TD230IDT STMicroelectronics, TD230IDT Datasheet - Page 2

• Manufacturer Part Number: TD230IDT
• Description: MOSFET & Power Driver ICs
• Manufacturer: STMicroelectronics

Specifications of TD230IDT

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

This reconduction time can be extended with an
external soft start capacitor C
figure 1 C
C
Figure 1 : Dual Electronic Circuit Breaker
If the fault (over current condition) still remains af-
ter the reconduction state of the MOSFET
been reached, the current through NMOS
overpass the limitation given by equation (i), and
the NMOS
again.
Figure 2 shows the current limitation which is op-
erated on every restart attempt.
Figure 2 : TD230 as Current Limitor
2/8
ISS
+ C
SS 1/2
Application
ISS
.
1/2
will therefore simply be replaced by
will immediately be switched off
SS1/2
as shown in
1/2
1/2
has
will
Trace A represents the Gate-Source Voltage of
the Power Mosfet (0 to 13,4V).
Trace B represents the voltage across the Sense
Resistor (68m ) in direct relation with the current
through it (0 to ~1A).
Note that the first current peak which is due to an
over current is limited only by the reaction time of
the TD230.
This off time is tied to the value of the external soft
start capacitor C
While in current limitation mode, the NMOS
sipates low power due to the fact that the ON/OFF
cycle time rate is very low.
Note that the higher the value of C
more the NMOS
current limitation.
Note that at Power ON, or in the case of live inser-
tion, the inrush current is automatically limited
thanks to the slow gate charge of the MOSFET
which switches ON softly due to the time constant
given in equation (ii).
2.2. Fault Time Limitation
The repetitive switching off of the MOSFET will
come to an end under two conditions :
External line defaults (lightning, line breakage,
etc...) are usual causes for such temporary over
currents.
Equipment faults (component short circuit, over
heat, etc ...) are usual causes for lasting over cur-
rents.
This fault time supervision is done by the compar-
ison of the output voltage to 75% of the nominal
supply voltage. As soon as the output voltage is
detected under 0.75xVcc(+/-), the corresponding
external capacitors C
current source I
across C
NMOS is definitively switched off and the SHUT-
DOWN pin is active low.
t
either the fault has disappeared, and the
current through the shunt resistors R
has come back to its nominal value : the
system keeps running normally.
either the repetitive switching off has lasted
over an externally adjustable time and the
TD230 has definitively switched off the cor-
responding NMOS : the system waits to be
reset.
OFF
TRIP1/2
= R
AN1280 - APPLICATION NOTE
DSON
reaches 1.20V, the corresponding
P/N2
SS 1/2
1/2
x C
will stay in linear mode during
- I
by equation (iii) :
P/N3
TRIP1/2
SS
(iii)
(3 A). When the voltage
is charged by a fixed
SS1/2
are, the
1/2
dis-
S 1/2