Protection circuit for motor driving device and motor driving device

Abstract

The utility model discloses a protection circuit used for a motor driving device, the protection circuit comprises at least one power switch tube and a boost circuit, the at least one power switch tube is an NMOS tube and is arranged at the high side of a power supply, and the grid electrode of the at least one power switch tube is connected with the output end of the boost circuit; the booster circuit is composed of a part of circuits in a motor driving chip of the motor driving device, the motor driving chip is connected with the input positive end of the power supply, and the part of circuits control the booster circuit to boost the voltage of the input positive end. And the boosted voltage is output to the grid electrode of the at least one power switch tube. The motor driving device can reduce the cost and improve the performance of the motor driving device.

Description

TECHNICAL FIELD

[0001] The utility model relates to motor technology field especially relates to a protection circuit for motor drive device and motor drive device. BACKGROUND

[0002] In the motor use process, if the operator is careless or the positive and negative polarities of the power supply are not clear, the positive and negative polarities of the control circuit are connected reversely with the positive and negative polarities of the power supply, and the control circuit is permanently damaged, and the motor cannot run. Figure 1 and Figure 6 As shown in the drawings, a diode is connected in series to the motor input main loop, the positive pole of the diode is connected to the positive pole of the power supply and serves as the input end of the main loop, and the negative pole is connected to the main circuit of the drive chip. Figure 2 As shown in the drawings, the source and drain of a power PMOS tube are connected in series to the motor input main loop, the drain of the PMOS tube is connected to the positive pole of the power supply and serves as the input end of the main loop, the source is connected to the main circuit of the drive chip, and the gate is connected to the ground through a resistor.

[0003] When the prior art uses a diode or a PMOS tube as a power reverse connection protection circuit element, another PMOS tube is used as a hot plug function circuit element, the diode and the PMOS tube are connected in series, and are connected to the motor input main loop, as shown in the drawings. Figure 3 As shown in the drawings, two PMOS tubes are connected in series and are connected to the motor input main loop. Figure 4

[0004] As shown in the drawings, on the basis of connecting two NMOS tubes in series and connecting to the motor input main loop, an external charge pump circuit is connected to provide a boosted voltage higher than the positive end of the power supply for the gate of the NMOS tube. Figure 5

[0005] When a diode or a PMOS tube is used for power reverse connection protection or hot plug protection, the forward voltage (VF) of the diode is large, the power consumption is large when applied to a large current, the efficiency is poor, and sometimes multiple diodes need to be connected in parallel to meet the actual application current demand.

[0006] Therefore, the above problems need to be solved. INVENTION CONTENTS

[0007] ​​The utility model discloses a first purpose is to provide a kind of for motor drive device's protection circuit which can reduce cost and improve performance.

[0008] The second purpose of the utility model is to provide a kind of motor drive device.

[0009] To realize above purpose, the utility model discloses a kind of for motor drive device's protection circuit, the protection circuit includes:

[0010] At least one power switch tube and a boost circuit,

[0011] The at least one power switch tube is NMOS pipe, is arranged in power supply high side, and the gate of the at least one power switch tube is connected with the output end of the boost circuit;

[0012] The boost circuit is constituted using part circuit inside the motor drive chip of the motor drive device, the motor drive chip is connected the input positive terminal of the power supply, the part circuit controls the voltage of the input positive terminal to the boost circuit and is boosted voltage output to the gate of the at least one power switch tube.

[0013] Optionally, the at least one power switch tube is the first NMOS pipe, the source of the first NMOS pipe is connected with the input positive terminal of the power supply, the drain of the first NMOS pipe is connected with the load output end of the motor drive device, the gate of the first NMOS pipe is connected with the output end of the boost circuit, and with the boost circuit constitutes anti-reverse connection protection circuit.

[0014] Optionally, the at least one power switch tube is the second NMOS pipe, the drain of the second NMOS pipe is connected with the input positive terminal of the power supply, the source of the second NMOS pipe is connected with the load output end of the motor drive device, the gate of the second NMOS pipe is connected with the output end of the boost circuit, and with the boost circuit constitutes hot plug protection circuit.

[0015] Optionally, protection circuit further includes:

[0016] The first diode is connected with the input positive terminal of the power supply, and the negative terminal of the first diode is connected with the drain of the second NMOS pipe.

[0017] Optionally, the at least one power switch tube comprises a first NMOS tube and a second NMOS tube, a source of the first NMOS tube is connected to an input positive terminal of the power supply, a drain of the first NMOS tube is connected to a drain of the second NMOS tube, a source of the second NMOS tube is connected to a load output terminal of the motor driving device, a gate of the first NMOS tube and a gate of the second NMOS tube are both connected to an output terminal of the voltage boosting circuit, the first NMOS tube and the voltage boosting circuit constitute an anti-reverse connection protection circuit, and the second NMOS tube and the voltage boosting circuit constitute a hot plug protection circuit.

