TPS61193

SNVSAF4 – OCTOBER 2015

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7.3.4.2 Overview of the Fault/Protection Schemes

Summary of TPS61193 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_

FAULT/

FAULT

FAULT NAME

THRESHOLD

RECOVERY

ACTION

PROTECTION

PIN

STATE

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

VIN

V.

normal operation (ACTIVE mode). Fault is detected if

overvoltage

VIN_OVP

Yes

Yes

over-voltage condition duration is 560 ms minimum

protection

voltage value

defined by logic

to 50 ms for following recovery cycles. When device

during adaptation

recovers and has been in ACTIVE mode for 160 ms ,

filter time is increased back to 560 ms .

VIN

Detects undervoltage condition at VIN pin. Sensed in all

Falling 3.9 V

undervoltage

VIN_UVLO

Yes

Yes

operating modes. Fault is detected if undervoltage

Rising 4 V

lockout

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

LOW_COMP

disabled.

Open LED fault

OPEN_LED

Yes

No

threshold

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

Shorted LED

Shorted string

current sink is disabled.

SHORT_LED

Yes

No

fault

detection level 6 V

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..

165ºC

Thermal shutdown is monitored from the beginning of

Thermal

TSD

Thermal shutdown

Yes

Yes

soft start. Die temperature must decrease by 20ºC for

protection

hysteresis 20ºC

device to recover.

16

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