High-side current acquisition and safety protection circuit of a power electronic switch
View Patent ↗The present invention provides a high-side current acquisition and safety protection circuit of a power electronic switch, including a power electronic switch for driving a load, a power supply for providing power energy for the power electronic switch, a control module for sensing the current source signal contained in the power electronic switch and converting the sensed current source signal into a control signal for safety protection of the power electronic switch, and an isolated power source that provides working power for the control module, wherein the negative pole of the isolated power source is connected to the positive pole of the power supply. The invention has simple structure, reliable control, and low cost.
1. A high-side current acquisition and safety protection circuit of a power electronic switch, comprises:
a power electronic switch ( 1 ) for driving a load ( 2 );
a power supply (VP) for providing power energy to the power electronic switch;
a control module ( 3 ) for sensing a current source signal contained in the power electronic switch, and converting the sensed current source signal into a control signal for safety protection of the power electronic switch; and
an isolated power source ( 4 ) for providing working power to the control module, and a negative electrode of the isolated power source is connected to a positive electrode of the power supply (VP),
wherein an input terminal of the power electronic switch ( 1 ) is connected to the power supply (VP), and an output terminal is connected to a load, wherein the power electronic switch ( 1 ) comprises an insulated gate MOSFET,
wherein the control module ( 3 ) comprises a logic control unit ( 31 ), a signal conditioning unit ( 32 ) for transforming the current source signal of the power electronic switch, and a drive conditioning unit ( 33 ) for transforming the control signal for safety protection input by the logic control unit, and
wherein an output port (IO- 1 ) of the logic control unit ( 31 ) is connected to a command input port CIN of the drive conditioning unit ( 33 ), and an output port (OUT) of the drive conditioning unit ( 33 ) is connected to a control terminal (TG) of the power electronic switch ( 1 ), wherein the control terminal (TG) is connected to a gate of the power electronic switch ( 1 ) through a first resistor (R 1 ), wherein an input signal of the command input port (CIN) of the drive conditioning unit ( 33 ) is a logic level signal, wherein an output signal of the output port (OUT) of the drive conditioning unit ( 33 ) is a level signal for driving the power electronic switch, and the level signal is used to control the conduction of the MOSFET.
2. The high-side current acquisition and safety protection circuit of the power electronic switch according to claim 1 , wherein the signal conditioning unit ( 32 ) comprises a second resistor (R 2 ), a third resistor (R 3 ) and a reference power source (VW), wherein an end of the second resistor (R 2 ) is connected to a source of the power electronic switch, the other end of the second resistor (R 2 ) is connected to an end of the third resistor (R 3 ), and the other end of the third resistor (R 3 ) is connected to the reference power source (VW), wherein the reference power source (VW) is an independent power source or a voltage source output by a D/A converter in the logic control unit.
3. The high-side current acquisition and safety protection circuit of the power electronic switch according to claim 1 , wherein the signal conditioning unit ( 32 ) comprises a fourth resistor (R 4 ), a fifth resistor (R 5 ), a sixth resistor (R 6 ), and an operational amplifier (OP), wherein an end of the fourth resistor (R 4 ) is connected to a drain of the power electronic switch ( 1 ), and the other end of the fourth resistor (R 4 ) is connected to a positive electrode of the operational amplifier (OP), wherein an end of the fifth resistor (R 5 ) is connected to a source of the power electronic switch ( 1 ), the other end of the fifth resistor (R 5 ) is connected to a negative electrode of the operational amplifier (OP), wherein an end of the sixth resistor (R 6 ) is connected to the negative electrode of the operational amplifier (OP), and the other end of the sixth resistor (R 6 ) is connected to an output terminal of the operational amplifier (OP).
4. The high-side current acquisition and safety protection circuit of the power electronic switch according to claim 1 , wherein the logic control unit ( 31 ) comprises an A/D converter, a digital logic comparator and a digital threshold level unit, wherein an input of the A/D converter is an output of the signal conditioning unit ( 32 ), wherein the logic control unit ( 31 ) is used to protect the power electronic switch, wherein a first input terminal of the digital logic comparator is connected to an output conversion result of the A/D converter, and a second input terminal of the digital logic comparator is connected to the digital threshold level unit, wherein an output of the digital logic comparator is connected to the command input port (CIN) of the drive conditioning unit ( 33 ), wherein the digital logic comparator comprises a virtual digital logic comparator realized by operation logic or a digital logic comparator configured by software.
5. The high-side current acquisition and safety protection circuit of the power electronic switch according to claim 4 , wherein the logic control unit ( 31 ) further comprises an analog logic comparator, wherein a first input terminal of the analog logic comparator is connected to an output terminal of the signal conditioning unit ( 32 ), and a second input terminal of the analog logic comparator is connected to a configurable analog threshold level, wherein an output of the analog logic comparator is connected to the command input port (CIN) of the drive conditioning unit ( 33 ).
6. The high-side current acquisition and safety protection circuit of the power electronic switch according to claim 5 , wherein outputs of the digital logic comparator and the analog logic comparator are both connected to the output port (IO- 1 ) of the logic control unit ( 31 ), and wherein the logic control unit ( 31 ) performs a logic AND operation on the outputs of the digital logic comparator and the analog logic comparator, and then outputs to the command input port (CIN) of the drive conditioning unit ( 33 ).
7. The high-side current acquisition and safety protection circuit of the power electronic switch according to claim 1 , wherein the isolated power source ( 4 ) includes a DC/DC isolated power source, and the negative electrode of the isolated power source ( 4 ) is connected to a ground terminal of the control module through at least one diode.