[0018] Optionally, the motor driving chip comprises a pre-driving chip, the voltage boosting circuit comprises a charge pump circuit in the pre-driving chip, and an output terminal of the charge pump circuit is connected to the gate of the at least one power switch tube.

[0019] Optionally, the motor driving chip comprises a DCDC chip, the voltage boosting circuit comprises a voltage boosting module in the DCDC chip, and the gate of the at least one power switch tube is connected to a voltage boosting output terminal of the voltage boosting module.

[0020] Optionally, the motor driving chip further comprises a pre-driving chip, a signal output terminal of the DCDC chip is connected to the pre-driving chip through a third inductor, and the pre-driving chip is provided with a direct current power supply voltage.

[0021] Optionally, the motor driving chip comprises a DCDC chip, the voltage boosting circuit comprises a switch control circuit of a voltage boosting module in the DCDC chip, a signal output terminal of the DCDC chip is led out from the switch control circuit, and the voltage boosting circuit further comprises a first inductor, a second diode and a first capacitor connected in sequence, a connection point of the first inductor and the first capacitor is connected to the signal output terminal of the DCDC chip, and a connection point of the first capacitor and the second diode is connected to the gate of the at least one power switch tube.

[0022] Optionally, the motor driving chip comprises a DCDC chip, the voltage boosting circuit comprises a voltage boosting module in the DCDC chip, and the voltage boosting circuit further comprises a second inductor, a third diode and a second capacitor connected in sequence, the second inductor is connected to a signal output terminal of the DCDC chip, one end of the second capacitor is connected to a voltage boosting output terminal of the voltage boosting module, and the other end of the second capacitor and a connection point of the third diode are connected to the gate of the at least one power switch tube.

[0023] Optionally, the protection circuit further comprises a discharge-preventing diode, a positive terminal of the discharge-preventing diode is connected to an output terminal of the voltage boosting circuit, a negative terminal of the discharge-preventing diode is connected to a gate of the at least one power switch tube through a resistor, and the gate of the at least one power switch tube is further connected to ground through a capacitor.

[0024] Based on the same technical concept, the utility model discloses a motor drive device, including the protection circuit as described above, still include power, motor drive chip and motor, the protection circuit one end is connected the input positive terminal of power, the other end of protection circuit is connected motor, motor drive chip drives motor.

[0025] Beneficial effect: compared with prior art, the utility model has the advantages that: the utility model realizes reverse connection protection by voltage boosting circuit, and also realizes hot plug protection by voltage boosting circuit, further improves the efficiency of motor drive device, the utility model utilizes the voltage boosting circuit in the motor drive chip, or utilizes part of the circuit in the motor drive chip to build voltage boosting circuit to boost the voltage of power input positive terminal, thereby driving the NMOS tube at the high side of power, thereby realizing power reverse connection protection and hot plug protection, without additional external charge pump circuit, the peripheral circuit of high side NMOS tube gate drive is simplified, the additional space occupation of circuit elements on PCB is reduced, the effect of improving efficiency while reducing cost is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 For the principle of the protection circuit in the prior art Figure 1 ;

[0027] Figure 2 For the principle of the protection circuit in the prior art Figure 2 ;

[0028] Figure 3 For the principle of the protection circuit in the prior art Figure 3 ;

[0029] Figure 4 For the principle of the protection circuit in the prior art Figure 4 ;

[0030] Figure 5 For the principle of the protection circuit in the prior art Figure 5 ;

[0031] Figure 6 For the principle of the protection circuit in the prior art Figure 6 ;

[0032] Figure 7For the principle of the embodiment of the utility model Figure 1 ;

[0033] Figure 8 For the principle of the embodiment of the utility model Figure 2 ;

[0034] Figure 9 For the principle of the embodiment of the utility model Figure 3 ;

[0035] Figure 10 For the principle of the embodiment of the utility model Figure 4 ;

[0036] Figure 11 For the principle of the embodiment of the utility model Figure 5 ;

[0037] Figure 12 For the principle of the embodiment of the utility model Figure 6 ;

[0038] Figure 13 For the principle of the embodiment of the utility model Figure 7 ;

[0039] Figure 14 For the principle of the embodiment of the utility model Figure 8 ;

[0040] Figure 15 For the principle of the embodiment of the utility model Figure 9 . Specific implementation

[0041] The utility model provides a protection circuit for motor drive arrangement, protection circuit includes: at least one power switch tube and a boost circuit, at least one power switch tube is NMOS pipe, sets up in power supply high side, and the grid of at least one power switch tube is connected with the output of boost circuit, boost circuit utilizes the partial circuit of motor drive chip inside motor drive arrangement and constitutes, motor drive chip connects the input positive terminal of power supply, partial circuit controls boost circuit to carry out the voltage of input positive terminal and pressurizes, and pressurized voltage is output to the grid of at least one power switch tube, the utility model utilizes the boost circuit of motor drive chip inside, or utilizes the partial circuit of motor drive chip inside and constructs boost circuit to carry out the voltage of power supply input positive terminal and pressurizes, and the difference of pressurized voltage that boost circuit outputs and power supply input positive terminal voltage is greater than the conduction threshold value of NMOS pipe, thereby promotes the NMOS pipe in power supply high side, thereby realizes power supply anti-reverse connection protection, and realizes hot plug protection.

