SG6980DZ Fairchild Semiconductor, SG6980DZ Datasheet - Page 11

• 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 SG6980 is designed for a power
supply with boost PFC. It requires very few external
components to achieve high performance and includes
versatile protections / compensation.
The PFC function is implemented by average current
mode
multiplier-divider provides a high-degree of noise
immunity for the PFC circuit. This 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 SG6980 shuts
off PFC to prevent extra-high voltage on output.
Programmable two-level high/low line compensation
optimizes THD performance.
In addition, SG6980 provides complete protection
functions, such as brownout and RI open/short.
Switching Frequency and Current
Sources
The switching frequency of SG6980 can be programmed
by the resistor R
The 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.
© System General Corp.
Version 1.0.1 (IAO33.0064.B0)
I
f
T
T
PWM
is used to generate internal current reference.
R
1.2V
I
control.
R
(k
1560
I
:
(k
)
:
I
.
(mA
I
)
connected between RI pin and GND.
(kHz
The
)
----------------
resistor R
)
-------------
patented
I
results in a 65kHz
switching-charge
(1)
(2)
- 11 -
T
Line Voltage Detection (V
Figure 1 shows a resistive divider with low-pass filtering
for line-voltage detection on the VRMS pin. The V
voltage is used for the PFC multiplier, brownout
protection, and RDY control.
For brownout protection, the SG6980 is disabled with
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
FIG.1
R

B
R
B
www.sg.com.tw • www.fairchildsemi.com
u
3
V
----
Product Specification
RMS
RMS
September 17, 2007
drops below 0.8V.
)
SG6980
RMS
(3)