CDB1601-120W-Z Cirrus Logic Inc, CDB1601-120W-Z Datasheet - Page 12

• Manufacturer Part Number: CDB1601-120W-Z
• Description: High-efficiency PFC Demo. Board
• Manufacturer: Cirrus Logic Inc
• Series: -r

Specifications of CDB1601-120W-Z

• Silicon Manufacturer: Cirrus Logic
• Kit Application Type: Power Management
• Application Sub Type: Power Factor Correction (PFC)
• Kit Contents: Board, Datasheet
• Design Resources: CS150x/160x PCB Layout Guidelines
• Featured Product: CS1501/CS1601 Power Factor Correction IC Controllers
• Main Purpose: Power Management, Power Factor Correction
• Embedded: No
• Utilized Ic / Part: CS1601
• Primary Attributes: 108 ~ 305 VAC Input, 460V 120W Output
• Secondary Attributes: Ballast Control, Up to 2 T5 Lamps
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

table below depicts approximate values for R3 and R4 for a
range of boost-to-auxiliary inductor turns ratio, N.
Resistors R3 and R4 were calculated using V
C
Equation 6 is used to calculate the cut-off frequency defined
by the RC circuit at the ZCD pin.
where:
f
C
5.8 Brownout Protection
The CS1601 brownout detection circuit monitors the peak of
the V
it drops below a pre-determined threshold. Hysteresis and
minimum detection time are provided to avoid brownout
detection during short input transients. When brownout is
detected, the CS1601 enters standby mode. On recovery from
brownout, it re-enters normal operating mode.
Current I
V
The digitized current applied to the IAC pin is monitored by the
brownout protection algorithm. When V
brownout detection threshold, the CS1601 triggers a timer.
The IC asserts the brownout protection and stops the gate-
drive switching only if the timer exceeds 56ms. This is the
equivalent of 7 rectified line cycles at 60Hz.
During the brownout state, the device continues monitoring
the input line voltage. The device exits the brownout state
when I
56ms. Typical values for the lower (I
(I
respectively.
12
c
rect
BP(upper)
p
p
= 10pF.
Table 1. Aux Inductor Turns Ratio vs. R3 and R4
= R
rect
AC
AC
IAC
The cut-off frequency, f
frequency.
Capacitance at the ZCD pin
input voltage and disables the PWM switching when
) brownout thresholds are 31.6A and 39.6A,
exceeds the brownout upper threshold for at least
is proportional to the AC input voltage V
xI
10
11
12
13
14
15
N
9
AC
and R
f
c
=
1
IAC


37.5k
35.5k
29.5k
27.5k
2 R3 R4
= R1+R2 in Figure 19 on page 11.
46k
42k
32k
~R3

c
, needs to be 10x the ringing

C
BP(lower)
rect
p

1.75k
1.75k
1.75k
1.75k
1.75k
1.75k
1.75k
~R4
drops below the
link =
) and upper
rect
460V and
, where
[Eq.6]
Thresholds
The overpower protection may activate prior to brownout
protection, depending on the load.
The maximum response time of the brownout protection
feature occurs at light-load conditions. It is calculated by
Equation 7.
where:
V
5.9 Overvoltage Protection
The overvoltage protection (OVP) will trigger immediately and
stop the gate drive when the current into the IFB pin (I
exceeds 105% of the reference current (I
resumes gate drive switching when the measured current at IFB
drops below I
OVP threshold (V
5.10
To limit boost inductor current through the FET and to prevent
boost inductor saturation conditions, the CS1601 incorporates
a cycle-by-cycle peak inductor current limit circuit using an
external shunt resistor to ‘sense’ the FET source current
accurately. The overcurrent protection (OCP) circuit is
designed to monitor the current when the active switch is
turned on. The OCP circuit is enabled after the leading-edge
blanking time (t
reference voltage, V
overcurrent condition exists. The OCP circuit triggers
immediately, allowing the OCP algorithm to turn off the gate
driver.
The overcurrent protection circuit is also designed to monitor
for a catastrophic overcurrent occurrence by sensing sudden
and abnormal operating currents. A second OCP threshold,
V
exists. This immediately turns off the gate drive and the
system enters a restart mode. The CS1601 inhibits all
switching operations for approximately 1.6ms then attempts to
restart normal operation.
Brownout
T
BP(th)
cs(clamp)
Upper
Lower
Brownout
Brownout threshold voltage, V
Overcurrent Protection
, determines whether a severe overcurrent condition
=
=
OVP
Figure 22. Brownout Sequence
8 ms
8
+
V
LEB
OVP
– I
OVP
8
-- - 128 94.8
5
OVP(Hy)

+
). The shunt voltage is compared to a
).
8 ms
----------- - 128 V V
5 V
=
Enter Standby
c s ( t h )
T
–
R
Brownout
. Equation 8 is used to calculate the

IFB
56 ms
Timer
Start
Start Timer
, to determine whether an


+
I
OVP
–
56
BP(th) =
BP th
+
=

V
117ms
DD

ref

56 ms
I
+
BP(lower)
) value. The IC
56 ms
Exit Standby
DS931PP6
xR
[Eq.7]
[Eq.8]
IAC
OVP
)