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| TLD1314EL_15 Datasheet, PDF (16/29 Pages) Marl International Limited – Basic LED Driver | |||
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7
ST Pin
The ST pin is a multiple function pin.
TLD1314EL
ST Pin
IST(OL/SC)
No fault
ST
Fault
VST(OL/SC)
Output Control
No fault
Fault
VST
IST(PD)
Figure 12 Block Diagram ST pin
7.1
Diagnosis Selector
If the voltage at the DEN pin VDEN is higher than VDEN(act), the diagnosis is activated. For details, please refer to
Chapter 5. If the status pin is unconnected or connected to GND via a high ohmic resistor (VST to be below VST(L)),
the ST pin acts as diagnosis output pin. In normal operation (device is activated) the ST pin is pulled to GND via
the internal pull down current IST(PD). In case of an open load or short circuit to GND condition the ST pin is switched
to VST(OL/SC) after the open load or short circuit detection filter time (Pos. 8.3.9, Pos. 8.3.12).
If the device is operated in PWM operation via the VS pin the ST pin should be connected to GND via a high ohmic
resistor (e.g. 470kΩ) to ensure proper device behavior during fast rising VS slope.
If the ST pin is shorted to GND the diagnostic feedback is performed via the IN_SET-pin, which is shown in
Chapter 6.2 and Chapter 8.
7.2
Diagnosis Output
If the status pin is unconnected or connected to GND via a high ohmic resistor (VST to be below VST(L)), it acts as
a diagnostic output, if the voltage at the DEN pin is above VDEN(act). In case of a fault condition the ST pin rises its
voltage to VST(OL/SC) (Pos. 8.3.7). Details are shown in Chapter 8.
7.3
Disable Input
If an external voltage higher than VST(H) (Pos. 8.3.5) is applied to the ST pin, the device is switched off. This
function is working independently of the voltage at the DEN pin. Even if the diagnosis is disabled via
VDEN < VDEN(dis) the disable function of the ST pin is working. This function is used for applications, where multiple
drivers should be used for one light function. It is possible to combine the driversâ fault diagnosis via the ST pins.
If a single LED chain fails, the entire light function is switched off. In this scenario e.g. the diagnostic circuit on the
body control module can easily distinguish between the two cases (normal load or load fault), because nearly no
current is flowing into the LED module during the fault scenario - the drivers consume a current of IS(fault,STu)
(Pos. 5.1.4) or IS(dis,ST) (Pos. 5.1.2).
Data Sheet
16
Rev. 1.1, 2015-03-24
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