U.S. Philips Corporation

Roelf Van Der Wal

Jacob H Botma

Wilhelmus G Ettes

Klaas J Lulofs

Peter Sofrides Viet

Johannes A De Wit

Lawrence S Lai

Wai H Li

Electric toaster with a first heating element arranged at one side of a toasting compartment and a second heating element arranged at an opposed side of the toasting compartment. The first heating element is divided into two sub-elements. Two diodes and a switch provide the possibility to switch over from a normal two-sided toasting mode to an asymmetric single-sided toasting mode. In the normal mode the switch is closed and the sub-elements receive power only during different half-waves of the mains supply voltage, so that the effective radiant power of the sub-divided first element is equal to the radiant power of the second heating element. In the asymmetric mode the switch is opened and the resistance of the first heating element is greater than the resistance of the second element, as a consequence of which relatively more radiant power is emitted by the first heating element than by the second heating element.

Electric toaster with asymmetric heating effect

A flyback converter based on a switcher IC with Pulse Width Modulation control of the switching transistor. The pulse width is controlled by changing the input current at the control input. Under normal operating conditions the voltage at the control input is maintained at a fixed level, which voltage also serves as a supply voltage for the control unit. A charge pump provides extra charge for the smoothing capacitor at the control input when the load would cause the voltage across the smoothing capacitor to collapse below the fixed level, thereby preventing the control unit from entering the auto-restart mode of the switcher IC. In this way the flyback converter can be used as a constant power source for charging rechargeable batteries with a working voltage lower than the nominal operating output voltage of the converter.

Flyback converter with limited output power

A switching power supply with synchronous rectification by means of a diode and a parallel-connected electronic switch. By means of a one-shot circuit the electronic switch is driven into conduction during a fixed portion of the time period during which the diode would be conductive without the electronic switch.

Switching voltage converter with synchronous rectification

A toaster has heating elements (H1, H2) arranged at opposite sides of a product (5) to be toasted. The size of the product to be toasted (5) is detected by a sensor, for example a mechanical sensor (2.1, 2.2, 2.3) or an optical sensor device with a photo-emitter and a photo-receiver. The power delivered by the heating elements (H1, H2) is controlled in dependence on the detected size. Thus, the power consumption of the toaster is adapted to the size of the product to be toasted and overheating of the product is avoided and a constant toasting time is obtained.

Toaster with power output control

A Toaster having heating elements whose heating area depends on the slice size. A toaster has heating elements (H1, H2) divided into sub-elements (H1A, H1B; H2A, H2B) which can be activated individually. The size of the product to be toasted (5) is detected by means of a sensor, for example a mechanical sensor (2) or an optical sensor device with a photo-emitter and a photo-receiver. The sub-elements are activated selectively in dependence on the detected size. Thus, the power consumption of the toaster is adapted to the size of the product to be toasted and overheating of the product in the proximity of the unused heating area of the heating elements is avoided.

Toaster having heating elements whose heating area depends on the slice

A toaster has electrical parts which are energized from a mains voltage. The bread is conveyed to a toasting chamber (4) by means of a lift (6) and a handle (12). In the end position of the handle (12) a main switch (SW5) is turned on, as a result of which the electrical parts can be powered from the mains voltage. The heating elements receive mains voltage via triacs controlled by a microcontroller. After completion of the toasting cycle the microcontroller turns off the heating elements, which precludes burning of the bread, even if the main switch remains in its on-position as a result of a mechanical defect. Subsequently, the microcontroller checks the presence of the mains voltage. In that case a signalling device is activated to warn the user that the mains voltage supply to the toaster has not yet been turned off.

Growing community of inventors

Drachten, Netherlands

Roelf Van Der Wal