Pin connections and function VIPer53 - E
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Table 10. Pin function
Pin Name Pin function
V
DD
Power supply of the control circuits. Also provides the charging current of the external
capacitor during start-up. The functions of this pin are managed by four threshold
voltages:
- VDDon: Voltage value at which the device starts switching (Typically 11.5 V).
- VDDoff: Voltage value at which the device stops switching (Typically 8.4 V).
- VDDreg: Regulation voltage point when working in primary feedback
(Trimmed to 15 V).
- VDDovp: Triggering voltage of the overvoltage protection (Trimmed to 18 V).
SOURCE Power MOSFET source and circuit ground reference.
DRAIN
Power MOSFET drain. Also used by the internal high voltage current source during the
start-up phase to charge the external V
DD
capacitor.
COMP
Input of the current mode structure, and output of the internal error amplifier. Allows
the setting of thedynamic characteristic of the converter through an external passive
network. The useful voltage range extends from 0.5V to 4.5V. The Power MOSFET is
always off below 0.5V, and the overload protection is triggered if the voltage exceeds
4.35V. This action is delayed by the timing capacitor connected tothe TOVL pin.
TOVL
Allows the connection of an external capacitor for delaying the overload protection,
which is triggered by a voltage on the COMP pin higher than 4.35V.
OSC Allows the setting of the switching frequency through an external Rt-Ct network.
