Microwave ovens have become ubiquitous electronic household cooking appliances due to their cooking method of heating food uniformly. But now modern high-end microwaves provide a variety of preparation functions, such as “simmer”, “deep fry”, “roast”, “steam”, and some models are now capable of baking bread with a “leaven” function. Microwave ovens are starting gaining attention as a healthy electric household appliance, capable of preparing food with low sodium or fat.
In order to implement such functions, microwave ovens increasingly require fine-grained output control, based on data obtained from thermal sensors, infrared sensors, weight sensors, etc. In structural terms, the main output of a microwave oven is produced by a magnetron, with an IGBT performing high-frequency switching and supplying high-voltage output to the magnetron.
Renesas has a broad lineup of microcontroller products suitable for microwave ovens. These include 78K0R/Lx3 and the R8C/LX Series of LCD MCUs, which are built around a high-performance CPU and integrate a PWM (Pulse Width Modulation) function for IGBT control and A/D converters to handle a variety of sensor inputs, and the R8C/33T, which incorporates a touch detection circuit.