SG6980DZ Fairchild Semiconductor, SG6980DZ Datasheet - Page 12

• Manufacturer Part Number: SG6980DZ
• Description: IC PFC CTRLR AVERAGE CURR 16DIP
• Manufacturer: Fairchild Semiconductor

Specifications of SG6980DZ

• Mode: Average Current
• Frequency - Switching: 65kHz
• Current - Startup: 10µA
• Voltage - Supply: 12.5 V ~ 20 V
• Operating Temperature: -20°C ~ 125°C
• Mounting Type: Through Hole
• Package / Case: 16-DIP (0.300", 7.62mm)
• Output Voltage: 0.3 V to 25 V
• Switching Frequency: 68 KHz
• Operating Temperature Range: - 20 C to + 125 C
• Mounting Style: Through Hole
• Duty Cycle (max): 98 %
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Single-Stage PFC Controller
OPERATION DESCRIPTION
The highly integrated SG6980D is designed for a power
supply with boost PFC. It requires very few external
components to achieve high performance and versatile
protections / compensation.
The PFC function is implemented by average current mode
control. The patented switching-charge multiplier-divider
provides a high-degree of noise immunity for the PFC
circuit. This also enables the PFC circuit to operate over a
much wider region. The proprietary multi-vector output
voltage control scheme provides a fast transient response in
a low-bandwidth PFC loop, in which the overshoot and
undershoot of the PFC voltage are clamped. If the feedback
loop is broken, the SG6980D shuts off the PFC to prevent
extra-high voltage on output. Programmable two-level
high/low line compensation optimizes THD performance.
In addition, SG6980D provides complete protection
functions, such as brownout protection and RI open/short.
Switching Frequency and Current
Sources
The switching frequency of SG6980D can be programmed
by the resistor R
relationship is:
For example, a 24k
switching frequency. Accordingly, constant current I
flows through R
I
If there is a SYNC signal input, the switching frequency is
defined by the SYNC signal. The SNYC frequency must be
larger than the programmed switching frequency,
less 6KHz.
Line Voltage Detection (V
Figure 1 shows a resistive divider with low-pass filtering
for line-voltage detection on VRMS pin. The V
is used for the PFC multiplier, brownout protection, and
RDY control.
© System General Corp.
Version 1.0.1 (IAO33.0071.B0
I
f
T
T
PWM
is used to generate internal current reference.
R
1.2V
I
R
(k
1560
I
:
(k
)
I
I
:
:
connected between RI pin and GND. The
(mA
)
(kHz
)
----------------
resistor R
)
-------------
I
RMS
results in a 65kHz
)
RMS
voltage
(1)
(2)
- 12 -
T
For brownout protection, the SG6980D is disabled with a
195ms delay time if the voltage V
For PFC multiplier and RDY control, please refer to below
sections for more detail.
PFC Output Voltage Control
For a universal input (90VAC ~ 264VAC) power supply
applying active boost PFC and forward as a second stage,
the output voltage of PFC is usually designed around 400V.
FIG.2 Output Voltage Setting
Vo
R
A
R

B
R
B
www.sg.com.tw • www.fairchildsemi.com
u
3
FIG.1
V
----
Product Specification
RMS
drops below 0.8V.
September 17, 2007
SG6980D
(3)