| 摘要 |
PURPOSE:To enable the measuring of internal voltage of an integrated circuit easily and accurately by having a voltage follower made up of a differential amplifier whose negative input is connected to the output thereof, which is connected to a metal pad. CONSTITUTION:A positive input of a differential amplifier 8 is connected to an internal node 2 of an integrated circuit 1 while a negative input thereof to the output thereof, which is connected to a metal pad 4 of a chip composing the integrated circuit 1. A measuring device 9 detects the voltage of the pad 4. When the amplification factor of the differential amplifier 8 is represented by A and input and output voltages Vin and Vout respectively, A(Vin-Vout)=Vout is established and hence, Vout=AVin/(1+A). When the amplification factor A is large enough, Vout-Vin. Therefore, the output voltage Vout to be monitored equals the input voltage Vin. |
