Output voltage monitor and protections
L6713A
Figure 22. Output voltage protections and typical principle connections
Vcc
UVLOVCC
UVLOOVP
(OUTEN = 0)
Preliminary OVP
VSEN Monitored
(OUTEN = 1)
Programmable OVP
VSEN Monitored
Preliminary OVP Enabled
VSEN Monitored
No Protection
Provided
+5V
SB
BAT54C
+12V
2.2Ω
2.2Ω
VCC
1μF
VCCDR1
VCCDR2
VCCDR3
17.3
Over voltage and programmable OVP
Once VCC crosses the turn-ON threshold and the device is enabled (OUTEN = 1), L6713A
provides an over voltage protection: when the voltage sensed by VSEN overcomes the OVP
threshold, the controller permanently switches on all the low-side MOSFETs and switches
OFF all the high-side MOSFETs in order to protect the load. The OSC/ FAULT pin is driven
high (5 V) and power supply or OUTEN pin cycling is required to restart operations.The OVP
Threshold varies according to the operative mode selected (See Table 12).
The OVP threshold can be also programmed through the OVP pin: leaving the pin floating, it
is internally pulled-up and the OVP threshold is set according to Table 12. Connecting the
OVP pin to SGND through a resistor ROVP, the OVP threshold becomes the voltage present
at the pin. Since the OVP pin sources a constant IOVP = 12.5 μA current(See Table 5), the
programmed voltage becomes:
OVPTH = ROVP ⋅ 12.5μA
⇒
ROVP
=
-O-----V----P----T---H--
12.5μA
Filter OVP pin with 100 pF(max) vs. SGND.
17.4
PGOOD (only for AMD mode)
It is an open-drain signal set free after the soft-start sequence has finished. It is pulled low
when the output voltage drops below -300 mV of the programmed voltage.
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