SG6980DZ Fairchild Semiconductor, SG6980DZ Datasheet - Page 13

• 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
The average total input power can be expressed as:
From Equation 7, V
amplifier, controls the total input power and the power
delivered to the load.
Multi-Vector Error Amplifier
The voltage-loop error amplifier of SG6980 is
transconductance, which has high output impedance
(> 90k : ). A capacitor C
VEA to ground provides a dominant pole for the voltage
loop. Although the PFC stage has a low bandwidth
voltage loop for better input power factor, the innovative
multi-vector error amplifier provides a fast transient
response to clamp the overshoot and undershoot of the
PFC output voltage. Figure 5 shows the voltage loop with
multi-vector for fast transient error amplifier. When the
variation of the feedback voltage exceeds r 5% of the
reference voltage, the transconductance error amplifier
adjusts its output impedance to increase the loop response.
If the feedback resistance is opened, SG6980 shuts
off immediately to prevent extra-high voltage on the
output capacitor.
FIG. 5 Voltage Error Amplifier with Multi-Vector
© System General Corp.
Version 1.0.1 (IAO33.0064.B0)
Pin
v
v
v
f
1
V
V
V
RMS
RMS
RMS
Vin
2
S
u
u
u
(
I
rms
I
MO
R
u
AC
Vin
V
AC
V
RMS
R
u
)
RMS
u
1
V
u
0
Iin
EA
2
V
u
2
EA
(
rms
C
v
EA
)
V
EA
EA
, the output of the voltage error
EA
----------------------------
(1µF ~ 10µF) connected from
--------------
(7)
(6)
- 13 -
Cycle-by-Cycle Current Limiting
SG6980 provides cycle-by-cycle current limiting for PFC
stages. Figure 6 shows the peak current limit for the PFC
stage. The PFC gate drive is terminated once the voltage
on IPK pin goes below V
The voltage of V
relationship between V
The amplitude of the constant current I
the internal current reference I
Therefore the peak current of the I
Gate Drivers
SG6980 output stages are fast totem-pole gate drivers.
The output driver is clamped by an internal 18V Zener
diode to protect the power MOSFET.
Over-Temperature Protection
SG6980 provides an OTP pin for over-temperature
protection. A constant current is output from this pin. If RI
is equal to 24k , the magnitude of the constant current is
50µA. An external NTC thermistor must be connected
from this pin to ground. When the OTP voltage drops
below 1.2V, SG6980 shuts down. SG6980 auto restarts
when the OTP voltage is higher than 1.4V.
Ip
I
S_peak
2
u
I
T
(Ip
www.sg.com.tw • www.fairchildsemi.com
u
2
R
RMS
u
FIG.6 Current Limit
R
P
1.2V
- )
S
determines the voltage of V
R
PK
V
I
PK
pk
and V
.
-----------------------
T
, according to the equation:
Product Specification
------------------
RMS
S
is given by:
is shown in Figure 6.
September 17, 2007
P
is determined by
SG6980
PK
. The
(8)
(9)