Power circuit adopts high power double H bridge circuit, use P channel power MOSFET IRF9540 half bridge, half bridge use n-channel MOSFET IRF540 power. So that we can satisfy the drive the bus voltage is 85 v, the phase current of 7 a stepper motor. And using this structure, can simplify the design of drive circuit power supply because don't need multiple isolated drive power, can make the bus power and drive power altogether. For p-channel power MOSFET gate drive used in bridge composed of complementary NPN and PNP transistor drive circuit, make the MOSFET input capacitance charging and discharging circuit of resistance are small and accelerated the on-off of power tube. And through and after another 13 v zener diode, made when the bus voltage is higher clamping MOSFET gate drive voltage, in order to avoid the over grid breakdown voltage source. For bridge under n-channel MOSFET gate drive power driven by simple NPN amplifying circuit, so as to improve the opening process of MOSFET, and reduces the drive power of power; And the transistor's base and emitter diode in parallel, thus provides the input capacitance discharge circuit, accelerated the turn-off process of power tube. When driving circuit to drive the power MOSFET directly caused by driving power MOSFET quickly opened and shut off, this is likely to cause driven power MOSFET drain-source electrode voltage oscillation. In this way, a lead to radio frequency interference; Second is likely to cause power MOSFET of suffer from excessive and broken down. To solve this problem, driven by the power MOSFET gate and drive circuit in series between the output of a 15 non-inductive resistor. On the concrete, the second half of the bridge driving circuit as shown in figure 3 and 4 respectively. L297 output with chopping signal INH1, INH2, and temporal logic signals A, B, C, D after appropriate combination of logic gate, generate PWM1 and PWM2 signal, as the chopping signal input terminal of the driving circuit. the main products: stepper motor, brushless motor, servo motor, stepping motor drive, brake motor, linear motor and other kinds of models of the stepper motor, welcome to inquire. Telephone:
