Microelectronics

The Delphi QPCD is a custom High Voltage CMOS IC that is able to drive four permanent magnet DC motors. Using a new position feedback technique, it detects and counts the brush commutation pulses generated by the motor. The QPCD is capable of independently driving up to four 350 mA motors in an automotive environment while simultaneously sensing the 25 mV commutation pulses returned from them. This IC provides a simple interface between the motors and a microcontroller. Each motor is driven by a low-impedance H-bridge in either a CW or CCW direction or put in a brake mode at the direction of a tri-state signal from the microcontroller. Commutation signals from the motors are appropriately amplified and filtered before triggering a one-shot circuit that generates a digital pulse (one for each motor) that is returned to the host microcontroller. The output transistors for the channel-one H-bridge have four-ohm (max.) output transistors, while the other three H-bridges have eight-ohm (max.) transistors. Otherwise, all four channels are identical. The pulse width of the four one-shots is set by an external resistor connected to pin 5.

Features

• Drives four pulse-count motors independently
• Bi-directional motor control with dynamic braking
• Output short circuit protection
• Thermal shutdown
• Over-voltage and under-voltage protection
• Four pulse-detector circuits to determine motor position
• Adjustable detector sensitivity
• Adjustable one-shot pulse width
• False stop pulse reduction
• Simple microprocessor interface
• Two test modes
• Low cost
  

Packaging

• 300 mil wide, 28-pin SOIC

Typical Applications

• HVAC air vane acutators
• Process control
• Fluid metering
• Avionics
  

Pulse Count Technique

* Vign is defined as voltage supplied directly to the IGN pins