Constant current generation circuit for optocoupler isolation amplifier and current precision adjustment method

A constant current generation circuit for an optocoupler isolation amplifier, comprising a start circuit (1), a current generation circuit and a precision adjustment and output circuit (3) which are integrated into a same substrate, wherein the start circuit (1) can generate and output a first start current and a second start current;

• the current generation circuit comprises a negative temperature change rate current generation circuit (21) and a positive temperature change rate current generation circuit (22), wherein the negative temperature change rate current generation circuit (21) is connected with a first start current output end;
• the positive temperature change rate current generation circuit (22) is connected with a second start current output end;
• and
• the precision adjustment and output circuit (3) is used for outputting a constant current meeting application requirements of the optocoupler isolation amplifier by adjusting proportional precision of two currents outputted from the current generation circuit, wherein the start circuit (1) comprises a diode D1, a resistor R1 and a diode D2 which are connected with a power supply in sequence, wherein an anode of the diode D1 is connected with an output end of the power supply, and a cathode is connected with one end of the resistor R1;
• another end of the resistor R1 is connected with a cathode of the diode D2;
• and the first start current output end and the second start current output end are led out from an anode of the diode D2 via resistors R2 and R3, respectively.