R2A20111DD RENESAS [Renesas Technology Corp], R2A20111DD Datasheet - Page 37

• Manufacturer Part Number: R2A20111DD
• Description: Power Factor Correction Controller IC
• Manufacturer: RENESAS [Renesas Technology Corp]

R2A20111SP/DD
5. Precautions on Pins
5-1. OUT Pin
Undershoot may occur on the PWM pulse of the OUT pin because of a parasitic inductance of wiring, etc. This
undershoot (negative electric potential) may cause errors of the IC. In such a case, use a Schottky barrier diode, etc. to
suppress the undershoot.
5-2. DELAY Pin
When the voltage on the DELAY pin reaches 4 V or more, the shutdown function is operated and the IC enters the
shutdown state. Since the shutdown state is in latch mode, the IC is not resumed unless the voltage on the VCC pin is,
once, lowered to 4 V or below.
When the PFC hold function is not used, lower the DELAY pin capacitance as possible. However, connect a capacitor
with a few thousands pF or more capacitance to the DELAY pin so that the shutdown function will not be operated due
to noise, etc. and note wiring pattern not to catch the noise.
5-3. CAI Pin and CLIMIT Pin
These pins are connected to a current detection resistor via a resistor. Provide a rush-current protection circuit, not to
exceed the maximum rating because of the rush current at the startup of power supply.
5-4. VREF Pin
The voltage on the VREF pin is a reference voltage in the IC. For stabilizing the voltage on the VREF pin, be sure to
connect a capacitor between the VREF pin and GND. However, in capacitance of a capacitor to be connected,
overshoot may occur at the rising of the VREF pin (see figure 24). Pay special attention to this point when the voltage
on the VREF pin is used as the power supply for an external circuit and a reference voltage.
Furthermore, note that the source current of the VREF pin will not exceed the maximum rating.
REJ03F0231-0100 Rev.1.00 Mar 28, 2007
Page 37 of 40
Figure 24 Overshoot Amount on VREF Pin (Reference Data)
6.5
5.5
0.01
7
6
5
Vref Overshoot
Cref ( F)
0.1
1