CS1600-FSZ Cirrus Logic Inc, CS1600-FSZ Datasheet - Page 10

• Manufacturer Part Number: CS1600-FSZ
• Description: IC PFC CONTROLLER DCM 8SOIC
• Manufacturer: Cirrus Logic Inc
• Series: EXL Core™r

Specifications of CS1600-FSZ

• Package / Case: 8-SOIC (3.9mm Width)
• Mode: Discontinuous Conduction (DCM)
• Frequency - Switching: 66kHz
• Current - Startup: 68µA
• Voltage - Supply: 7.9 V ~ 17 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Maximum Power Dissipation: 600 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 598-1801

5.7 Brownout Protection
As an added protection to the PFC boost stage, the CS1600
includes a failure mechanism that detects high average
currents that occur under abnormal brownout conditions. The
brownout protection feature monitors the V
suspends the gate-drive switching when a brownout threshold
breach is detected. Under normal conditions, the CS1600 will
never reach the brownout threshold, as the PFC stage is
automatically protected by the power limitation of Equation 2,
see section 5.4 Output Power and PFC Boost Inductor on
page 9. In the event that the boost inductor is significantly less
than the target value of L
may be breached. However, under normal operating
conditions with proper boost inductance, this will not occur.
If a brownout event is detected, the CS1600 enters standby,
and upon recovery from brownout enters normal operation
mode. In order to avoid an erroneous brownout detection,
hysteresis and minimum detection time is implemented to
avoid brownout detection during input transients. Figure 5.8
illustrates the brownout entry and exit timing. If the input line
voltage is lower than the threshold for a fixed period of time, a
brownout is declared. The measured voltage decreases at a
rate of 5 V / half-line-cycle (~8 ms for 60 Hz line frequency).
The CS1600 triggers a timer when the measured voltage falls
below the lower brownout threshold. The IC asserts the
brownout protection and stops the gate-drive switching only if
the timer reaches more than 56 ms, which is determined by
the minimum line frequency..
10
Thresholds
Brownout
Upper
Lower
Figure 18. Brownout Sequence
Enter Standby
B
T
Brownout
, the brownout protection threshold
56 ms
Timer
Start
Start Timer
rect
56 ms
input signal and
Exit Standby
During the brownout state, the device continues monitoring
the input line voltage. The device exits the brownout state
when the input voltage peak value exceeds the brownout
upper threshold for at least 56 ms.
The maximum response time of the brownout protection
normally happens at light-load conditions. It can be calculated
by the following equation:
5.8
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 value (I
resumes gate drive switching when the link voltage drops
below V
5.9 Open/Short Loop Protection
If the PFC output sense resistor R
GND), the measured output voltage decreases at a slew rate
of about 2V / s, which is determined by ADC sampling rate.
The IC stops the gate drive when the measured output voltage
is lower than the measured line voltage. The IC resumes gate
drive switching when the current into the IFB pin becomes
larger than or equal to the current into the IAC pin and V
greater than the peak of the line voltage (V
maximum response time of open/short loop protection for R
is about 150 s in the CS1600.
If the PFC input sense resistor R
GND), the current reference signal supplied to the IC on pin
IAC falls to zero.
T
Brownout
OVP
Overvoltage Protection
– V
=
=
=
8 ms
8
116.8 ms
OVP(HY)
+
8
-- - 128 95
5
+
8 ms
----------- - 128 V V
5 V
.
–
+
56
–
IAC
IFB
BP th
fails (open or short to
fails (open or short to
+
CS1600
56 ms
rect(pk)
ref
DS904F1
). The IC
). The
[Eq.6]
link
OVP
IFB
is
)