Schaltungstechnik

4.4 Operationsverstärker 241
rig : resistance := 0.0; -- common mode input resistance
i0 : current := 0.0; -- internal current
vud0 : voltage := 1.0e5; -- open loop gain
cmrr : real := 3.0e4; -- common mode rejection ratio
r1 : resistance := 500.0e3;-- internal resistance
ck : capacitance := 0.0; -- miller capacitance
ra : resistance := 0.0; -- output resistance
i_max_p : current := 5.0e-3; -- max positive output current
i_max_n : current := -5.0e-3; -- max negativ output current
v_supply_p : voltage := 5.0; -- positive supply voltage
v_supply_n : voltage := -5.0); -- negative supply voltage
PORT (TERMINAL plus, minus, output : electrical);
end OpAmp;
architecture Level2 of OpAmp is
-- inner terminals
terminal n0, n1, n2 : electrical;
-- inner branch quantities and free quantities
quantity Vin across plus to minus;
quantity V_i0 across i2 through plus to n0;
quantity vud across ii, icid, irid through n0 to minus;
quantity vug1 across irig1, iib1 through n0 to electrical_ref;
quantity vug2 across irig2, iib2 through minus to electrical_ref;
quantity vx across ix, ir1 through n1 to electrical_ref;
quantity vck across ick through n2 to n1;
quantity vn2 across in2 through n2 to electrical_ref;
quantity vra across ira through n2 to output;
quantity voutput across output to electrical_ref;
quantity sr : real; -- free quantity: slew rate
quantity ira_h : current; -- help free quantity
quantity vn2_h : voltage; -- help free quantity
begin
sr == i0/ck;
v_i0 == vi0;
ii == ii0/2.0;
icid == cid * vud'dot;
irid == vud/rid;
irig1 == vug1/rig;
irig2 == vug2/rig;
iib1 == iib;
iib2 == iib;
ix == i0 * tanh(vud/0.052);
ir1 == vx/r1;
ick == ck * vck'dot;
vn2_h == vud0*(-1.0*vx)/99.95 + (vud0/cmrr)*vug1;
ira_h == vra/ra;
-- limitation of the output voltage
if vn2_h'above(v_supply_p) use vn2 == v_supply_p;
elsif not vn2_h'above(v_supply_n) use vn2 == v_supply_n;
else vn2 == vn2_h;
end use;
-- limitation of the output current
if ira_h'above(i_max_p) use ira == i_max_p;
elsif not ira_h'above(i_max_n) use ira == i_max_n;
else ira == ira_h;
end use;
end Level2;