TI ultra-small white LED power management solution
Extending its ability to support advanced displays in small battery-powered handheld devices, Texas Instruments Incorporated(TI) announced today a family of synchronous boost converters that can power up to five series white LEDs.
The ultra-small, 1.5 mm x 1.5 mm integrated circuits (ICs) allow portable designers to implement the smallest possible inductor-based solution to efficiently power and control white LED backlights in smart phones, PDAs, digital still cameras and other handheld electronics.
The new TPS6106x family of specialized DC/DC converters support input voltages from 2.7-V to 6-V, and can power up to three-, four- and five-series LEDs. The converters' tiny chip scale package and minimum number of required external components enable a power supply circuit solution smaller than many non-inductor based, charge pump solutions.
The TPS61060, TPS61061 and TPS61062 devices integrate a 400-mA power MOSFET and synchronous rectifier, eliminating the need for an external series Schottky diode. Additionally, the 1-MHz fixed switching frequency allows the converters to work with smaller, low-value external components, such as a 10-uH inductor and a 220-nF output capacitor.
An external current sense resistor sets the regulated LED current. A dedicated input in the TPS6106x devices enables simple, wide-range digital brightness control using a host microcontroller's general purpose input/output pin. The digital dimming technique allows step adjustment of the feedback reference voltage to the regulator. Alternatively, LED brightness can be controlled by applying a pulse-width modulation (PWM) signal to the chip enable pin, or by introducing an analog signal to the feedback input.
For maximum safety and protection, the TPS6106x features integrated over- voltage, and short circuit sensing and thermal shutdown. Each device has a different over-voltage protection threshold (14-V, 18-V and 22.75-V) corresponding to the maximum number of series LEDs. The internal MOSFETs are turned off when the converters are disabled to prevent current leakage into the LEDs and conserve battery power. In shutdown, the parts consume less than 3-uA.
In addition to the new TPS61060, TPS61061 and TPS61062 converters, TI offers a wide variety of high-performance power management and analog products to support white LED backlighting. For example, the TPS61042 inductive solution supports up to eight series white LEDs and is available in an eight- pin QFN package.
The TPS60230 provides a five-channel, 125-mA charge pump solution. The high-current TPS6102x family of 1.5-A switch DC/DC converters is ideally suited for powering the LED flashes in smart phones and digital still cameras.
Evaluation modules, white LED application notes and TI's Power Management Selection Guide are available at http://power.ti.com.
The TPS61060, TPS61061 and TPS61062 are available today in volume from TI and its authorized distributors. Each device is available in an 8-pin, QFN or 8-pin, chip scale package. Suggested resale pricing in quantities of 1,000 is $1.35 for the TPS61060, $1.40 for the TPS61061 and $1.45 for the TPS61062.
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