[0042] In one embodiment, at least one power switch is a first NMOS transistor. The source of the first NMOS transistor is connected to the positive input terminal of the power supply, the drain of the first NMOS transistor is connected to the load output terminal of the motor drive device, and the gate of the first NMOS transistor is connected to the output terminal of the boost circuit, and together with the boost circuit, they form a reverse connection protection circuit.

[0043] Specifically, in one embodiment, the motor drive chip includes a pre-drive chip, and the boost circuit includes a charge pump circuit within the pre-drive chip, the output of which is connected to the gate of at least one power switch.

[0044] like Figure 7 As shown, the first NMOS transistor N1 is positioned on the high side of the power supply. The source of the first NMOS transistor N1 is connected to the positive input terminal VCC of the power supply, and the drain of the first NMOS transistor N1 is connected to the load output terminal of the motor drive device. The gate of the first NMOS transistor N1 is connected to the output terminal of the boost circuit, forming a reverse connection protection circuit with the boost circuit. In this embodiment, the boost circuit is constructed using the charge pump circuit inside the motor drive chip. The output terminal VB of the charge pump circuit is connected to the gate of the first NMOS transistor N1 through a resistor. The motor drive chip can be an integrated chip, including a voltage regulator, a controller, a gate driver, and a charge pump circuit. Alternatively, the motor drive chip can be a discrete chip, including a pre-driver chip and a control chip. The pre-driver chip includes a gate driver and a charge pump circuit, and the control chip includes a voltage regulator and a controller. The motor drive chip is connected to the positive input terminal of the power supply. The charge pump circuit boosts the voltage at the positive input terminal and outputs the boosted voltage to the gate of the first NMOS transistor N1, making the gate voltage of the first NMOS transistor N1 higher than the VCC voltage at the positive input terminal, thus driving the first NMOS transistor to work normally.

[0045] This embodiment utilizes the charge pump circuit inside the motor driver chip to drive an external NMOS transistor, thereby achieving reverse connection protection of the power supply. No additional external components are required, which can improve efficiency while reducing costs.

[0046] In one embodiment, the motor drive chip includes a DC-DC converter chip, the boost circuit includes a boost module within the DC-DC converter chip, and the gate of at least one power switch is connected to the boost output terminal of the boost module. For example... Figure 11As shown, the boost module is a BOOST boost circuit inside the DCDC chip, the first NMOS tube N1 is arranged at the high side of the power supply, and the gate of the first NMOS tube N1 is connected with the output end of the boost circuit; specifically, the source of the first NMOS tube N1 is connected with the input voltage VIN of the power supply, the drain of the first NMOS tube N1 is connected with the load output end of the motor driving device, the gate of the first NMOS tube N1 is connected with the negative electrode of the anti-discharge diode D2 through a resistor, the positive electrode of the anti-discharge diode D2 is connected with the boost output end BST, and the gate of the first NMOS tube N1 is also grounded through a capacitor. By arranging the capacitor, the first NMOS tube can be started slowly, and the inrush current can be reduced; the DCDC chip is connected with the negative electrode of the first diode D1, the positive electrode of the first diode D1 is connected with the input voltage VIN of the power supply, and the voltage output by the boost output end BST of the DCDC chip is greater than the input voltage VIN.

[0047] The motor driving chip can be an integrated chip, and the integrated driving chip includes a voltage stabilizer, a controller, a gate driver and a DCDC chip. The motor driving chip can also be a separate chip, and the motor driving chip includes a pre-driving chip and a DCDC chip. The pre-driving chip includes a voltage stabilizer, a controller and a gate driver. The signal output end SW of the DCDC chip is connected with the pre-driving chip through the third inductor L3, and the DCDC chip provides a direct current power supply voltage for the pre-driving chip. The motor driving chip is connected with the input positive end of the power supply. The BOOST boost circuit inside the DCDC chip boosts the voltage of the input positive end VIN, and outputs the boosted voltage to the gate of the first NMOS tube N1, so that the gate voltage of the first NMOS tube N1 is higher than the voltage of the input positive end VIN.

[0048] In this embodiment, the BOOST boost circuit of the DCDC chip inside the motor driving chip is used to drive the first NMOS tube to work normally, and the power supply anti-reverse connection protection is realized. No additional setting is needed outside the chip, and the effect of improving the efficiency while reducing the cost can be achieved.

