HA16178P Datasheet, PDF (22/25 Pages) Renesas Technology Corp – Power Factor Correction Controller IC

HA16178P/FP
Precautions on Usage
1. CS Pin
The CS pin is used to for detection in PFC control led current. When power supply is started up, the voltage drop of
inrush current must not exceed the maximum rated value of the CS pin.
2. VREF Pin
For stabilization, be sure to connect a capacitor between the pin and ground. It possible to occur overshoot of VREF by
connected capacitance. The degree of the overshoot will depend on the value of the connected capacitor. Pay particular
attention to this point if you intend to use the VREF pin voltage as reference voltage for an external circuit.
Vref Overshoot
7
6.5
6
5.5
5
0.01
0.1
1
Cref (µF)
Figure 4 Overshoot on the VREF Pin vs. Capacitance
3. PFC-ON Pin
In design of worldwide power supply, it is possible that calculated voltage exceed maximum rated voltage of PFC-ON
pin. Actually, as a clamp circuit is included in the PFC-ON pin, the voltage is clamped however, clamp current must
not exceed 300 µA.
4. OUT Pin
Undershooting or overshooting may occur due to the wiring of the OUT pin. These may bring to malfunctions of the IC.
In such a case, prevent the undershooting or overshooting by using a Schottky barrier diode, etc.
5. Pattern Layout
In designing the pattern layout, pay as much attention as is possible to the following points.
(1) Place the stabilizing capacitor for the VREF pin as close to the IC as possible, and keep the wiring short.
(2) Place the timing resistor of the RT pin as close to the IC as possible, and keep the wiring short.
(3) Place the phase compensation circuit for the CAO pin as close to the IC as possible, and keep the wiring short.
(4) Place the timing capacitor for the CT pin as close to the IC as possible, and keep the wiring short.
(5) Place the stabilizing capacitor for the VCC pin as close to the IC as possible, and keep the wiring short.
(6) Place the IC pins and their wiring as far from high-voltage switching lines (particularly the drain voltage for the
power MOS FET) as possible and in general design the wiring to minimize switching noise.
(7) It is probable that stability of operation is achieved by inputting signals via filters to pins with input functions. Note,
however, that such filter circuits can affect the bias conditions for pins that have both input and output functions.
6. About NC Terminal
NC terminal uses open.
REJ03D0903-0100 Rev.1.00 Jun 12, 2007
Page 22 of 24