OM1682A precision triac control thermostat
The OM1682A integrated circuit is designed for precision temperature control of heating or cooling applications with accurate preset or adjustable temperature control. It functions as an electronic thermostat, and is suitable for a wide range of applications. As well as the zero-crossing mains switching control of a heating element in applications such as water heaters, panel heaters, industrial temperature control, it is capable of controlling inductive loads such as fan motors other more complex loads. The OM1682A is designed to accept a wide variety of resistive and other sensors, using a balanced current comparator input circuit; in which a signal current derived from the sensor is compared with the current derived from a resistor. The OM1682A has additional logic control access, allowing monitoring of the input, and external control of the triac drive. This permit designer to have complete control over systems parameters compared to electromechanical controls. It can also be used without the logic control by leaving pins associated with the logic control (pins SW, LOT and LIN) unconnected.
features
Input-output logic control Variable ON/ OFF cycle time Direct AC mains operation AC powered sensor Control both resistive and inductive loads		Very low supply current Inbuilt regulated DC supply Protection against triac gate spikes Hysteresis from external circuit elements
benefits
Accurate temperature control Allows monitoring of the input External control of triac drive No DC component in supply		Low external component count Low electronic circuitry cost Offers design flexibility Proven solution
applications
Water Heaters Panel Heaters Boiling water units Water coolers Water beds Deep fryers and over controllers		Fan Motors Air conditioners Refrigerators Other complex loads
OM1682A block diagram
applications support
Application note AN001: Power supply circuits for OM1682A triac controller IC applications AN001 focuses on power supply components, mains voltage and load current zero-crossing, triac voltage sensing and load power considerations for OM1682A. Application note AN003: Input Sensing Circuit Design for OM1682A The sensor inputs of the OM1682 allow the use of simple very low power resistive bridge circuits, fed directly from the AC mains supply. Such sensing circuits eliminate the need for a separate DC supply, minimising power supply requirements and susceptibility to uncertain switching due to RFI or spurious mains-born signals. Demo board HM169: Precision electronic thermostat control module The HM169 is an electronic thermostat control module that has been designed using the OM1682A to allow a variety of thermostat control applications.