[0049] In one embodiment, the motor driving chip includes a DCDC chip, the boost circuit includes a switch control circuit of a boost module inside the DCDC chip, a signal output end of the DCDC chip is led out from the switch control circuit, and the boost circuit further includes a first inductor, a second diode and a first capacitor connected in sequence. The connection point of the first inductor and the first capacitor is connected with the signal output end of the DCDC chip, and the connection point of the first capacitor and the second diode is connected with the gate of at least one power switch tube. Figure 13As shown, the first NMOS transistor N1 is arranged at the high side of the power supply, and the gate of the first NMOS transistor N1 is connected with the output end of the boost circuit; specifically, the source of the first NMOS transistor N1 is connected with the input voltage VIN of the power supply, the drain of the first NMOS transistor N1 is connected with the load output end of the motor driving device, the gate of the first NMOS transistor N1 is connected with the negative electrode of the anti-discharge diode D2 through a resistor, the positive electrode of the anti-discharge diode D2 is connected with the signal output end SW of the DCDC chip through the first capacitor C1, and the gate of the first NMOS transistor N1 is also connected with the ground through a capacitor; the DCDC chip is connected with the negative electrode of the first diode D1, and the positive electrode of the first diode D1 is connected with the input voltage VIN of the power supply; the connection point of the first inductor L1 and the first capacitor C1 is connected with the signal output end SW of the DCDC chip, the connection point of the first inductor L1 and the positive electrode of the second diode D3 is connected with the pre-driving chip in the motor driving device, and the connection point of the negative electrode of the second diode D3 and the first capacitor C1 is connected with the positive electrode of the anti-discharge diode D2.

[0050] Part of the circuit inside the motor driving chip is the switch control circuit of the boost module in the DCDC chip, the voltage output by the signal output end SW of the DCDC chip is equal to the input voltage VIN, and the voltage output by the signal output end SW is also output to the driving chip as the direct current power supply voltage VCC after passing through the first inductor L1. The first inductor L1, the second diode D3 and the first capacitor C1 constitute a bootstrap circuit, the switch control circuit of the boost module charges the first capacitor C1 of the bootstrap circuit through switching control, thereby bootstrap boosting the voltage output by SW, that is, the voltage provided for the gate of the first NMOS transistor is the sum of the output voltage value of the signal output end SW and the direct current power supply voltage VCC.

[0051] The motor driving chip can be a separate chip, and the motor driving chip includes a pre-driving chip and a DCDC chip. The pre-driving chip can include a voltage stabilizer, a controller and a gate driver.

[0052] In this embodiment, the signal output end SW of the DCDC chip inside the motor driving chip is used to control the charging of the first capacitor C1 of the bootstrap boost circuit, thereby bootstrap boosting the voltage output by SW to form a high voltage value higher than the input positive terminal VIN voltage, to drive the first NMOS transistor N1 to work normally, and to reduce the control switch elements of the peripheral circuit, thereby improving the efficiency and reducing the cost.

[0053] In one embodiment, the motor driving chip includes a DCDC chip, the boost circuit includes a boost module in the DCDC chip, and the boost circuit further includes a second inductor, a third diode and a second capacitor connected in sequence. The second inductor is connected with the signal output end of the DCDC chip, one end of the second capacitor is connected with the boost output end of the boost module, and the other end of the second capacitor and the connection point of the third diode are connected with the gate of at least one power switch tube.Figure 15 As shown, the boost module can be a BOOST boost circuit within the DCDC chip, the first NMOS tube N1 is arranged at the high side of the power supply, the source of the first NMOS tube N1 is connected to the input voltage VIN of the power supply, and the drain of the first NMOS tube N1 is connected to the load output end of the motor driving device; the gate of the first NMOS tube N1 is connected to the negative electrode of the anti-discharge diode D2 through a resistor, the positive electrode of the anti-discharge diode D2 is connected to the boost output end BST of the boost module through the second capacitor C2, and the gate of the first NMOS tube N1 is also grounded through a capacitor; the DCDC chip is connected to the negative electrode of the first diode D1, and the positive electrode of the first diode D1 is connected to the input voltage VIN of the power supply; a capacitor is connected between the boost output end BST and the signal output end SW of the DCDC chip, the second inductor L2 is connected to the signal output end SW of the DCDC chip, and the connection point of the second inductor L2 and the positive electrode of the third diode D4 is connected to the pre-drive chip in the motor driving device to provide a direct current supply voltage VCC for the pre-drive chip. The positive electrode of the third diode D4 and the connection point of the second capacitor C2 are connected to the positive electrode of the anti-discharge diode D2.

