FSEZ1016A View Datasheet(PDF) - Fairchild Semiconductor
Part Name
Description
Manufacturer
FSEZ1016A Datasheet PDF : 16 Pages
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Protections
The FSEZ1016A has several self-protective functions,
such as Over-Voltage Protection (OVP), Over-
Temperature Protection (OTP), and brownout
protection. All the protections are implemented as auto-
restart mode. When the auto-restart protection is
triggered, switching is terminated and the MOSFET
remains off. This causes VDD to fall. When VDD reaches
the VDD turn-off voltage of 5V, the current consumed by
FSEZ1016A reduces to the startup current (maximum
10µA) and the current supplied startup resistor charges
the VDD capacitor. When VDD reaches the turn-on
voltage of 16V, FSEZ1016A resumes normal operation.
In this manner, the auto-restart alternately enables and
disables the switching of the MOSFET until the fault
condition is eliminated (see Figure 29).
VDS
Power
On
Fault
Occurs
Fault Removed
VDD
16V
VDD Over-Voltage Protection (OVP)
VDD over-voltage protection prevents damage from over-
voltage conditions. If the VDD voltage exceeds 28V by
open-feedback condition, OVP is triggered. The OVP
has a debounce time (typical 250µs) to prevent false
triggering by switching noise. It also protects other
switching devices from over voltage.
Over-Temperature Protection (OTP)
A built-in temperature-sensing circuit shuts down PWM
output if the junction temperature exceeds 140°C.
Brownout Protection
FSEZ1016A detects the line voltage using auxiliary
winding voltage since the auxiliary winding voltage
reflects the input voltage when the MOSFET is turned
on. The VS pin is clamped at 1.15V while the MOSFET
is turned on and brownout protection is triggered if the
current out of the VS pin is less than IVS-UVP (typical
180μA) during the MOSFET conduction.
Pulse-by-Pulse Current Limit
When the sensing voltage across the current sense
resistor exceeds the internal threshold of 1.3V, the
MOSFET is turned off for the remainder of the switching
cycle. In normal operation, the pulse-by-pulse current
limit is not triggered since the peak current is limited by
the control loop.
5V
Operating Current
3.5mA
10µA
Normal
Operation
Fault
Situation
Normal
Operation
Figure 29. Auto-Restart Operation
© 2009 Fairchild Semiconductor Corporation
FSEZ1016A • Rev. 1.0.2
12
www.fairchildsemi.com
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