FA5550 Fuji Electric holdings CO.,Ltd, FA5550 Datasheet - Page 13

• Manufacturer Part Number: FA5550
• Description: Power Factor Correction Converter
• Manufacturer: Fuji Electric holdings CO.,Ltd

(8) No.8 pin (VCC pin)
Function:
(a) Power Supply to the IC
How to use:
(a) Power Supply to the IC
・ How to connect:
・ Operation
Rev.1 Feb-2008
Connect a starting resistor between the voltage line after
rectified and Vcc pin.
In general, connect voltage of the subsidiary coil attached to
transformer after rectifying and smoothing it.
Or, connect an external DC power source.
When the VCC voltage is supplied from the subsidiary coil, the
current running through the starting resistor is charged into the
smoothing capacitor at start-up, and the IC will start if the
voltage increases up to the UVLO on-threshold voltage.
The current of 20uA or more at least, which is the start-up
current of the IC, needs to be supplied just before of start-up.
During the usual operation, VCC is supplied with the subsidiary
coil of the inductor.
When the power supply voltage is increasing from 0V, FA5550
starts to operate at the voltage of 9.6V (typ) and FA5551 at the
voltage of 13V (typ).
Both ICs stop to operate at the voltage of 9V (typ) when the
power supply voltage is decreasing after start-up of the
operation.
During the period when the low voltage malfunction prevention
circuit is activated and the IC is stopped, OUT pin is made to
“Low” and the output is interrupted.
(Supplementary explanations)
The low voltage malfunction prevention function is a function to
prevent malfunctions of the circuit at the power supply voltage
lowering.
FA5550 / 51
13
VCC
VCC
Fuji Electric Device Technology
Fig.15 VCC pin circuit (1)
Fig.16 VCC pin circuit (2)
8
8
Power Supply
External DC