[0054] The boost circuit is composed of part of the circuit inside the motor driving chip of the motor driving device, the part of the circuit inside the motor driving chip is the boost module inside the DCDC chip, and a capacitor is connected between the boost output end BST of the boost module inside the DCDC chip and the signal output end SW of the switch control circuit; the boost output end BST of the DCDC chip is connected to the positive electrode of the anti-discharge diode D2 through the second capacitor C2, the negative electrode of the anti-discharge diode D2 is connected to the gate of the first NMOS tube N1 through a resistor, the boost module inside the DCDC chip boosts the input voltage VIN, that is, the high voltage value output by the boost output end BST is higher than the input voltage VIN, the high voltage value output by the signal output end SW of the DCDC chip is equal to the input voltage VIN, and the high voltage value output by the signal output end SW of the DCDC chip is used to provide a direct current supply voltage VCC for the driving chip after passing through the second inductor L2. The second inductor L2, the third diode D4 and the second capacitor C2 constitute a bootstrap boost circuit, the switch control circuit of the boost module charges the first capacitor C2 of the bootstrap boost circuit through switching control, thereby bootstrap boosting the voltage output by the boost output end BST, that is, the voltage provided for the gate of the first NMOS tube is the sum of the high voltage value output by the boost output end BST and the direct current supply voltage VCC.

[0055] The motor driving chip can be a separate chip, and the motor driving chip includes a pre-drive chip and a DCDC chip, and the pre-drive chip includes a voltage stabilizer, a controller and a gate driver.

[0056] The embodiment further boosts the high voltage output by the boost module of the boost circuit of the DCDC chip, forms a high voltage value higher than the input positive terminal VIN voltage, more easily pushes the NMOS tube to work normally, maintains the stability of the circuit, and achieves the effect of improving efficiency while reducing cost.

[0057] In one embodiment, the at least one power switch tube is a second NMOS tube, the drain of the second NMOS tube is connected to the input positive terminal of the power supply, the source of the second NMOS tube is connected to the load output terminal of the motor driving device, the gate of the second NMOS tube is connected to the output terminal of the boost circuit, and forms a hot plug protection circuit with the boost circuit. Further, in one embodiment, the protection circuit further comprises a first diode, the positive terminal of the first diode is connected to the input positive terminal of the power supply, and the negative terminal of the first diode is connected to the drain of the second NMOS tube. Setting a diode at the input positive terminal of the power supply can perform power anti-reverse connection protection.

[0058] Specifically, as shown in Figure 8 the second NMOS tube N2 is provided at the high side of the power supply, the positive terminal of the first diode D1 is connected to the input positive terminal VCC of the power supply, the negative terminal of the first diode D1 is connected to the drain of the second NMOS tube N2, the source of the second NMOS tube N2 is connected to the load output terminal of the motor driving device, the gate of the second NMOS tube N2 is connected to the output terminal of the boost circuit, and the first diode D1 performs anti-reverse connection protection on the input circuit of the power supply. In the embodiment, the boost circuit is formed by the internal charge pump circuit of the motor driving chip, the output terminal VB of the charge pump circuit is connected to the gate of the second NMOS tube N2 through a resistor, and the gate of the second NMOS tube N2 is also connected to the ground through a capacitor. By setting the capacitor, the second NMOS tube can be started slowly, and the inrush current can be reduced.

[0059] The motor driving chip can be an integrated chip, which includes a voltage stabilizer, a controller, a gate driver and a charge pump circuit. The motor driving chip can also be a separate chip, which includes a pre-driving chip and a control chip. The pre-driving chip includes a gate driver and a charge pump circuit, and the control chip includes a voltage stabilizer and a controller. The motor driving chip is connected to the input positive terminal of the power supply. The charge pump circuit controls the boost circuit to boost the voltage of the input positive terminal, and outputs the boosted voltage to the gate of the second NMOS tube N2, so that the voltage of the gate of the second NMOS tube N2 is higher than the voltage of the input positive terminal VCC.

[0060] The embodiment boosts the input positive terminal of the power supply by the internal charge pump circuit of the motor driving chip, thereby pushing the second NMOS tube to work normally, realizing hot plug protection, and achieving the effect of improving efficiency while reducing cost.

[0061] In other embodiments, the second NMOS tube can be normally driven by using the BOOST boost circuit of the DCDC chip inside the motor drive chip; the charging capacitor of the bootstrap boost circuit can also be charged by using the signal output end SW of the DCDC chip inside the motor drive chip, so as to bootstrap the voltage output by SW, form a high voltage value higher than the input positive voltage, and normally drive the second NMOS tube; the first NMOS tube and the second NMOS tube can also be normally driven by further bootstrap boosting the high voltage output by the boost circuit BOOST of the DCDC chip, forming a high voltage value higher than the input positive voltage VIN, and the specific principle can refer to the above embodiments, which will not be repeated here.

