Drive circuit for direct-current motor

Abstract

The invention discloses a drive circuit for a direct-current motor. The drive circuit comprises an H bridge drive circuit, voltage stabilizing circuits and PWM (Pulse-Width Modulation) drive circuit, wherein the voltage stabilizing circuits comprise a negative voltage stabilizing circuit and a positive voltage stabilizing circuit; the negative voltage stabilizing circuit outputs a voltage with fixed voltage difference relative to the power supply voltage of the system, and is used for generating drive voltage for conducting a P-type MOS (Metal Oxide Semiconductor) tube; the positive voltage stabilizing circuit is used for the drive circuit for conducting a N-type MOS tube; and the PWM drive circuit comprises an upper bridge arm PWM drive circuit and a lower bridge arm PWM drive circuit. The drive circuit for the direct-current motor is not provided with a charge pump, thus, high voltage and oscillation caused by the charge pump is avoided, requirements to voltage resistance performance of a drive circuit chip are reduced, and electromagnetic compatibility of the whole circuit is improved.

Description

technical field [0001] The invention relates to a direct current motor drive circuit, mainly aimed at a COMS type H-bridge motor drive control circuit. Background technique [0002] As an important part of the actuator of the UAV system, the DC motor is used to control the flight attitude and speed of the UAV. The drive circuit to control the DC motor is usually realized by H-bridge drive circuit. [0003] figure 1 Shown is the commonly used H-bridge drive circuit. In the figure, M1, M2, M3 and M4 are four N-type MOS tubes, MOTOR is a DC motor, and G1, G2, G3 and G4 are N-type MOS tubes respectively. gate drive signal. The circuit controls the motor through the PWM signal on G1~G4. When M1 and M4 are turned on at the same time, the motor will rotate in one direction; when M2 and M3 are turned on at the same time, the motor will turn in the opposite direction; M1 and M3 or M2 and M4 are prohibited turn on at the same time. [0004] currently using figure 1 When driving ...

AI Technical Summary

Problems solved by technology

[0007] (1) In order to ensure the normal on-off of the MOS transistors M1 and M2 of the upper arm of the H-bridge, a charge pump circuit must be used, which leads to an increase in the design complexity of the drive circuit and also increases the size of the entire circuit;

[0008] (2) The charge pump circuit will raise the gate signal of the MOS tube to above 28V (input voltage) + Vgs (turn-on voltage) when it is working, which will lead to an increase in the performance requirements of the chip withstand voltage of the drive circuit, which will inevitably increase circuit volume;

[0009] (3) The charge pump circuit needs an oscillating signal to control. If the PWM signal is used as the control signal, the frequency and duty cycle of the PWM signal will be limited; if the internal oscillating signal of the integrated control chip is used, it will give the whole The electromagnetic compatibility of the drive circuit has a certain impact;

[0010] (4) The stable output of the charge pump circuit has a certain delay, which has a certain impact on the rapid start of the motor;

[0011] (5) If a high-speed optocoupler chip is used for isolation, a separate isolated power supply must be used to power the optocoupler chip, which increases the difficulty of design and increases the circuit size

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