| 摘要 |
PURPOSE: A limiting circuit is provided to prevent erroneous operation of washing machines by precisely sensing low-level voltage and to improve reliability of the washing machine. CONSTITUTION: In a circuit, a current detecting resistor (R1), of which an end is grounded, is connected to a non-inverting terminal (+) of a first OP amp (IC1) through a first resistor (R2). By feedback of an output terminal of the first OP amp (IC1), it is connected to inverting terminal (-) of the amplifier (IC1) and to a non-inverting terminal (+) of a second OP amp (IC2) through a second resistor (R3). A capacitor (C1) of which an end is grounded is connected with a third resistor (R5) of which an end is grounded. The connecting point is connected to an inverting terminal (-) of the second OP amp (IC2). An output terminal of the second OP amp (IC2) is connected to the non-inverting terminal (-) of the second OP amp (IC2) through a fourth resistor (R4) and to a non-inverting terminal of a third OP amp (IC3) through a fifth resistor (R6). A sixth resistor (R7), which supply voltage is applied at an end, is a capacitor (C2) and a seventh resistor (R8) that are grounded at their one end, respectively. The connecting point is connected to the inverting terminal (-) of the third OP amp (IC3). And then, an output signal is occurred from the output terminal of the third OP amp (IC3). |
