Power supplies are used in servers, computers, Power over Ethernet (PoE), telecom, consumer electronics, and industrial applications. The trend today is to go to higher power supplies for general purpose applications, as well in applications such as DVD players, PCs, and TVs. Another trend is towards miniaturization. Some of the power supplies produced today are: high-volume, low-cost DC/DC converters for servers, telecom, AC/DC precision switching supplies – medical, low-cost AC/DC switching supplies, small form factor / bias supplies, and inverters/uninterruptible power supplies. Optocouplers are used in applications in which more than one power level is required and the circuits using those power levels need to be electrically isolated from each other. Optocouplers are used in power supplies for telecom applications that are required to meet safety specifications, such as UL1459. High-efficiency synchronous power supplies utilize high-speed digital optocouplers for gate control or synchronization pulses. Because of the trend to miniaturization of power supplies, higher ambient temperatures can be a problem. Many transistor output optocouplers are now available that can withstand temperatures of up to 110°C.