Safety Circuit for a Household Appliance

• US 20110007440A1
• Filed: 11/27/2008
• Published: 01/13/2011
• Est. Priority Date: 12/27/2007
• Status: Active Grant

• Current Assignee: Korea Electronics Technology Institute (Government of South Korea)
• Original Assignee: Korea Electronics Technology Institute (Government of South Korea)
• Inventors: Yilmaz, Namik
• Granted Patent: US 8,559,148 B2
• Time in Patent Office: Days
• US Class Current: 361/86
• CPC Class Codes: G05B 9/02 electric
• CPC Class Codes: H05B 1/0252 Domestic applications

Abstract

The present invention relates to a household appliance (1) comprising a control circuit (2) that maintains the electronic control and a safety circuit (3) that detects the errors in the control circuit (2) and cuts off the output of the circuit (2) in case an error occurs. The errors are detected by comparing the output of the control circuit (2) with a reference signal having a square wave form.

Claims

1. A household appliance (1) comprising a control circuit (2) that maintains the electronic control and a safety circuit (3) that detects the errors in the control circuit (2) and cuts off the output of the circuit (2) in case an error occurs and characterized by a safety circuit (3) comprising thereby maintains the reliability control of the circuit (2) in two phases by means of

a comparator (4) that compares hardware-wise the output voltage (Vin) of the control circuit (2) with a full wave form benchmark, having low (V_L) and high (V_H) limit values and a block circuit (5) that converts the output signal (V1) of the comparator (4) to supply voltage if within the determined values, and cuts off if outside, and

a switching unit (6) connected to the output (V2) of the block circuit (5), actuated with the same variable signal as the control circuit (2), and cuts off the output (Vin) of the control circuit (2) if an unwanted signal is detected at the output (V2) of the block circuit (5).

2. A household appliance (1) as in claim 1, characterized by a safety circuit (3) that comprises a comparator (4) wherein the output voltage

will be equal to the benchmark when the output voltage (Vin) of the control circuit (2) is within the limits of the benchmark (V_L<

Vin<

V_H)

and equal to zero if above (Vin>

V_H) ,

equal to the supply voltage (Vcc) when below (Vin<

V_L).

3. A household appliance (1) as in any one of the above claims, characterized by a block circuit (5) disposed at the exit of the comparator (4) and wherein supply voltage (Vcc) is seen at its exit if output voltage (V1) of the comparator (4) is equal to the benchmark, and cuts off the output of the control circuit (2) if different from the benchmark.

4. A household appliance (1) as in any one of the above claims, characterized by a switching unit (6) comprising serially connected control transistors (Q2 and Q3) that are turned on only if of the control circuit (2) delivers the desired output voltage (Vin).

5. A household appliance (1) as in any one of the above claims, which is a cooking device wherein the temperature control is implemented by a safety circuit (3).

6. A household appliance (1) as in claim 5, characterized by a safety circuit (3) that controls the output voltage (Vin) of the temperature sensor which measures the temperature of the control circuit (2).