minimum Operating Temperature: - 25 C

L6564H
As the V
operating and the HV generator is cut off by the V
powered by the energy stored in the V
that it is made with an auxiliary winding in the transformer of the cascaded DC-DC converter
and a steering diode) develops a voltage high enough to sustain the operation. The residual
consumption of this circuit is just the one on the 15 MΩ resistor (≈ 10 mW at 400 Vdc),
typically 50-70 times lower, under the same conditions, as compared to a standard startup
circuit made with external dropping resistors.
At converter power-down the DC-DC converter loses regulation as soon as the input voltage
is so low that either peak current or maximum duty cycle limitation is tripped. V
and stop IC activity as it falls below the UVLO threshold (9.5 V typ.). The V
de-asserted as the V
HV generator can now restart. However, if Vin < V
HV generator is disabled. This prevents converter restart attempts and ensures monotonic
output voltage decay at power-down in systems where brownout protection (see
Section 6.6: Power management/housekeeping functions
If the device detects a fault due to feedback failure, the internal V
over the V
pin oscillates between its turn-on and turn-off thresholds until the HV bus is recycled and
drops below the startup threshold of the HV generator.
The high voltage startup circuitry is capable of guaranteeing a safe behavior in case of
short-circuit present on the DC-DC output when the V
by the same auxiliary inding.
the associated power transfer. At short-circuit the auxiliary circuit is no longer able to sustain
the V
consumption and drops more until the V
startup generator restarts and when the V
starts switching. In this manner the power is transferred from mains to PFC output only
during a short time for each trep cycle.
Figure 40. High voltage startup behavior during latch-off protection
CC
HV_EN
which starts dropping; reaching its V
CC
Vcc
(pin 13)
(pin 14)
Vcc
V
Vcc
CC
Vcc
GD
HVstart
restart
Vin
OFF
voltage reaches the startup threshold (12 V typ.) the low voltage chip starts
ON
Off
(turn-off threshold). As a result, shown in
CC
Fault occurs here
voltage goes below a threshold V
HV generator is turned on
Figure 41
Doc ID 022960 Rev 2
CC
shows how the PFC manages the V
CCrestart
Disable latch is reset here
capacitor until the self-supply circuit (we assume
CC
CC
again crosses its turn-on threshold the IC
Off
threshold is tripped. Now, the high voltage
CC
HVstart
threshold the IC stops switching, reduces
Input source is removed here
_OK signal asserted high. The device is
HV generator turn-on is disabled here
CC
, HV_EN is de-asserted too and the
Figure 40
of both controllers are generated
) is not used.
CCrestart
High voltage startup generator
CCrestart
located at about 6 V. The
, the voltage at the V
is brought up to
CC
CC
_OK signal is
CC
cycling and
then drops
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CC