Abstract: A voltage controlled low pass filter comprising first and second circuits connected in series between a filter input and a filter output and a third circuit for adding a DC bias voltage to the filter input with AC signals to be filtered. The first circuit has a gain inversely related to the DC bias voltage and is operative to convert any signal applied to the filter input into a first circuit output signal which is a logarithmic function of the applied signal. The second circuit has a gain directly related to the DC bias voltage such that the overall gain of the first and second circuits is unity. The second circuit also has a bandwidth which is inversely related to the gain of the second circuit, and is operative to convert the first circuit output signal into a signal at the filter output which is an exponential function of the first circuit output signal.

Abstract: An internal power voltage generating circuit of a semiconductor memory device may be constructed with a voltage sensing circuit (100) and a reference voltage controller (300) providing an internal power voltage int. V.sub.CC of a given reference voltage amplitude V.sub.ref and an external power voltage amplitude ext. V.sub.CC. Thus, when a high voltage over an operating voltage of a chip is applied to a pad (10) of the chip, the internal power voltage is raised to the level of the external power voltage. Therefore, when stress is added to the chip during a "burn-in-test", the defective chip is easily detected. Consequently, the reliability of those semiconductor memory devices subjected to post-manufacturing testing can be improved.