TPS61193

SNVSAF4 – OCTOBER 2015

www.ti.com

Converter SW pin DC current is limited to 2 A (typical). To support short termtransient condition the current limit

is automatically increased to 2.5 A for a short period of 1.5 seconds when a 2-A limit is reached.

NOTE

Application condition where the 2-A limit is exceeded continuously is not allowed. In this

case the current limit would be 2 A for 1.5 seconds followed by 2.5-A limit for 1.5 seconds,

and this 3-second period repeats.

7.3.2 Internal LDO

The internal LDO regulator converts the input voltage at VIN to a 4.3-V output voltage for internal use. Connect a

minimum of 1 µF ceramic capacitor from LDO pin to ground, as close to the LDO pin as possible.

7.3.3 LED Current Sinks

7.3.3.1 Output Configuration

TPS61193 detects LED output configuration during start-up. Any current sink output connected to ground is

disabled and excluded from the adaptive voltage control of the DC-DC and fault detections.

7.3.3.2 Current Setting

current can be calculated using Equation 3:

where

•

•

(3)

7.3.3.3 Brightness Control

TPS61193 controls the brightness of the display with conventional PWM. Output PWM directly follows the input

PWM. Input PWM frequency can be in the range of 100 Hz to 20 kHz. Dimming ratio is calculated as ratio

between the input PWM period and minimum on/off time (0.5 µs).

7.3.4 Protection and Fault Detections

TPS61193 has fault detection for LED open and short, VIN input overvoltage protection (VIN_OVP) , VIN

undervoltage lockout (VIN_UVLO), and thermal shutdown (TSD).

7.3.4.1 Adaptive DC-DC Voltage Control and Functionality of LED Fault Comparators

Adaptive voltage control function adjusts the DC-DC output voltage to the minimum sufficient voltage for proper

efficiency.

Every LED current sink has 3 comparators for the adaptive DC-DC control and LED fault detections. Comparator

outputs are filtered, filtering time is 1 µs.

14

Submit Documentation Feedback

Copyright © 2015, Texas Instruments Incorporated