L6564HTR STMicroelectronics, L6564HTR Datasheet - Page 24

• 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

Application information
Figure 36. Effect of boost inductor saturation on the MOSFET current and detection method
6.6
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occasionally slightly saturate when the PFC stage is restarted because of a larger load
demand. This happens when the restart occurs at an unfavorable line voltage phase, i.e.
when the output voltage is significantly below the rectified peak voltage. As a result, in the
boost inductor, the inrush current coming from the bridge rectifier adds to the switched
current and, furthermore, there is little or no voltage available for demagnetization.
To cope with a saturated inductor, the L6564H is provided with a second comparator on the
current sense pin (CS, pin 4) that stops the IC if the voltage, normally limited within 1.1 V,
exceeds 1.7 V. After that, the IC attempts to restart through the internal starter circuitry; the
starter repetition time is twice the nominal value to guarantee lower stress for the inductor
and boost diode. Hence, system safety is considerably increased.
Power management/housekeeping functions
A communication line with the control IC of the cascaded DC-DC converter can be
established via the disable function included in the PFC_OK pin (see
details). This line is typically used to allow the PWM controller of the cascaded DC-DC
converter to shut down the L6564H in case of light load and to minimize the no-load input
consumption. Should the residual consumption of the chip be an issue, it is also possible to
cut down the supply voltage. Interface circuits are shown in
operation assumes that the cascaded DC-DC converter stage works as the master and the
PFC stage as the slave or, in other words, that the DC-DC stage starts first, it powers both
controllers and enables/disables the operation of the PFC stage.
Doc ID 022960 Rev 2
Figure 37
. Needless to say, this
Section 6.2
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AM11462v1
L6564H