Electronic Design

Power-Management ICs Enhance OLEDs, White LED Backlighting

An organic LED (OLED) dc-dc converter IC and a white LED charge pump enhance OLEDs and white LED backlighting while providing flexible power control and efficiency.

Developed by Texas Instruments, the TS65130 OLED driver boasts adjustable output voltages from −12 to 15 V and an 800-mA switch current limit. It's up to 89% efficient at the positive output-voltage rail and 81% efficient at the negative output-voltage rail. Also, its power-save mode brings high efficiency at low load currents.

The TS65130 fits charge-coupled-device (CCD) sensor supply applications in cell phones, PDAs, digital cameras, and camcorders. With an input voltage of 2.7 to 5.5 V, it can be powered from single-cell lithium-ion (Li-Ion) and multicell nickel-metal-hydride (NiMH), nickel-cadmium (NiCd), and alkaline batteries.

This device comes in a small, 4- by 4-mm QFN package. It operates at a fixed-frequency pulse-width-modulated (PWM) signal of 1.25 MHz minimum, permitting the use of tiny 4.7-µH inductors. Independent enable pins permit power-up and power-down sequencing for both outputs.

TI's TPS60230 white LED charge-pump IC manages the power supplied to the display backlight in cell-phone, PDA, digital-camera, and camcorder applications without the need for an inductor. Its regulated output current features 0.3% matching over temperature. Efficiency is up to 87%.

The device can drive up to five LEDs at 25 mA each and switches at 1 MHz, enabling the use of capacitors under 1 µF. Brightness levels for each LED are adjustable through PWM dimming functions on two enable input pins. Housed in a 3- by 3-mm QFN package, the IC features an input-voltage range of 2.7 to 6.5 V and internal soft-start limits for inrush current.

In lots of 1000, the TPS65130 costs $2.95 each, and the TPS60230 charge pump costs $1.55 each.

Texas Instruments
(800) 477-8924

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