Automatic adjustment of electrical signal parameters

An implantable active medical device comprising:

• an oscillator circuit having a period of oscillation, said circuit including an adjustable component, the period of oscillation being a function of said adjustable component, a plurality of additional components and a plurality of switches connected to switch selectively said plurality of additional components into said oscillator circuit to adjust the adjustable component, each switch having a switching state;
• a memory register;
• a digital value stored in the memory register corresponding to a switching state of each of said plurality of additional components, the digital value being selectable from one of a plurality of digital values between a minimal digital value and a maximal digital value;
• means for measuring a relationship between the period produced by the oscillator circuit and a period of a predetermined reference value;
• means for determining a difference between the measured relationship and a predetermined control value;
• and
• means for modifying the digital value preserved in the memory register and determining a value which minimizes the determined difference, wherein the modifying means comprises a code generator circuit operable to adjust the digital value by one of incrementation from the minimal value of the digital value until adjusting the digital value provokes a change of sign of said difference.

In an active implantable medical device, an electronic circuit comprising:

• an oscillator circuit having a period of oscillation, said circuit including an adjustable component, the period of oscillation being a function of said adjustable component, a plurality of additional components and a plurality of switches connected to switch selectively said plurality of additional components into said oscillator circuit to adjust the adjustable component;
• a memory register;
• a digital value stored in the memory register corresponding to a switching state of each of said plurality of additional components the digital value being selectable from between a minimal value and a maximal value;
• a counter having a reference period and being operable to count to a number, wherein said number is one of a first number of periods of the oscillator circuit occurring during said reference period and a second number of reference periods occurring during said period of the oscillator circuit;
• a comparator having a first input corresponding to the counted number and a second input corresponding to a control value, and an output representative of a difference between said first and second inputs;
• and
• a code generator circuit operable to adjust the stored digital value by one of incrementation from the minimal value of the digital value and decrementation from the maximal value of the digital value until an adjustment of the digital value provokes a change of sign of said difference.