A positive and negative current detection circuit for H-bridge

Abstract

The present application provides a positive and negative current detection circuit for an H-bridge, which includes: a voltage boosting unit, a voltage following unit, a voltage selection unit and a current conversion unit. The voltage boosting unit amplifies the first terminal voltage and the second terminal voltage of a switch tube to be detected, isolates them through the voltage following unit, and determines the target detection voltage to be detected through the voltage selection unit. Finally, the target detection voltage is input to the first terminal of the load switch tube through the current conversion unit to generate a detection current. The controlled end of the load switch tube is connected to the controlled end of the switch tube to be detected. The detection current can be converted to calculate the working current of the switch tube to be detected.

Description

Technical Field

[0001] The present application relates to the technical field of integrated circuits, and in particular to a positive and negative current detection circuit for an H-bridge. Background Art

[0002] At present, in stepper motors, the current flowing through the H-bridge is relatively large, and the stepper motor needs to be stably stopped at an angle. Maintaining the angle requires a fixed two-phase current, which requires precise control of the current flowing through the motor inductor, so it is necessary to detect the current value flowing through the inductor. The current detection technology used in traditional stepper motor drive equipment is mostly through the method of connecting a detection resistor in series and then amplifying the voltage on the resistor through an amplifier. However, in analog integrated circuits, if the detection resistor is too large, the area of ​​the PPA in the unit design will be too large, making the production cost too high, which is contrary to the goal of reducing the production cost of integrated circuits. In addition, the main power of the unit is concentrated on the resistor. Especially for large current detection circuits, too large a resistor will lead to a series of problems such as high power consumption and low work efficiency; and when the resistor is too small, the voltage difference across the detection resistor changes too little, which makes it difficult to read the current value, resulting in reduced current detection accuracy. Summary of the invention

[0003] The present application provides a positive and negative current detection circuit for an H-bridge, which is used to improve the detection accuracy of the working current of the H-bridge and has performed bidirectional detection on the working current of the H-bridge.

[0004] In a first aspect, an embodiment of the present application provides a positive and negative current detection circuit for an H-bridge, the positive and negative current detection circuit for an H-bridge comprising:

[0005] A voltage boosting unit, wherein the first input terminal and the second input terminal of the voltage boosting unit are respectively used to be connected to the first terminal and the second terminal of the switch tube to be detected of the H-bridge, so as to respectively receive the first terminal voltage and the second terminal voltage of the switch tube to be detected, and the voltage boosting unit is further used to amplify the first terminal voltage and the second terminal voltage to a first detection voltage and a second detection voltage respectively;

[0006] a voltage following unit, wherein a first input terminal and a second input terminal of the voltage following unit are respectively connected to a first output terminal and a second output terminal of the voltage boosting unit to receive the first detection voltage and the second detection voltage, and output a first isolation voltage and a second isolation voltage;

[0007] a voltage selection unit, wherein a first input terminal and a second input terminal of the voltage selection unit are respectively connected to a first output terminal and a second output terminal of the voltage follower unit to receive the first isolation voltage and the second isolation voltage, and to determine a target isolation voltage from the first isolation voltage and the second isolation voltage, and to output a target detection voltage according to the target isolation voltage;

[0008] A current conversion unit, the current conversion unit includes: a load switch tube, the input end of the current conversion unit is connected to the output end of the voltage selection unit to input the target detection voltage to the first end of the load switch tube, the controlled end of the load switch tube is connected to the controlled end of the switch tube to be detected, the load switch tube is used to generate a detection current according to the target detection voltage, and the current conversion unit is used to output the detection current.

[0009] In some embodiments, the positive and negative current detection circuit for the H-bridge further includes:

[0010] A current amplifying unit, wherein the input end of the current amplifying unit is connected to the output end of the current converting unit to receive the detection current, and is used to generate a detection amplified current according to the detection current, and the detection amplified current can be converted to obtain the working current of the switch tube to be detected.

[0011] In some embodiments, the voltage follower unit includes: a first operational amplifier and a second operational amplifier;

[0012] The non-inverting input terminal of the first operational amplifier is connected to the first output terminal of the voltage boosting unit, and the reverse direction input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier;

[0013] The non-inverting input terminal of the second operational amplifier is connected to the second output terminal of the voltage boosting unit, and the reverse direction input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier.

