INSULATION TRANSFORMER FOR KEY INPUT CIRCUIT

摘要

An insulated transformer for a key input circuit is provided to reduce an operation deviation of the insulated transformer and to improve a signal transmission efficiency by winding first and second coils using a bifilar process to prevent a leaked magnetic flux from increasing. An insulated transformer for a key input circuit includes a core(30), a first coil(41), and a second coil(42). A predetermined air gap is formed on the core. The first and second coils are wound around the core. The insulated transformer is installed on a fly-back converter composed of a key input unit. A microcomputer is installed on a first side of the key input unit. A plurality of resistors and a switch are installed on a second side of the key input unit. The core includes a first core unit, and a second core unit. The air gap is formed on the first core unit. The first and second coils are wound around the first core unit. The second core unit is coupled to both ends of the first core unit. The first and second coils are wound between the first core unit and the second core unit. The second core unit is formed on a circumference of the first core unit.