CS1601
2. PIN DESCRIPTION
Link V oltage S ens e
S tandby
Rec tifier V oltage S ens e
P FC Current S ens e
IFB
S TBY
IAC
CS
1
2
3
4
8
7
6
5
V DD
GD
GND
ZCD
IC S upply V oltage
P FC Gate Driv er
Ground
P FC Zero-c urrent Detec t
8-lead S OIC
Figure 2. CS1601 Pin Assignments
Pin Name
IFB
STBY
IAC
Pin #
I/O
Description
Link Voltage Sense
— A current proportional to the output link voltage of the PFC is
input into this pin. The current is measured with an ADC.
Standby
— A voltage below 0.8V puts the IC into a non-operating, low-power state.
The input has an internal 600k pull-up resistor to the V
DD
pin.
Rectifier Voltage Sense
— A current proportional to the rectified line voltage is input
into this pin. The current is measured with an ADC.
PFC Current Sense
— The current flowing in the PFC MOSFET is sensed through a
resistor. The resulting voltage is applied to this pin and digitized for use by the PFC
computational logic to limit the maximum current through the power FET.
Zero-current Detect—
Boost Inductor demagnetization sensing input for zero-current
detection (ZCD) information. The pin is externally connected to the PFC boost inductor
auxiliary winding through an external resistor divider.
Ground
— Common reference. Current return for both the input signal portion of the IC
and the gate driver.
PFC Gate Driver
— The totem pole stage is able to drive the power MOSFET with a
peak current of 0.5A source and 1.0A sink.
IC Supply Voltage
— Supply voltage of both the input signal portion of the IC and the
gate driver. A storage capacitor is connected on this pin to serve as a reservoir for oper-
ating current for the device, including the gate drive current to the power transistor. This
pin is clamped to a maximum voltage (V
z
) by an internal zener function.
1
2
3
IN
IN
IN
CS
4
IN
ZCD
5
6
7
IN
PWR
OUT
GND
GD
V
DD
8
PWR
DS931PP6
3
CIRRUS [ CIRRUS LOGIC ]