[0014] In some embodiments, the voltage selection unit includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a third operational amplifier, a fourth operational amplifier, a first switch tube, a second switch tube and a multiplexer;

[0015] The first end of the first resistor is connected to the output end of the first operational amplifier, the second end of the first resistor is connected to the non-inverting input end of the third operational amplifier, the first end of the second resistor is connected to the output end of the second operational amplifier, the second end of the second resistor is connected to the inverting input end of the fourth operational amplifier, the second end of the second resistor is also connected to the first end of the first switch tube, the output end of the fourth operational amplifier is connected to the controlled end of the first switch tube, the second end of the first switch tube is also connected to the first end of the third resistor, the second end of the third resistor is grounded, and the first end of the third resistor is also connected to the first input end of the multiplexer;

[0016] The first end of the fourth resistor is connected to the output end of the second operational amplifier, the second end of the fourth resistor is connected to the non-inverting input end of the fourth operational amplifier, the first end of the fifth resistor is connected to the output end of the first operational amplifier, the second end of the fifth resistor is connected to the inverting input end of the fourth operational amplifier, the second end of the fifth resistor is also connected to the first end of the second switch tube, the output end of the fourth operational amplifier is connected to the controlled end of the second switch tube, the second end of the second switch tube is also connected to the first end of the sixth resistor, the second end of the sixth resistor is grounded, the first end of the sixth resistor is also connected to the second input end of the multiplexer, and the output end of the multiplexer is the output end of the voltage selection unit.

[0017] In some embodiments, the current conversion unit further includes: a fifth operational amplifier, a third switch tube, a fourth switch tube and a fifth switch tube;

[0018] The non-inverting input terminal of the fifth operational amplifier is connected to the output terminal of the multiplexer, the output terminal of the fifth operational amplifier is connected to the controlled terminal of the third switch tube, the first terminal of the third switch tube is respectively connected to the first terminal of the fourth switch tube, the controlled terminal of the fourth switch tube, and the controlled terminal of the fifth switch tube, the second terminal of the third switch tube is respectively connected to the first terminal of the load switch tube which is the inverting input terminal of the fifth operational amplifier, the second terminal of the fourth switch tube and the second terminal of the fifth switch tube are both connected to a preset voltage source, and the fourth switch tube and the fifth switch tube form a current mirror.

[0019] In some embodiments, the current amplification unit includes: a sixth operational amplifier and a sixth switch tube;

[0020] The non-inverting input end of the sixth operational amplifier is connected to the first end of the fourth switch tube, the inverting input end of the sixth operational amplifier is respectively connected to the first end of the fifth switch tube and the first end of the sixth switch tube, the output end of the sixth switch tube is connected to the controlled end of the sixth switch tube, the second end of the sixth switch tube is the output end of the current amplification unit, and the second end of the sixth switch tube is used to output the detection amplified current.

[0021] In some embodiments, the switch tube to be detected and the load switch tube are switch tubes of the same model.

[0022] In some embodiments, when the H-bridge outputs current to the motor device, the first terminal voltage is greater than the second terminal voltage, and when the motor device outputs current to the H-bridge, the second terminal voltage is greater than the first terminal voltage.

[0023] In a second aspect, an embodiment of the present application provides a chip, wherein the chip includes a positive and negative current detection circuit for an H-bridge as described in any one of the embodiments of the present application.

[0024] In a third aspect, an embodiment of the present application provides an electronic device, which includes a positive and negative current detection circuit for an H-bridge as described in any one of the embodiments of the present application.

[0025] The embodiment of the present application provides a positive and negative current detection circuit for an H-bridge, and the positive and negative current detection circuit for an H-bridge includes: a voltage boosting unit, a voltage following unit, a voltage selecting unit, and a current conversion unit. The first input terminal and the second input terminal of the voltage boosting unit are respectively used to connect with the first terminal and the second terminal of the switch tube to be detected of the H-bridge, so as to respectively receive the first terminal voltage and the second terminal voltage of the switch tube to be detected, and the voltage boosting unit is also used to amplify the first terminal voltage and the second terminal voltage to the first detection voltage and the second detection voltage respectively. The first input terminal and the second input terminal of the voltage following unit are respectively connected to the first output terminal and the second output terminal of the voltage boosting unit to receive the first detection voltage and the second detection voltage, and output the first isolation voltage and the second isolation voltage. The first input terminal and the second input terminal of the voltage selecting unit are respectively connected to the first output terminal and the second output terminal of the voltage following unit to receive the first isolation voltage and the second isolation voltage, and are used to determine the target isolation voltage from the first isolation voltage and the second isolation voltage, and output the target detection voltage according to the target isolation voltage. The current conversion unit includes: a load switch tube, the input end of the current conversion unit is connected to the output end of the voltage selection unit to input the target detection voltage to the first end of the load switch tube, the controlled end of the load switch tube is connected to the controlled end of the switch tube to be detected, the load switch tube is used to generate a detection current according to the target detection voltage, and the current conversion unit is used to output the detection current. Through the above-mentioned positive and negative current detection circuit for the H-bridge, the switch tube to be detected in the H-bridge is amplified through the voltage boost unit to provide a common-mode voltage, and the H-bridge and the subsequent detection unit are isolated through the level follower unit to prevent the detection action from interfering with the H-bridge, and the first isolation voltage and the second isolation voltage are output. In different detection modes, the voltage selection unit selects the target detection voltage according to the first isolation voltage and the second isolation voltage, that is, determines whether the current in the current detection H-bridge is forward or reverse, and finally applies the target detection voltage to the load switch tube to generate a detection current in the load switch tube. The current conversion unit is used to reproduce and output the detection current. Through the above-mentioned detection circuit, there is no need to set a detection resistor in the H-bridge, the detection power consumption is extremely low, the working efficiency is high, and the current output by the H-bridge due to the inductive load of the motor device can be detected, thereby realizing bidirectional detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0027] Figure 1 A schematic flow chart of a first positive and negative current detection circuit for an H-bridge provided in an embodiment of the present application;

[0028] Figure 2 A schematic block diagram of a second positive and negative current detection circuit for an H-bridge provided in an embodiment of the present application;

[0029] Figure 3 A schematic diagram of a positive and negative current detection circuit for an H-bridge provided in an embodiment of the present application.

[0030] Figure Number:

[0031] 200, H bridge; QM1, switch tube to be detected; 100, positive and negative current detection circuit for H bridge; 11, voltage boost unit; 12, voltage follower unit; U1, first operational amplifier; U2, second operational amplifier; 13, voltage selection unit; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; U3, third operational amplifier; U4, fourth operational amplifier; Q1, first switch tube; Q2, second switch tube; MUX, multiplexer; 14, current conversion unit; U5, fifth operational amplifier component; Q3, the third switch tube; Q4, the fourth switch tube; Q5, the fifth switch tube; 15, the current amplification unit; QM2, the load switch tube; VD, the first terminal voltage; VS, the second terminal voltage; VD_RISE, the first detection voltage; VS_RISE, the second detection voltage; VD_BUF, the first isolation voltage; VS_BUF, the second isolation voltage; VD_POS, the target isolation voltage; VDS_DT, the target detection voltage; (+), the non-inverting input terminal; (-), the inverting input terminal; Iqm, the detection current; Iout, the detection amplified current. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0034] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0035] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0036] See also Figure 1 , Figure 1 1 is a schematic block diagram of a first positive and negative current detection circuit for an H-bridge provided in an embodiment of the present application. Figure 1 The positive and negative current detection circuit 100 for the H-bridge includes: a voltage boosting unit 11 , a voltage following unit 12 , a voltage selecting unit 13 and a current converting unit 14 .

[0037] like Figure 1 As shown, the first input terminal and the second input terminal of the voltage boosting unit 11 are respectively used to connect to the first terminal and the second terminal of the switch tube QM1 to be detected of the H-bridge 200, so as to respectively receive the first terminal voltage VD and the second terminal voltage VS of the switch tube QM1 to be detected. The voltage boosting unit 11 is also used to amplify the first terminal voltage VD and the second terminal voltage VS to the first detection voltage VD_RISE and the second detection voltage VS_RISE, respectively.

[0038] Exemplarily, the working current of the H-bridge 200 can be known by detecting the working current of the switch tube QM1 to be detected in any branch of the H-bridge 200. The voltage boost unit 11 includes a DC boost unit, and the first terminal voltage VD and the second terminal voltage VS are respectively amplified to the first detection voltage VD_RISE and the second detection voltage VS_RISE by the DC boost unit. The first detection voltage VD_RISE and the second detection voltage VS_RISE are common mode voltages.

