ZHCSC40E February 2014 – May 2018 TPS92630-Q1
PRODUCTION DATA.
Detection of an open-load condition occurs when the voltage across the channel, V(VIN) – V(IOUTx), is less than the open-load detection voltage, V(OLV). When this condition is present for more than the open-load-detection deglitch (2 ms when PWM is 100% on or one PWM on-time is more than 2 ms, or seven continuous PMW duty cycles when in PWM dimming mode), the FAULT pin goes low, keeping the open channel on and turning the other channel off. With the FAULT pin tied high, all channels remain turned on. The channel recovers on removal of the open condition. Note that the device can detect an open load if the sum of the forward voltages of the LEDs in a string is close to or greater than the supply voltage on VIN.
FAILURE MODE | JUDGMENT CONDITION | DIAGNOSTIC OUTPUT PINS | ACTION | FAULT AND FAULT_S(3) | DEVICE REACTION | FAILURE
REMOVED |
SELF-
CLEARING |
||
---|---|---|---|---|---|---|---|---|---|
DETECTION
VIN VOLTAGE |
CHANNEL STATUS | DETECTION MECHANISM | |||||||
Short circuit:
1 or several LED strings |
V(VIN) > 5 V | ON | V(IOUTx) < 0.9 V | FAULT | Pulled low | Externally
pulled high |
Failing strings turned off, other channels on | Toggle EN,
power cycle |
No |
Floating | All strings turned OFF | Toggle EN,
power cycle |
|||||||
Single-LED short circuit:
1 or several LED strings |
V(VIN) > 9 V | ON | V(VSNSx) < 1.222 V | FAULT_S | Pulled low | Externally
pulled high |
All strings stay ON | Toggle EN,
power cycle |
No |
Floating | All strings stay ON | Toggle EN,
power cycle |
|||||||
Open load:
1 or several LED strings |
V(VIN) > 5 V | ON | V(VIN) – V(IOUTx)
< 100 mV |
FAULT | Pulled low | Externally
pulled high |
All strings stay ON | Yes | |
Floating | Failing string stays ON, other channels turned OFF | ||||||||
Short to battery:
1 or several LED strings |
V(VIN) > 5 V | ON or OFF | V(VIN) – V(IOUTx)
< 100 mV |
FAULT | Pulled low | Externally
pulled high |
All strings stay ON | Yes | |
Floating | Failing string stays ON, other channels turned OFF | ||||||||
Thermal shutdown | V(VIN) > 5 V | ON or OFF | Temperature > 170°C | FAULT | Pulled low | Externally
pulled high |
All strings turned OFF | Temperature < 155°C | Yes |
Leave open | |||||||||
Thermal foldback | V(VIN) > 5 V | ON or OFF | Temperature > 110°C | N/A | None | N/A | All strings with
reduced current |
Temperature < 100°C | Yes |
Reference resistor
open or shorted |
V(VIN) > 5 V | ON or OFF | R(REF) > 57 kΩ
or R(REF) < 350 Ω |
FAULT | Pulled low | N/A | All strings turned OFF | Toggle EN,
power cycle |
No |