[0062] In one embodiment, the at least one power switch tube includes a first NMOS tube and a second NMOS tube, the source of the first NMOS tube is connected to the input positive end of the power supply, the drain of the first NMOS tube is connected to the drain of the second NMOS tube, the source of the second NMOS tube is connected to the load output end of the motor drive device, the gates of the first NMOS tube and the second NMOS tube are connected to the output end of the boost circuit, the first NMOS tube and the boost circuit constitute an anti-reverse connection protection circuit, and the second NMOS tube and the boost circuit constitute a hot plug protection circuit.

[0063] As shown in Figure 9 and Figure 10 , the at least one power switch tube includes a first NMOS tube N1 and a second NMOS tube N2. The source of the first NMOS tube N1 is connected to the input positive end VCC of the power supply, the drain of the first NMOS tube N1 is connected to the drain of the second NMOS tube N2, the source of the second NMOS tube N2 is connected to the load output end of the motor drive device, the gate of the first NMOS tube N1 is connected to the output end VB of the boost circuit through a resistor, the gate of the second NMOS tube N2 is connected to the output end of the boost circuit through a resistor, and the gate of the second NMOS tube N2 is also connected to ground through a capacitor. The first NMOS tube N1 and the boost circuit constitute an anti-reverse connection protection circuit, and the second NMOS tube N2 and the boost circuit constitute a hot plug protection circuit.

[0064] In this embodiment, the boost circuit is formed by using the charge pump circuit inside the motor drive chip, and the output end VB of the charge pump circuit is connected to the gates of the first NMOS tube N1 and the second NMOS tube N2 through resistors.

[0065] The motor driving chip can be an integrated chip, which includes a voltage stabilizer, a controller, a gate driver and a charge pump circuit. The motor driving chip can also be a separated chip, which includes a pre-driving chip and a control chip. The pre-driving chip includes a gate driver and a charge pump circuit, and the control chip includes a voltage stabilizer and a controller. The motor driving chip is connected to the input positive terminal of the power supply. The charge pump circuit inside the motor driving chip boosts the voltage of the input positive terminal and outputs the boosted voltage to the gate of the first NMOS transistor N1 and the second NMOS transistor N2, so that the gate voltage of the first NMOS transistor N1 and the second NMOS transistor N2 is higher than the input positive terminal VCC voltage.

[0066] The embodiment boosts the input positive terminal of the power supply by using the charge pump circuit inside the motor driving chip, so as to drive the first NMOS transistor and the second NMOS transistor to work normally, thereby realizing the power supply anti-reverse connection protection and the circuit hot plug protection, and achieving the effect of improving the efficiency while reducing the cost.

[0067] In a specific embodiment, a boost circuit is formed by using a boost module of a DCDC chip of the motor driving chip. The boost module can be a BOOST boost circuit, which provides gate drive for the first NMOS transistor and the second NMOS transistor. Figure 12 As shown in FIG. 1, the first NMOS transistor N1 is arranged at the high side of the power supply. The source of the first NMOS transistor N1 is connected to the input voltage VIN of the power supply. The drain of the first NMOS transistor N1 is connected to the drain of the second NMOS transistor N2. The source of the second NMOS transistor N2 is connected to the load output terminal of the motor driving device. The gate of the first NMOS transistor N1 and the gate of the second NMOS transistor N2 are connected to the negative electrode of the anti-discharge diode D2 through a resistor. The positive electrode of the anti-discharge diode D2 is connected to the boost output terminal BST of the boost circuit. The gate of the first NMOS transistor N1 and the gate of the second NMOS transistor N2 are also connected to the ground through a capacitor. By arranging the capacitor, the first NMOS transistor and the second NMOS transistor can be started slowly, and the inrush current can be reduced. The DCDC chip is connected to the negative electrode of the first diode D1. The positive electrode of the first diode D1 is connected to the input voltage VIN of the power supply. The first NMOS transistor N1 and the boost circuit constitute an anti-reverse connection protection circuit. The second NMOS transistor N2 and the boost circuit constitute a hot plug protection circuit.

[0068] The boost output terminal BST of the DCDC chip is connected to the positive electrode of the anti-discharge diode D2. The negative electrode of the anti-discharge diode D2 is connected to the gate of the first NMOS transistor N1 and the gate of the second NMOS transistor N2 through a resistor. The voltage output by the boost output terminal BST of the DCDC chip is greater than the input voltage VIN.

[0069] The motor driving chip can be an integrated chip, which includes a voltage stabilizer, a controller, a gate driver and a DCDC chip. The motor driving chip can also be a separated chip, which includes a pre-driving chip and a DCDC chip. The pre-driving chip includes a voltage stabilizer, a controller and a gate driver. A signal output end SW of the DCDC chip is connected with the pre-driving chip through a third inductor L3, so as to provide a direct current power supply voltage for the pre-driving chip. The motor driving chip is connected with an input positive end of a power supply. The DCDC chip controls a voltage boosting circuit to boost a voltage of the input positive end VIN, and outputs the boosted voltage to gates of a first NMOS tube N1 and a second NMOS tube N2, so that the gates of the first NMOS tube N1 and the second NMOS tube N2 are higher than the voltage of the input positive end VIN.

