New DC-DC converters target healthcare and wearable markets

A new series of 0.8A step-up DC-DC converters with load disconnection function has been introduced by Torex. The demand for internal-driver, step-up DC-DC converters in a small package for use in portable devices has been increasing in recent years. There is also an increasing demand for products equipped with an input–output disconnection function (load disconnection function) to prevent malfunctioning during standby, and for device functionality that enables power supply to RTC. Furthermore, there is a significant need for space-saving and the demand for small package lineups and the high efficiency that enables long battery life. A market needs step-up DC-DC converters that save space and have advanced functionality, says the company. In response Torex developed the XC9141/XC9142 series of 0.8A step-up DC-DC converters with a load disconnection function. They target home healthcare and wearable devices that require space saving, advanced functionality, and high efficiency. The ultra-small WLP-6-01 package (1.28mm x 1.08mm x h0.4mm) makes a further contribution to space-saving design. Reduction of the on-resistance of the internal transistor enables high-efficiency supply of a stable current up to 0.8A. When the output voltage is 3.3V, the IC can start from an input voltage of 0.9V with a resistance load of 100ohm, enabling use in devices driven by one alkaline or nickel-hydrogen battery. The input voltage range is 0.65V to 6V, and the output voltage range can be set from 1.8V to 5.5V (accuracy ±2.0%) in steps of 0.1V. A switching frequency of 1.2MHz or 3.0MHz can be selected to match the application. PWM control (XC9141) or PWM/PFM auto switching control (XC9142) can be selected for the operation mode. Internal functions include soft start, load disconnection, CL auto discharge, and a bypass switch function. Internal protective circuits include over-current limiting, integral latch, and output short protection. (The integral latch type is currently under development). The SOT-25 package, small USP-6C package (1.8mm x 2mm x h0.6mm), and ultra-small WLP-6-01 package (1.28,, x 1.08,, x h0.4mm) are available to match the application.