TPS61193-Q1 Datasheet, PDF (16/35 Pages) Texas Instruments – High-Performance 3-Channel LED Driver

TPS61193-Q1
SNVSAC7 – OCTOBER 2015
www.ti.com
7.3.4.2 Overview of the Fault/Protection Schemes
Summary of TPS61193-Q1 fault detection behavior is shown in Table 3. Detected faults (excluding LED open or
short) cause device to enter FAULT_RECOVERY state. In FAULT_RECOVERY the DC-DC and LED current
sinks of the device are disabled and FAULT pin is pulled low. The device recovers automatically and enters
normal operating mode (ACTIVE) after a recovery time of 100ms if the fault condition has disappeared. When
recovery is succesful, FAULT pin is released.
In case a LED fault is detected, device continues normal operation and only the faulty string is disabled. Fault is
indicated via FAULT pin which can be released by toggling VDDIO/EN pin low for a short period of 2…20 µs.
LEDs are turned off for this period but device stays in ACTIVE mode. If VDDIO/EN is low longer, device goes to
STANDBY and restarts when EN goes high again.
Table 3. Fault Detections
FAULT/
PROTECTION
FAULT NAME
THRESHOLD
VIN
overvoltage
protection
VIN
undervoltage
lockout
VIN_OVP
1. V_IN > 42 V
2. V_OUT >
V_{SET_DCDC} + 6..10
V.
V_{SET_DCDC} is
voltage value
defined by logic
during adaptation
VIN_UVLO
Falling 3.9 V
Rising 4 V
Open LED fault
OPEN_LED
LOW_COMP
threshold
Shorted LED
fault
SHORT_LED
Shorted string
detection level 6 V
Thermal
protection
TSD
165ºC
Thermal shutdown
hysteresis 20ºC
FAULT
PIN
Yes
Yes
Yes
Yes
Yes
FAULT_
RECOVERY
STATE
ACTION
1. Overvoltage is monitored from the beginning of soft
start. Fault is detected if the duration of overvoltage
condition is 100 µs minimum.
2. Overvoltage is monitored from the beginning of
Yes
normal operation (ACTIVE mode). Fault is detected if
over-voltage condition duration is 560 ms minimum
(t_filter). After the first fault, detection filter time is reduced
to 50 ms for following recovery cycles. When device
recovers and has been in ACTIVE mode for 160 ms ,
filter time is increased back to 560 ms .
Detects undervoltage condition at VIN pin. Sensed in all
Yes
operating modes. Fault is detected if undervoltage
condition duration is 100 µs minimum.
Detected if the voltage of one or more current sinks is
below threshold level, and DC-DC adaptive control has
reached maximum voltage. Open string is removed from
the DC-DC voltage control loop and current sink is
No
disabled.
Fault pin is released by toggling VDDIO/EN pin. If
VDDIO/EN is low for a period of 2…20 µs, LEDs are
turned off for this period but device stays ACTIVE. If
VDDIO/EN is low longer, device goes to STANDBY and
restarts when EN goes high again.
Detected if the voltage of one or more current sinks is
above shorted string detection level and at least one
OUTx voltage is within headroom window. Shorted string
is removed from the DC-DC voltage control loop and
No
current sink is disabled.
Fault pin is released by toggling VDDIO/EN pin. If
VDDIO/EN is low for a period of 2…20 µs, LEDs are
turned off for this period but device stays ACTIVE. If
VDDIO/EN is low longer, device goes to STANDBY and
restarts when EN goes high again..
Thermal shutdown is monitored from the beginning of
Yes
soft start. Die temperature must decrease by 20ºC for
device to recover.
16
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