[0039] like Figure 1 As shown, the first input terminal and the second input terminal of the voltage follower unit 12 are respectively connected to the first output terminal and the second output terminal of the voltage boosting unit 11 to receive the first detection voltage VD_RISE and the second detection voltage VS_RISE, and output the first isolation voltage VD_BUF and the second isolation voltage VS_BUF.

[0040] Exemplarily, the first detection voltage VD_RISE and the first isolation voltage VD_BUF are of the same magnitude, and the second detection voltage VS_RISE and the second isolation voltage VS_BUF are of the same magnitude. The H-bridge 200 and subsequent units are isolated by the level follower unit to prevent the detection action from interfering with the H-bridge 200.

[0041] like Figure 1 As shown, the first input terminal and the second input terminal of the voltage selection unit 13 are respectively connected to the first output terminal and the second output terminal of the voltage following unit 12 to receive the first isolation voltage VD_BUF and the second isolation voltage VS_BUF, and are used to determine the target isolation voltage VD_POS from the first isolation voltage VD_BUF and the second isolation voltage VS_BUF, and output the target detection voltage VDS_DT according to the target isolation voltage VD_POS.

[0042] In one embodiment, the target isolation voltage VD_POS is VD_POS when detecting the forward current. The target isolation voltage VD_POS is converted to obtain the target detection voltage VDS_DT.

[0043] In another embodiment, it is VS_NEG when detecting reverse current.

[0044] like Figure 1 As shown, the current conversion unit 14 includes: a load switch tube QM2, the input end of the current conversion unit 14 is connected to the output end of the voltage selection unit 13, so as to input the target detection voltage VDS_DT to the first end of the load switch tube QM2, the controlled end of the load switch tube QM2 is connected to the controlled end of the switch tube QM1 to be detected, the load switch tube QM2 is used to generate a detection current Iqm according to the target detection voltage VDS_DT, and the current conversion unit 14 is used to output the detection current Iqm.

[0045] Exemplarily, the controlled voltages of the load switch tube QM2 and the switch tube to be detected QM1 are the same, and the current conversion unit 14 applies the target detection voltage VDS_DT to the load switch tube QM2, so that the load switch tube QM2 generates a detection current Iqm, and there is also a unit in the current conversion unit 14 for reproducing the detection current Iqm, for example, a current mirror unit, so that the current conversion unit 14 can output the detection current Iqm.

[0046] It should be noted that the detection current Iqm is not equal to the working current of the switch tube QM1 to be detected. The detection current Iqm and the working current of the switch tube QM1 to be detected are in a preset ratio, and the preset ratio can be calculated through the specific structure of the circuit and the characteristics of the components involved.

[0047] The embodiment of the present application provides a positive and negative current detection circuit for an H-bridge, and the positive and negative current detection circuit for an H-bridge includes: a voltage boosting unit, a voltage following unit, a voltage selecting unit, and a current conversion unit. The first input terminal and the second input terminal of the voltage boosting unit are respectively used to connect with the first terminal and the second terminal of the switch tube to be detected of the H-bridge, so as to respectively receive the first terminal voltage and the second terminal voltage of the switch tube to be detected, and the voltage boosting unit is also used to amplify the first terminal voltage and the second terminal voltage to the first detection voltage and the second detection voltage respectively. The first input terminal and the second input terminal of the voltage following unit are respectively connected to the first output terminal and the second output terminal of the voltage boosting unit to receive the first detection voltage and the second detection voltage, and output the first isolation voltage and the second isolation voltage. The first input terminal and the second input terminal of the voltage selecting unit are respectively connected to the first output terminal and the second output terminal of the voltage following unit to receive the first isolation voltage and the second isolation voltage, and are used to determine the target isolation voltage from the first isolation voltage and the second isolation voltage, and output the target detection voltage according to the target isolation voltage. The current conversion unit includes: a load switch tube, the input end of the current conversion unit is connected to the output end of the voltage selection unit to input the target detection voltage to the first end of the load switch tube, the controlled end of the load switch tube is connected to the controlled end of the switch tube to be detected, the load switch tube is used to generate a detection current according to the target detection voltage, and the current conversion unit is used to output the detection current. Through the above-mentioned positive and negative current detection circuit for the H-bridge, the switch tube to be detected in the H-bridge is amplified through the voltage boost unit to provide a common-mode voltage, and the H-bridge and the subsequent detection unit are isolated through the level follower unit to prevent the detection action from interfering with the H-bridge, and the first isolation voltage and the second isolation voltage are output. In different detection modes, the voltage selection unit selects the target detection voltage according to the first isolation voltage and the second isolation voltage, that is, determines whether the current in the current detection H-bridge is forward or reverse, and finally applies the target detection voltage to the load switch tube to generate a detection current in the load switch tube. The current conversion unit is used to reproduce and output the detection current. Through the above-mentioned detection circuit, there is no need to set a detection resistor in the H-bridge, the detection power consumption is extremely low, the working efficiency is high, and the current output by the H-bridge due to the inductive load of the motor device can be detected, thereby realizing bidirectional detection.

