Data Sheet

FAN7529 Critical Conduction Mode PFC Controller

FAN7529 Rev. 1.0.2 13

4. Over-Current Protection Block

The MOSFET current is sensed using an external sens-

ing resistor for the over-current protection. If the CS pin

voltage is higher than 0.8V, the over-current protection

comparator generates a protection signal. An internal RC

filter is included to filter switching noise.

Figure 36. Over-Current Protection Block

5. Switch Drive Block

The FAN7529 contains a single totem-pole output stage

designed for direct drive of the power MOSFET. The

drive output is capable of up to +500/-800mA peak cur-

rent with a typical rise and fall time of 50ns with 1nF load.

The output voltage is clamped to 13V to protect the

MOSFET gate if the V

voltage is higher than 13V.

6. Under-Voltage Lockout Block

If the V

voltage reaches 12V, the IC’s internal blocks

are enabled and start operation. If the V

voltage drops

below 8.5V, most of the internal blocks are disabled to

reduce the operating current. V

voltage should be

higher than 8.5V under normal conditions.

8pF

40k

Over Current Protection

Comparator

0.8V

OCP

Signal

FAN7529 Rev. 00