Hangzhou Ruimeng Tech MS35631N

MS35631 is a quad-channel DMOS full-bridge driver capable of driving two stepper motors or four DC motors. At a 24V supply, each full bridge delivers up to 1A drive current. The device integrates a fixed off-time PWM current regulator and a 2-bit non-linear DAC, supporting full-step, half-step, quarter-step, forward, reverse, and standby modes. The PWM current regulator employs a mixed decay mode, which helps reduce motor audio noise, improve step accuracy, and lower power consumption. An integrated synchronous rectification control circuit further reduces power dissipation during PWM operation. Built-in protection features include thermal shutdown with hysteresis, undervoltage lockout (UVLO), and shoot-through current protection, eliminating the need for a specific power-on sequence. The maximum current limit is determined by the formula ITripMax = VREF / (3 × Rs), where Rs is the sense resistor. In application, the maximum voltage across the sense resistor must not exceed ±500 mV. The internal PWM control circuit has a fixed off-time, set internally to 9 µs. To prevent false triggering, a 1 µs blanking time is provided to disable the output current sense comparator. The device communicates with the controller via standard I1, I0, and PHASE industrial interfaces, enabling full-, half-, and quarter-step modes. Each H-bridge has an independent VREF pin; dynamically controlling this pin enables higher-precision step control. A charge pump circuit generates a supply voltage higher than VBB to drive the high-side DMOS transistors of the H-bridges; the application requires a 0.1 µF ceramic capacitor connected between CP1 and CP2, and another between VCP and VBBx. Comprehensive protection functions are integrated, including over-temperature protection, undervoltage protection, and overcurrent protection. The overcurrent protection detects output shorts to supply, to ground, and between outputs; when a short persists for more than 0.8 µs, the device shuts down the outputs and attempts an automatic restart after 10 ms. The synchronous rectification circuit turns on the corresponding DMOS transistors during current decay to bypass the parasitic body diodes with Rdson resistance, thereby reducing power dissipation; when zero current is detected, synchronous rectification is disabled to prevent load current reversal. The H-bridge operates in mixed decay mode: when the current reaches the current-limit threshold, it first enters fast decay mode (lasting 30.1% of the total decay period), then transitions to slow decay mode. During the fast-to-slow decay transition, the driver turns off for 600 ns (dead time) to prevent bridge shoot-through. Synchronous rectification is inactive during the dead time. The four integrated H-bridge drivers each have independent PWM current control circuits and can therefore also be used to drive four DC motors. In this application, the maximum current is set via the VREF pin, and the motor forward, reverse, and standby operations are controlled by applying PWM signals to the I0x, I1x, and PHASEx pins. For optimal performance and thermal management, it is recommended to solder the MS35631 directly onto the PCB and use the metal thermal pad on its back side to conduct heat to the exposed pad on the PCB.

• Quad full-bridge
• Dual stepper motor drive
• High current output
• Compatible with 3.3V and 5V logic levels
• Synchronous rectification
• Built-in UVLO protection
• Thermal shutdown protection
• Current reversal protection

• Security surveillance
• Stage lighting
• Toys
• Robotics
• Medical devices