[0048] In order to more clearly introduce the technical solution of the present application, the technical solution of the present application will be introduced through specific embodiments below. It should be noted that the specific embodiments are used to expand the technical solution of the present application, but are not intended to limit the present application.

[0049] In some embodiments, see Figure 2 , Figure 2It is a schematic block diagram of the second positive and negative current detection circuit for H-bridge provided in the embodiment of the present application. The positive and negative current detection circuit 100 for H-bridge also includes: a current amplification unit 15. The input end of the current amplification unit 15 is connected to the output end of the current conversion unit 14 to receive the detection current Iqm, and is used to generate the detection amplified current Iout according to the detection current Iqm. The detection amplified current Iout can be converted to obtain the working current of the switch tube QM1 to be detected.

[0050] The detection circuit is amplified by the current amplifier unit 15 to generate a detection amplified current Iout, which provides detection accuracy and sensitivity for the positive and negative current detection circuits of the H-bridge, so that the positive and negative current detection circuits of the H-bridge can detect when the current change of the switch tube QM1 to be detected is small.

[0051] See also Figure 3 , Figure 3 It is a schematic diagram of a positive and negative current detection circuit for an H-bridge provided in an embodiment of the present application.

[0052] like Figure 3 As shown, the voltage boost unit 11 inputs the first terminal voltage VD and the second terminal voltage VS respectively, wherein VDS=VD-VS=Iin*Rdson, wherein Iin is the working current of the switch tube QM1 to be detected, and Rdson is the working resistance of the switch tube QM1 to be detected. After the voltage boost unit 11 boosts the first terminal voltage VD and the second terminal voltage VS respectively, it outputs the first detection voltage VD_RISE and the second detection voltage VS_RISE, wherein the first detection voltage VD_RISE=VD+VCOM, and the second detection voltage VS_RISE=VS+VCOM.

[0053] like Figure 3 As shown, in some embodiments, the voltage follower unit 12 includes: a first operational amplifier U1 and a second operational amplifier U2. The non-inverting input terminal of the first operational amplifier U1 is connected to the first output terminal of the voltage boosting unit 11, and the reverse direction input terminal of the first operational amplifier U1 is connected to the output terminal of the first operational amplifier U1. The non-inverting input terminal of the second operational amplifier U2 is connected to the second output terminal of the voltage boosting unit 11, and the reverse direction input terminal of the second operational amplifier U2 is connected to the output terminal of the second operational amplifier U2.

[0054] Exemplarily, through the connection method shown in the figure, the first detection voltage VD_RISE is the same as the first isolation voltage VD_BUF, and the second detection voltage VS_RISE is the same as the second isolation voltage VS_BUF. That is, VD_RISE=VD_BUF=VD+VCOM, VS_RISE=VS_BUF=VS+VCOM.

[0055] like Figure 3As shown, in some embodiments, the voltage selection unit 13 includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a third operational amplifier U3, a fourth operational amplifier U4, a first switch tube Q1, a second switch tube Q2 and a multiplexer MUX.

[0056] A first end of the first resistor R1 is connected to the output end of the first operational amplifier U1, a second end of the first resistor R1 is connected to the non-inverting input end (+) of the third operational amplifier U3, a first end of the second resistor R2 is connected to the output end of the second operational amplifier U2, a second end of the second resistor R2 is connected to the inverting input end (-) of the fourth operational amplifier U4, a second end of the second resistor R2 is also connected to the first end of the first switch tube Q1, an output end of the fourth operational amplifier U4 is connected to the controlled end of the first switch tube Q1, a second end of the first switch tube Q1 is also connected to the first end of the third resistor R3, a second end of the third resistor R3 is grounded, and a first end of the third resistor R3 is also connected to the first input end of the multiplexer MUX.

