7.3.7 Switch Current Limit

The switch current limit prevents the device from high inductor current and drawing excessive current from

battery or input voltage supply. Excessive current might occur with a heavy load or shorted output circuit

condition. The device adopts the peak current control by sensing the current of the high-side switch. Once the

high-side switch current limit is reached, the high-side switch is turned off and low-side switch is turned on to

discharge the inductor current with an adaptive off-time.

7.3.8 Fault Behaviors

The TPS92201 is protected by high-side current limitation in different fault conditions, such as LED open and

short, sense resistor open and short. No matter the fault happens before startup or during operation, the device

can stay safety.

Table 7-1. Fault protection conditions

Fault

Condition

Behavior

LED open

VFB is driven close to 0

VOUT keeps increasing to VIN. and The

high-side switch keeps turn on.

LED anode short to cathode

VFB is driven to VOUT quickly, then

VFB is driven to VOUT quickly, the device

keeps switching by minimum on-time.

LED anode short to GND

VFB is driven close to 0

high-side switch current limit triggered

FB resistor open

VFB is driven to VOUT - Vf

The device keeps switching by the minimum

on-time

FB short to GND

VFB is driven close to 0

VFB is driven close to 0. Current limit is

triggered.

7.3.9 Under Voltage Lockout

To avoid mis-operation of the device at low input voltages, under voltage lockout is implemented that shuts down

the device at voltages lower than VUVLO with VHYS_UVLO hysteresis.

7.3.10 Thermal Shutdown

The device enters thermal shutdown once the junction temperature exceeds the thermal shutdown rising

threshold, TJSD. Once the junction temperature falls below the falling threshold, the device returns to normal

operation automatically.

7.4 Device Functional Modes

7.4.1 Enabling/Disabling the Device

The device is enabled by setting the EN input to a logic High. Accordingly, a logic Low disables the device. If the

device is enabled, the internal power stage starts switching and regulates the output current to the set value. The

EN input must be terminated and should not be floating.

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TPS92201, TPS92201A

SLVSH40B – NOVEMBER 2023 – REVISED AUGUST 2024

Copyright © 2024 Texas Instruments Incorporated

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