SG6932DZ Fairchild Semiconductor, SG6932DZ Datasheet - Page 13

• Manufacturer Part Number: SG6932DZ
• Description: IC PFC CONTROLLER CCM 16DIP
• Manufacturer: Fairchild Semiconductor

Specifications of SG6932DZ

• Mode: Continuous Conduction (CCM)
• Frequency - Switching: 65kHz
• Current - Startup: 10µA
• Voltage - Supply: 14 V ~ 20 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: 16-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

© 2007 Fairchild Semiconductor Corporation
SG6932 • Rev. 1.1.3
Functional Description
The highly integrated SG6932 is designed for power
supplies with boost PFC and forward PWM. It requires
very few external components to achieve versatile
protections and compensation.
The
synchronizes the PFC and PWM stages and reduces
switching noise. At light load, the switching frequency is
linearly decreased to reduce power consumption.
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 SG6932 shuts off PFC to prevent extra-
high voltage on output.
For the forward PWM, the synchronized slope
compensation ensures the stability of the current loop
under continuous-mode operation. Hiccup operation
during output overloading is guaranteed. To prevent the
power supply from drawing large current during start-
up, the start-up for PWM stage is delayed 4ms after the
PFC output voltage reaches its set value.
SG6932 provides complete protection functions, such
as brownout protection and built-in latch for over-
voltage and RI open/short.
I
Figure 24 shows the IAC pin connected to input voltage
by a resistor and the current, I
multiplier. For the linear range of I
range input voltage should be connected to a
resistance over 1.2MΩ.
AC
Signal
control.
proprietary
Figure 24. Input Voltage Detection
The
proprietary switching charge
interleave-switching
AC,
is the input for PFC
AC
0~360μA, the
feature
13
Switching Frequency / Current Sources
The switching frequency can be programmed by the
resistor R
The relationship is:
For example, a 24kΩ resistor R
switching frequency. Accordingly, constant current I
flows through R
I
Line Voltage Detection (VRMS)
Figure 25 shows a resistive divider with low-pass
filtering for line-voltage detection on the VRMS pin. The
V
brownout protection. For brownout protection, when the
V
Interleave Switching
The SG6932 uses interleaved switching to synchronize
the PFC and PWM stages. This reduces switching
noise and spreads the EMI emissions. Figure 26 shows
off-time (t
gate drives and the turn-on of the PWM.
T
OPFC
OPWM
RMS
RMS
0.47µF~4.7µF
is used to generate internal current reference.
Figure 25. Line-Voltage Detection on VRMS Pin
voltage drops below 0.8V, OPFC turns off.
voltage is used for the PFC multiplier and
OFF
I
Figure 26. Interleaved Switching
connected between the RI and GND pins.
) inserted between the turn-off of the PFC
f
PWM
I
:
I
T
=
=
R
1
R
1560
I
2 .
k (
I
( )
kΩ
V
Ω
)
(mA)
T
t
(
OFF
kHz
OFF
)
I
results in a 65kHz
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(1)
(2)
T