[0057] A first end of the fourth resistor R4 is connected to the output end of the second operational amplifier U2, a second end of the fourth resistor R4 is connected to the non-inverting input end (+) of the fourth operational amplifier U4, a first end of the fifth resistor R5 is connected to the output end of the first operational amplifier U1, a second end of the fifth resistor R5 is connected to the inverting input end (-) of the fourth operational amplifier U4, a second end of the fifth resistor R5 is also connected to the first end of the second switch tube Q2, an output end of the fourth operational amplifier U4 is connected to the controlled end of the second switch tube Q2, a second end of the second switch tube Q2 is also connected to the first end of the sixth resistor R6, a second end of the sixth resistor R6 is grounded, a first end of the sixth resistor R6 is also connected to the second input end of the multiplexer MUX, and an output end of the multiplexer MUX is an output end of the voltage selection unit 13.

[0058] Exemplarily, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 are all resistors of the same specification, and the resistance value is r1. The third resistor R3 and the sixth resistor R6 are all resistors of the same specification, and the resistance value is r2. The first isolation voltage VD_BUF and the second isolation voltage VS_BUF are selected by the third operational amplifier U3, the fourth operational amplifier U4, the first switch tube Q1, and the second switch tube Q2.

[0059] When detecting the forward current source, the fourth operational amplifier U4 outputs a low level, the second switch tube Q2 is turned on, and the current in the second switch tube Q2 is I_POS. The specific calculation formula is:

[0060] I_POS=(VD_BUF-VS_BUF) / r1=VDS_BUF / r1=Iin*Rdson / r1;

[0061] When detecting the reverse current source, the third operational amplifier U3 outputs a low level, the first switch tube Q1 is turned on, and the current in the first switch tube Q1 is I_NEG. The specific calculation formula is:

[0062] I_NEG=(VS_BUF-VD_BUF) / r1=VSD_BUF / r1=Iin*Rdson / r1;

[0063] According to I_POS, I_NEG and R2, the target detection voltage VDS_DT can be calculated.

[0064] It should be noted that VD_POS=(r2 / r1)*(VD_BUF-VS_BUF), VS_NEG==(r2 / r1)*(VD_BUF-VS_BUF). The voltage selection unit 13 amplifies the input voltage, that is, amplifies the voltage difference between the first isolation voltage VD_BUF and the second isolation voltage VS_BUF, and the amplification factor is (r2 / r1).

[0065] In one example, when detecting the forward current, the target detection voltage VDS_DT is:

[0066] VDS_DT=VD_POS=I_POS*r2=Iin*Rdson*r2 / r1;

[0067] In order to facilitate the introduction of subsequent circuits, the forward current embodiment is continued.

[0068] It should be noted that when detecting the positive current, VDS_DT=VD_POS. When detecting the negative current, VDS_DT=VDS_NEG. Specifically, if VDS_POS>VDS_NEG, then VDS_DT=VDS_POS, otherwise, VDS_DT=VDS_NEG. Taking VD_POS as an example, VD_POS=(VD_BUF-VS_BUF)*(r2 / r1), where (r2 / r1) is a coefficient, which is set by the circuit.

[0069] In some embodiments, Figure 3 As shown, the current conversion unit 14 further includes: a fifth operational amplifier U5, a third switch tube Q3, a fourth switch tube Q4 and a fifth switch tube Q5.

[0070] The non-inverting input terminal (+) of the fifth operational amplifier U5 is connected to the output terminal of the multiplexer MUX, the output terminal of the fifth operational amplifier U5 is connected to the controlled terminal of the third switch tube Q3, the first terminal of the third switch tube Q3 is respectively connected to the first terminal of the fourth switch tube Q4, the controlled terminal of the fourth switch tube Q4, and the controlled terminal of the fifth switch tube Q5, the second terminal of the third switch tube Q3 is respectively connected to the inverting input terminal (-) of the fifth operational amplifier U5 and the first terminal of the load switch tube QM2, the second terminal of the fourth switch tube Q4 and the second terminal of the fifth switch tube Q5 are both connected to a preset voltage source, and the fourth switch tube Q4 and the fifth switch tube Q5 form a current mirror.

