Juno Step Motor Control IC User Guide
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10
10.Motor Output
In This Chapter
PWM High/Low Motor Output Mode
Sign/Magnitude PWM Output Mode
AmplifierEnable
Brake
The purpose of the motor output module is to generate precisely synchronized PWM (Pulse Width Modulation) signals
for use by external switching amplifier circuitry.
Juno ICs provide two different PWM motor output methods, PWM High/Low, and Sign/Magnitude PWM. The
switching control mode that is used when the current control facility is utilized is PWM High/Low mode. Sign/
Magnitude PWM is typically used with single-IC amplifiers or with bridges that directly input those control interfaces.
To minimize the chance of unexpected motor movement during startup, by default the motor output module is disabled.
To enable motor output the user must enable the corresponding flag of the Operating Mode register.
10.1 PWM High/Low Motor Output
Mode
The Juno step motor control ICs can control high-efficiency MOSFET or IGBT power stages with individual high/low
switch input control. Step motors are driven in a two H-Bridge configuration consisting of 8 switches.
In PWM High/Low mode each signal carries a variable duty cycle PWM signal. A zero desired motor command results
in the high side and low side being active for the same amount of time. Positive motor commands are encoded as a high-
side duty cycle greater than 50%, and negative motor commands are encoded as a duty cycle less than 50%. This is
shown in
.
To activate motor output the motor output flag of the Operating Mode register must be enabled.
