The ESC4 quad speed controller circuit board.
The speed and direction are presented to an internal data
bus for distribution to the PWM and servo modules.
Each PWM motor controller in the module pwm.vhd
converts an eight-bit speed command to a 31. 25 kHz PWM
stream whose duty cycle ranges from 0 to 25%. The
direction bit steers the pulses to the proper H-bridge
driver inputs. There’s one dead clock cycle while
switching the drivers over from active to inactive and
The basic design of notBob was sound, as evidenced by
FIGURE 5. The schematic diagram of one PWM motor controller. The current limit circuitry detects overcurrent on
either lower leg and instructs the CPLD to turn off the power momentarily.
56 SERVO 02.2010