[0071] Exemplarily, through the above circuit, the voltage of the inverting input terminal (-) of the fifth operational amplifier U5 is also the target detection voltage VDS_DT, that is, the target detection voltage VDS_DT is applied to the load switch tube QM2, so that the load switch tube QM2 generates a detection current Iqm. The specific calculation formula of the detection current Iqm is:

[0072] Iqm=VDS_DT / RM=Iin*Rdson*r2 / r1 / Rsense=(r2 / r1)*(Rdson / Rsen)*Iin;

[0073] The detection current Iqm is reproduced through a current mirror formed by the fourth switch tube Q4 and the fifth switch tube Q5, that is, the detection current Iqm is output at the first end of the sixth switch tube.

[0074] In some embodiments, Figure 3 As shown, the current amplifying unit 15 includes: a sixth operational amplifier and a sixth switch tube.

[0075] The non-inverting input terminal (+) of the sixth operational amplifier is connected to the first terminal of the fourth switch tube Q4, the inverting input terminal (-) of the sixth operational amplifier is respectively connected to the first terminal of the fifth switch tube Q5 and the first terminal of the sixth switch tube, the output terminal of the sixth switch tube is connected to the controlled terminal of the sixth switch tube, the second terminal of the sixth switch tube is the output terminal of the current amplification unit 15, and the second terminal of the sixth switch tube is used to output the detection amplified current Iout.

[0076] The current amplification unit 15 multiplies the detection current Iqm by N times, wherein the value range of N is: 1-50. By amplifying the detection current Iqm, the detection amplified current Iout is obtained, and the specific calculation formula is:

[0077] Iout=N*Iqm=N*(r2 / r1)*(Rdson / Rsen)*Iin;

[0078] The detection amplified current Iout is a measurable variable, and the specific value of the working current Iin of the switch tube QM1 to be detected is calculated by conversion through the above formula.

[0079] In some embodiments, the switch tube to be detected QM1 and the load switch tube QM2 are switch tubes of the same model.

[0080] In some embodiments, when the H-bridge 200 outputs current to the motor device, the first terminal voltage VD is greater than the second terminal voltage VS, and the positive and negative current detection circuit 100 for the H-bridge performs a process of detecting a positive current. When the motor device outputs current to the H-bridge, the second terminal voltage VS is greater than the first terminal voltage VD, and the positive and negative current detection circuit 100 for the H-bridge performs a process of detecting a negative current.

[0081] The embodiment of the present application further provides a chip, which includes the positive and negative current detection circuit 100 for an H-bridge as described in any one of the embodiments of the present application.

[0082] An embodiment of the present application further provides an electronic device, which includes the positive and negative current detection circuit 100 for an H-bridge as described in any one of the embodiments of the present application.

[0083] An embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the processor implements a positive and negative current detection circuit for an H-bridge as described in any one of the embodiments of the present application.

[0084] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A positive and negative current detection circuit for an H-bridge, characterized in that: The positive and negative current detection circuit for the H-bridge comprises: A voltage boosting unit, wherein the first input terminal and the second input terminal of the voltage boosting unit are respectively used to be connected to the first terminal and the second terminal of the switch tube to be detected of the H-bridge, so as to respectively receive the first terminal voltage and the second terminal voltage of the switch tube to be detected, and the voltage boosting unit is further used to amplify the first terminal voltage and the second terminal voltage to a first detection voltage and a second detection voltage respectively; a voltage following unit, wherein a first input terminal and a second input terminal of the voltage following unit are respectively connected to a first output terminal and a second output terminal of the voltage boosting unit to receive the first detection voltage and the second detection voltage, and output a first isolation voltage and a second isolation voltage; a voltage selection unit, wherein a first input terminal and a second input terminal of the voltage selection unit are respectively connected to a first output terminal and a second output terminal of the voltage follower unit to receive the first isolation voltage and the second isolation voltage, and to determine a target isolation voltage from the first isolation voltage and the second isolation voltage, and to output a target detection voltage according to the target isolation voltage; A current conversion unit, the current conversion unit includes: a load switch tube, the input end of the current conversion unit is connected to the output end of the voltage selection unit to input the target detection voltage to the first end of the load switch tube, the controlled end of the load switch tube is connected to the controlled end of the switch tube to be detected, the load switch tube is used to generate a detection current according to the target detection voltage, and the current conversion unit is used to output the detection current.

