Circuit detecting electric potential of semiconductor substrate by compensating fluctuation in threshold voltage of transistor

A dynamic memory voltage level detecting circuit compensating for deviation in a threshold voltage level of a drive transistor, said detecting circuit for controlling a predetermined circuit for the dynamic memory, comprising:

• a first transistor, a second transistor, and a third transistor connected in series between a reference voltage line and electrical ground, said first transistor having a gate connected to electrical ground, and said second transistor having a gate connected to a junction of said second transistor and said third transistor, said third transistor having a gate connected to a substrate containing a dynamic memory for detecting a potential of the substrate;
• a fourth drive transistor, and a fifth transistor connected in series between said reference voltage line and electrical ground, said fourth drive transistor having a gate connected to a gate of said second transistor, said fifth transistor having a gate connected to said reference voltage line such that said fifth transistor maintains a conducting state;
• and
• an output signal line connected between said fourth drive transistor and said fifth transistor,
• said second transistor and said fourth drive transistor having a same threshold voltage, such that when said gate of said third transistor detects a high potential on the substrate, said output signal line activates the predetermined circuit, and when said gate of said third transistor detects a low potential on the substrate, said output signal line deactivates the predetermined circuit.