Low-Noise Charge Pump LED Driver Uses 1-Wire Interface
Catalyst Semiconductor, a supplier of high performance mixed-signal and memory solutions, has expanded its family of solid state illumination products with the CAT3614; a tiny 3mm x 3mm, low-noise LED driver with 1-wire EZDim™ interface.
Targeted at portable backlight applications, the CAT3614 drives up to four white light emitting diodes across inputs from 2.5V to 5.5V. Battery life is maximized with the use of an automatic 1x/1.5x charge pump that delivers up to 91% power efficiency. A "zero" current-shutdown limits battery drain in shutdown mode.
Chip enable, shutdown and light emitting diode (LED) dimming are each done using a new 1-wire digital interface. This simple serial interface eliminates the need for pulse-width modulator (PWM) or multi-wire control methods, company officials said. LED current can be controlled in 32 accurate steps of 1 mA each.
The CAT3614's current regulation method reduces flicker and maintains backlight integrity during battery spikes — a common problem in portable systems using media drive, local area network (LAN) or audio power amps, officials said. Further improvements in noise reduction are made by eliminating the LED current setting resistor, which can couple noise during cell phone data transmission, they said.
A tiny hazardous waste (RoHs)-compliant, 3mm x 3mm thin, dual flat no-lead (TDFN) package, low external parts count and high fixed frequency operation all contribute to the reduction of system board area.
The CAT3614 is offered in RoHs "green and gold" packages that are halogen and lead free. Pricing in 1,000-piece quantities is $0.94. Samples, evaluation kits and production quantities are available.
Catalyst Semiconductor produces analog and mixed signal products in addition to a range of nonvolatile memories. Catalyst devices are used in telecommunications, networking systems, computation, automotive, industrial and consumer markets. Typical applications include liquid crystal displays, automotive instrumentation, optical networks, modems, wireless LANs, network cards, dual inline memory modules (DIMMs), cellular telephones, digital satellite box receivers, set-top boxes and Internet routers. Catalyst's quality management system is ISO 9001:2000 certified.