[0070] In the embodiment, a boosting module (for example, a BOOST boosting circuit) inside the DCDC chip of the motor driving chip is used to boost the input positive end of the power supply, so as to drive the first NMOS tube and the second NMOS tube to work normally, thereby realizing the power anti-reverse connection protection and the circuit hot plug protection, and achieving the effect of improving the efficiency while reducing the cost.

[0071] In another specific embodiment, a signal output end SW of the DCDC chip of the motor driving chip and a peripheral bootstrap circuit are used to form a boosting circuit, so as to provide gate driving for the first NMOS tube and the second NMOS tube. Figure 14As shown, the first NMOS transistor N1 and the second NMOS transistor N2 are arranged at the high side of the power supply, and the gates of the first NMOS transistor N1 and the second NMOS transistor N2 are connected with the output end of the boost circuit; specifically, the source of the first NMOS transistor N1 is connected with the input voltage VIN of the power supply, the drain of the first NMOS transistor N1 is connected with the drain of the second NMOS transistor N2, and the source of the second NMOS transistor N2 is connected with the load output end of the motor driving device; the gates of the first NMOS transistor N1 and the second NMOS transistor N2 are connected with the negative electrode of the anti-discharge diode D2 through a resistor, the positive electrode of the anti-discharge diode D2 is connected with the signal output end SW of the boost circuit through the first capacitor C1, and the gates of the first NMOS transistor N1 and the second NMOS transistor N2 are also connected with the ground through a capacitor; the DCDC chip is connected with the negative electrode of the first diode D1, and the positive electrode of the first diode D1 is connected with the input voltage VIN of the power supply; a capacitor is connected between the boost output end BST and the signal output end SW of the DCDC chip, the connection point of the first inductor L1 and the first capacitor C1 is connected with the signal output end SW of the DCDC chip, the connection point of the first inductor L1 and the positive electrode of the second diode D3 is connected with the pre-driving chip in the motor driving device, thereby providing the direct current power supply voltage VCC for the pre-driving chip, and the connection point of the negative electrode of the second diode D3 and the first capacitor C1 is connected with the positive electrode of the anti-discharge diode D2; the first NMOS transistor N1 and the boost circuit constitute an anti-reverse connection protection circuit, and the second NMOS transistor N2 and the boost circuit constitute a hot plug protection circuit.

[0072] Part of the circuit inside the motor driving chip is a switch control circuit of a boost module in the DCDC chip, the voltage output by the signal output end SW of the DCDC chip is equal to the input voltage VIN, and the voltage output by the signal output end SW is also passed through the first inductor L1 to provide the direct current power supply voltage VCC for the driving chip in one way, the first inductor L1, the second diode D3 and the first capacitor C1 constitute a bootstrap boost circuit, and the switch control circuit of the boost module charges the first capacitor C1 of the bootstrap boost circuit through switching control, thereby performing bootstrap boost on the voltage output by SW, that is, the voltage provided for the gate of the first NMOS transistor is the sum of the output voltage value of the signal output end SW and the direct current power supply voltage VCC.

[0073] The motor driving chip can be a separate chip, and the motor driving chip includes a pre-driving chip and a DCDC chip, and the pre-driving chip includes a voltage stabilizer, a controller and a gate driver. The DCDC chip is connected with the negative electrode of the first diode D1, and the positive electrode of the first diode D1 is connected with the input positive end of the power supply; the DCDC chip controls the boost circuit to boost the voltage of the input positive end VIN, and outputs the boosted voltage to the gates of the first NMOS transistor N1 and the second NMOS transistor N2, so that the gate voltages of the first NMOS transistor N1 and the second NMOS transistor N2 are higher than the voltage of the input positive end VIN.

[0074] The embodiment utilizes the signal output end SW of the DCDC chip inside the motor driving chip to control the charging of the first capacitor C1 of the bootstrap voltage boosting circuit, thereby bootstrap voltage boosting the voltage output by SW, forming a high voltage value higher than the voltage of the input positive end VIN, and driving the first NMOS tube and the second NMOS tube to work normally, achieving the effect of improving the efficiency while reducing the cost.

[0075] In other embodiments, the high voltage output by the voltage boosting circuit BOOST of the DCDC chip can be further bootstrap voltage boosted to form a high voltage value higher than the voltage of the input positive end VIN to drive the first NMOS tube and the second NMOS tube to work normally, and the specific principle can refer to the above embodiment, which will not be repeated here.

[0076] The utility model discloses still a kind of motor driving device, including above-mentioned the protection circuit, still including power supply, motor driving chip and motor, the input positive end of power supply is connected to one end of protection circuit, the other end of protection circuit is connected motor, motor driving chip drives motor.

