L6564D STMicroelectronics, L6564D Datasheet - Page 18

• Manufacturer Part Number: L6564D
• Description: IC PFC CTRLR TRANSITION 10SSOP
• Manufacturer: STMicroelectronics

Specifications of L6564D

• Mode: Discontinuous (Transition)
• Frequency - Switching: 1MHz
• Current - Startup: 90µA
• Voltage - Supply: 10.3 V ~ 22.5 V
• Operating Temperature: -25°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 10-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: L6564; L6564

Application information
6
6.1
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Application information
Overvoltage protection
Normally, the voltage control loop keeps the output voltage Vo of the PFC pre-regulator
close to its nominal value, set by the ratio of the resistors R1 and R2 of the output divider. A
pin of the device (PFC_OK) has been dedicated to monitor the output voltage with a
separate resistor divider (R3 high, R4 low, see
the voltage at the pin reaches 2.5 V if the output voltage exceeds a preset value, usually
larger than the maximum Vo that can be expected.
Example: V
51 kΩ.
When this function is triggered, the gate drive activity is immediately stopped until the
voltage on the pin PFC_OK drops below 2.4 V. Notice that R1, R2, R3 and R4 can be
selected without any constraints. The unique criterion is that both dividers have to sink a
current from the output bus which needs to be significantly higher than the bias current of
both INV and PFC_OK pins.
Figure 27. Output voltage setting, OVP and FFP functions: internal block diagram
O
= 400 V, V
OX
= 434 V. Select: R3 = 8.8 MΩ; then: R4 = 8.8 MΩ ·2.5/(434-2.5) =
Doc ID 16202 Rev 2
Figure
27). This divider is selected so that
L6564