2. The positive and negative current detection circuit for an H-bridge as claimed in claim 1, characterized in that: The positive and negative current detection circuit for the H-bridge also includes: A current amplifying unit, wherein the input end of the current amplifying unit is connected to the output end of the current converting unit to receive the detection current, and is used to generate a detection amplified current according to the detection current, and the detection amplified current can be converted to obtain the working current of the switch tube to be detected.

3. The positive and negative current detection circuit for an H-bridge as claimed in claim 2, characterized in that: The voltage follower unit includes: a first operational amplifier and a second operational amplifier; The non-inverting input terminal of the first operational amplifier is connected to the first output terminal of the voltage boosting unit, and the reverse direction input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier; The non-inverting input terminal of the second operational amplifier is connected to the second output terminal of the voltage boosting unit, and the reverse direction input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier.

4. The positive and negative current detection circuit for an H-bridge as claimed in claim 3, characterized in that: The voltage selection unit includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a third operational amplifier, a fourth operational amplifier, a first switch tube, a second switch tube and a multiplexer; The first end of the first resistor is connected to the output end of the first operational amplifier, the second end of the first resistor is connected to the non-inverting input end of the third operational amplifier, the first end of the second resistor is connected to the output end of the second operational amplifier, the second end of the second resistor is connected to the inverting input end of the fourth operational amplifier, the second end of the second resistor is also connected to the first end of the first switch tube, the output end of the fourth operational amplifier is connected to the controlled end of the first switch tube, the second end of the first switch tube is also connected to the first end of the third resistor, the second end of the third resistor is grounded, and the first end of the third resistor is also connected to the first input end of the multiplexer; The first end of the fourth resistor is connected to the output end of the second operational amplifier, the second end of the fourth resistor is connected to the non-inverting input end of the fourth operational amplifier, the first end of the fifth resistor is connected to the output end of the first operational amplifier, the second end of the fifth resistor is connected to the inverting input end of the fourth operational amplifier, the second end of the fifth resistor is also connected to the first end of the second switch tube, the output end of the fourth operational amplifier is connected to the controlled end of the second switch tube, the second end of the second switch tube is also connected to the first end of the sixth resistor, the second end of the sixth resistor is grounded, the first end of the sixth resistor is also connected to the second input end of the multiplexer, and the output end of the multiplexer is the output end of the voltage selection unit.

5. The positive and negative current detection circuit for an H-bridge as claimed in claim 4, characterized in that: The current conversion unit further includes: a fifth operational amplifier, a third switch tube, a fourth switch tube and a fifth switch tube; The non-inverting input terminal of the fifth operational amplifier is connected to the output terminal of the multiplexer, the output terminal of the fifth operational amplifier is connected to the controlled terminal of the third switch tube, the first terminal of the third switch tube is respectively connected to the first terminal of the fourth switch tube, the controlled terminal of the fourth switch tube, and the controlled terminal of the fifth switch tube, the second terminal of the third switch tube is respectively connected to the first terminal of the load switch tube which is the inverting input terminal of the fifth operational amplifier, the second terminal of the fourth switch tube and the second terminal of the fifth switch tube are both connected to a preset voltage source, and the fourth switch tube and the fifth switch tube form a current mirror.

6. The positive and negative current detection circuit for an H-bridge as claimed in claim 5, characterized in that: The current amplification unit includes: a sixth operational amplifier and a sixth switch tube; The non-inverting input end of the sixth operational amplifier is connected to the first end of the fourth switch tube, the inverting input end of the sixth operational amplifier is respectively connected to the first end of the fifth switch tube and the first end of the sixth switch tube, the output end of the sixth switch tube is connected to the controlled end of the sixth switch tube, the second end of the sixth switch tube is the output end of the current amplification unit, and the second end of the sixth switch tube is used to output the detection amplified current.

7. The positive and negative current detection circuit for an H-bridge as claimed in claim 1, characterized in that: The switch tube to be detected and the load switch tube are switch tubes of the same model.

8. The positive and negative current detection circuit for an H-bridge as claimed in claim 1, characterized in that: When the H-bridge outputs current to the electric device, the voltage at the first terminal is greater than the voltage at the second terminal. When the electric device outputs current to the H-bridge, the voltage at the second terminal is greater than the voltage at the first terminal.

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