[0077] The above-mentioned is only the preferred embodiment of the utility model, and does not limit the patent range of the utility model, and any equivalent structural transformation made by the utility model specification and the attached drawings under the concept of the utility model, or direct / indirect application in other related technical fields are included in the patent protection range of the utility model.

Claims

1. A protection circuit for an electric motor drive, characterized in that The protection circuit comprises: at least one power switch tube and a voltage boosting circuit, The at least one power switch tube is an NMOS tube, which is arranged at the high side of the power supply, and the gate of the at least one power switch tube is connected with the output end of the voltage boosting circuit; The voltage boosting circuit is formed by part of the circuit inside the motor driving chip of the motor driving device, the motor driving chip is connected with the input positive end of the power supply, the part of the circuit controls the voltage boosting circuit to boost the voltage of the input positive end, and the boosted voltage is output to the gate of the at least one power switch tube.

2. The protection circuit according to claim 1, wherein The at least one power switch tube is a first NMOS tube, the source of the first NMOS tube is connected with the input positive end of the power supply, the drain of the first NMOS tube is connected with the load output end of the motor driving device, the gate of the first NMOS tube is connected with the output end of the voltage boosting circuit, and the first NMOS tube and the voltage boosting circuit form an anti-reverse connection protection circuit.

3. The protection circuit according to claim 1, wherein The at least one power switch tube is a second NMOS tube, the drain of the second NMOS tube is connected with the input positive end of the power supply, the source of the second NMOS tube is connected with the load output end of the motor driving device, the gate of the second NMOS tube is connected with the output end of the voltage boosting circuit, and the second NMOS tube and the voltage boosting circuit form a hot plug protection circuit.

4. The protection circuit of claim 3, wherein, The protection circuit further comprises: a first diode, the positive end of the first diode is connected with the input positive end of the power supply, and the negative end of the first diode is connected with the drain of the second NMOS tube.

5. The protection circuit according to claim 1, wherein The at least one power switch tube comprises a first NMOS tube and a second NMOS tube, the source of the first NMOS tube is connected with the input positive end of the power supply, the drain of the first NMOS tube is connected with the drain of the second NMOS tube, the source of the second NMOS tube is connected with the load output end of the motor driving device, the gates of the first NMOS tube and the second NMOS tube are both connected with the output end of the voltage boosting circuit, the first NMOS tube and the voltage boosting circuit form an anti-reverse connection protection circuit, and the second NMOS tube and the voltage boosting circuit form a hot plug protection circuit.

6. The protection circuit according to claim 1, wherein The motor driving chip comprises a pre-driving chip, the voltage boosting circuit comprises a charge pump circuit inside the pre-driving chip, and the output end of the charge pump circuit is connected with the gate of the at least one power switch tube.

7. The protection circuit according to claim 1, wherein The motor driving chip comprises a DCDC chip, the voltage boosting circuit comprises a voltage boosting module inside the DCDC chip, and the gate of the at least one power switch tube is connected with the voltage boosting output end of the voltage boosting module.

8. The protection circuit according to claim 7, wherein The motor driving chip further comprises a pre-driving chip, and a signal output end of the DCDC chip is connected with the pre-driving chip through a third inductor to provide a direct current power supply voltage for the pre-driving chip.

9. The protection circuit according to claim 1, characterized in that, The motor driving chip comprises a DCDC chip, the boost circuit comprises a switch control circuit of a boost module in the DCDC chip, a signal output end of the DCDC chip is led out from the switch control circuit, and the boost circuit further comprises a first inductor, a second diode and a first capacitor connected in sequence, the connection point of the first inductor and the first capacitor is connected with the signal output end of the DCDC chip, and the connection point of the first capacitor and the second diode is connected with the gate of the at least one power switch tube.

10. The protection circuit according to claim 1, characterized in that, The motor driving chip comprises a DCDC chip, the boost circuit comprises a boost module in the DCDC chip, the boost circuit further comprises a second inductor, a third diode and a second capacitor connected in sequence, the second inductor is connected with the signal output end of the DCDC chip, one end of the second capacitor is connected with a boost output end of the boost module, and the other end of the second capacitor and the connection point of the third diode are connected with the gate of the at least one power switch tube.

11. Protection circuit according to any of claims 7-10, characterized in that, The protection circuit further comprises an anti-discharge diode, the positive end of the anti-discharge diode is connected with the output end of the boost circuit, the negative end of the anti-discharge diode is connected with the gate of the at least one power switch tube through a resistor, and the gate of the at least one power switch tube is further grounded through a capacitor.

12. A motor driving device comprising the protection circuit according to any one of claims 1-10, further comprising a power supply, a motor driving chip and a motor, one end of the protection circuit is connected with the input positive end of the power supply, the other end of the protection circuit is connected with the motor, and the motor driving chip drives the motor.

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