NCP1607BDR2G ON Semiconductor, NCP1607BDR2G Datasheet - Page 17

• Manufacturer Part Number: NCP1607BDR2G
• Description: IC PFC CONTROLLER CRM 8SOIC
• Manufacturer: ON Semiconductor

Specifications of NCP1607BDR2G

• Mode: Critical Conduction (CRM)
• Current - Startup: 23.5µA
• Voltage - Supply: 9.5 V ~ 20 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Switching Frequency: 70 KHz
• Maximum Power Dissipation: 450 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

STATIC OVERVOLTAGE PROTECTION
that the error amplifier output reaches its minimum level
(i.e. Control = V
current and maintain the OVP fault. Therefore, to avoid any
discontinuity in the OVP disabling effect, the circuit
incorporates a comparator which detects when the lower
level of the error amplifier is reached. This event, called
“static OVP”, disables the output drives. Once the OVP
event is over, and the output voltage has dropped to normal,
then Control rises above the lower limit and the driver is
re−enabled (Figure 35).
NCP1607 Undervoltage Protection (UVP)
forced to roughly equate the peak line voltage. The
NCP1607 detects an undervoltage fault when this output
voltage is unusually low, such that the feedback voltage is
below V
output and error amplifier (EA) are disabled. The latter is
done so that the EA does not source a current which would
increase the FB voltage and prevent the UVP event from
being accurately detected. The UVP feature helps to
protect the application if something is wrong with the
power path to the bulk capacitor (i.e. the capacitor cannot
charge up) or if the controller cannot sense the bulk voltage
(i.e. the feedback loop is open).
sequence which ensures that undervoltage conditions are
always detected at startup. It accomplishes this by waiting
approximately 180 ms after V
enabling the error amplifier (Figure 36). During this wait
time, it looks to see if the feedback (FB) voltage is greater
than the UVP threshold. If not, then the controller enters a
UVP fault and leaves the error amplifier disabled.
If the OVP condition lasts for a long time, it may happen
When the PFC stage is plugged in, the output voltage is
Furthermore, the NCP1607 incorporates a novel startup
I
V
V
I
OVPH
OVPL
EAH
EAL
UVP
Figure 35. OVP Timing Diagram
(300 mV typical). In an UVP fault, the drive
V
EAL
OUT
). It would then not be able to sink any
DRV
I
Dynamic OVP
CONTROL
Static OVP
V
CONTROL
CC
reaches V
CC(on)
http://onsemi.com
before
17
However, if the FB pin voltage increases and exceeds the
UVP level, then the controller will start the application up
normally.
given by:
UVP threshold is 48 V. This corresponds to an input voltage
of approximately 34 Vac.
Open Feedback Loop Protection
against open feedback loop conditions by including OVP,
UVP, and Floating Pin Protection (FPP). Figure 37
illustrates three conditions in which the feedback loop is
open. The corresponding number below describes each
condition shown in Figure 37.
V
V
The voltage on the output which exits a UVP fault is
If R
The NCP1607 features comprehensive protection
CC(on)
CC(off)
Figure 36. The NCP1607’s Startup Sequence with
V
2.5 V
V
V
V
1. UVP Protection: The connection from resistor
2. OVP Protection: The connection from resistor
3. FPP Protection: The FB pin is floating. The
UVP
OUT
EAH
EAL
OUT1
R
the FB pin to ground. The UVP comparator
detects a UVP fault and the drive is disabled.
R
FB pin to the output voltage. The ESD diode
clamps the FB voltage to 10 V and R
the current into the FB pin. The V
detects a static OVP fault and the drive is
disabled.
internal pulldown resistor R
voltage below the UVP threshold. The UVP
comparator detects a UVP fault and the drive is
disabled.
OUT1
OUT2
Control
FB
V
UVP
V
V
= 4 MW and R
CC
OUT
OUT(UVP)
to the FB pin is open. R
to the FB pin is open. R
and without a UVP Fault
+
UVP Fault is “Removed”
R
EQ
OUT1
UVP Wait
R
= 25.16 kW, then the V
EQ
) R
FB
EQ
pulls down the FB
OUT2
OUT1
@ V
EAL
UVP
pulls down
pulls up the
OUT1
clamp
UVP Wait
(eq. 15)
limits
OUT