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Brightness

Control

Disabled

Brightness

Control

Enabled

Brightness

Control Disabled

High

Low

ILED

EFFICIENCY AND FEEDBACK VOLTAGE

UNDERVOLTAGE LOCKOUT

THERMAL SHUTDOWN

CHIPSCALE PACKAGE DIMENSIONS

TPS61060

TPS61061

TPS61062

SLVS538 – NOVEMBER 2004

Between each cycle the ILED pin needs to be pulled high for 1.5 µs.

Figure 15. ILED Timing Diagram

Using the digital interface on the ILED pin allows simple implementation of a two-step brightness control by

The feedback voltage has a direct effect on the converter efficiency. Because the voltage drop across the

feedback resistor does not contribute to the output power (LED brightness), the lower the feedback voltage the

higher the efficiency. Especially when powering only three or less LEDs, the feedback voltage impacts the

efficiency around 2% depending on the sum of the forward voltage of the LEDs. To take advantage of this, the

ILED pin can be connected to VIN, setting the feedback voltage to 250 mV.

An undervoltage lockout prevents mis-operation of the device at input voltages below typical 1.65 V. When the

input voltage is below the undervoltage threshold the device remains off and both internal MOSFETs are turned

off providing isolation between input and output.

An internal thermal shutdown is implemented and turns off the internal MOSFETs when the typical junction

temperature of 160

°C is exceeded. The thermal shutdown has a hysteresis of typically 15°C.

The TPS6106x is available in Chipscale package and has the following mechanical dimensions: E=D=1.446mm

(typ), E=D=1.424mm (min), E=D=1.5mm (max). Please refer to mechanical drawing of the package (YZF).

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