| 摘要 |
PURPOSE:To reduce the pattern signal lines needed for switching of a balance network down to just a single piece by using a balance network changeover switch having a swtich selecting function according to the input signal level. CONSTITUTION:When a balance network 2 is set, the level of the input voltage Vin is set at the value between reference voltages Vref1 and Vref2. In this case, the output levels of comparators 21-23 within a switching transistor selection circuit 20 are set at high, low and low levels respectively. While outputs of switching transistor drive circuits 31-34 are set at low, high, low and low levels respectively. As a result, a switching transistor 12 is selected and only this transistor 12 is turned on. |
