US 11,934,216 B2
Constant current generation circuit for optocoupler isolation amplifier and current precision adjustment method
Jun Pan, Hefei (CN); Lei Qiu, Hefei (CN); Dianwu Li, Hefei (CN); Fenfen Ji, Hefei (CN); Wei Wang, Hefei (CN); Lei Han, Hefei (CN); and Ke Wang, Hefei (CN)
Assigned to Hefei AICHUANGWEI Electronic Technology Co., Ltd., (CN)
Filed by Hefei AICHUANGWEI Electronic Technology Co., Ltd., Hefei (CN)
Filed on Sep. 30, 2021, as Appl. No. 17/491,087.
Claims priority of application No. 202110099542.9 (CN), filed on Jan. 25, 2021.
Prior Publication US 2022/0236755 A1, Jul. 28, 2022
Int. Cl. G05F 1/56 (2006.01); G05F 1/567 (2006.01); G05F 3/30 (2006.01); H03F 1/30 (2006.01); H03F 3/08 (2006.01); H03F 3/343 (2006.01); H03K 17/78 (2006.01)
CPC G05F 1/567 (2013.01) [G05F 3/30 (2013.01); H03F 1/302 (2013.01); H03F 3/085 (2013.01); H03F 3/3432 (2013.01); H03K 17/78 (2013.01); H03F 2200/447 (2013.01); H03F 2200/91 (2013.01)] 12 Claims
OG exemplary drawing
 
1. 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.